Clinical Research: Benefits of FES-Cycling

A low cost clinical exercise system was developed for the spinal cord injured, based on a bicycle ergometer and electrical stimulation. A pilot project was conducted, using the system, to examine the effects of stimulation induced cycling in long term paraplegics. The project comprised 2 phases of exercise, a strengthening phase involving a 12 week programme of electrical stimulation to the quadriceps and hamstrings and a 12 week cycling phase. Physiological, morphological and biochemical parameters were measured for each subject, at the beginning of the programme and following each phase. Results showed that a programme of stimulation induced lower limb exercise increased the exercise tolerance of all patients, as determined by a progressive increase in exercise time, cycling rate and exercise load. The enhanced exercise tolerance was a result of increases in local muscle strength and endurance. Increases in thigh muscle area and joint range of motion were recorded and all incomplete subjects reported an improvement in functional capabilities and general wellbeing.

Twelve patients were involved in a 3 month stimulation induced cycling programme at the Royal Perth Rehabilitation Hospital. A number of the patients were less than 1 year post injury, all except one had an incomplete injury, and most were receiving physiotherapy. All patients who completed the programme increased their time of cycling and, in all but one case, the exercise load, indicative of a local training effect. Significant improvements were found in voluntary isometric strength, stimulated isometric strength and stimulated isometric endurance of the quadriceps, muscle grading of the quadriceps and biceps femoris and the cross-sectional areas of the quadriceps and total thigh muscle. No change was found in voluntary isokinetic strength of the quadriceps. All patients with incomplete injuries reported improvements in the activities of daily living (ADL) after the programme. Bone mineral density (BMD) was examined in two patients, one less than 1 year post injury, and one greater than 4 years post injury. The programme of cycling did not restore BMD in the latter patient. However, while the former patient still displayed a reduced BMD after the programme, it is unknown whether this loss of bone was retarded. This needs further investigation. This study demonstrates the effectiveness of a combined physiotherapy/cycling programme in the rehabilitation of people with spinal injuries. To be successful this type of programme has to be incorporated into the rehabilitation process, as has been done at the Sir George Bedbrook Spinal Unit.

STUDY DESIGN: Longitudinal training.

OBJECTIVES: To determine the effects of functional electrical stimulated (FES) leg cycle ergometer training on muscle histochemical characteristics in individuals with motor-complete spinal cord injury (SCI).

SETTING: University of Alberta, Edmonton, Alberta, Canada.

METHODS: Six individuals with motor-complete SCI (age 31-50 years; 3-25 years post-injury) trained using FES leg cycle ergometry for 30 min, 3 days per week for 8 weeks. Biopsies of the vastus lateralis muscle were obtained pre- and post-training and analyzed for fibre composition, fibre size, and capillarization.

RESULTS: The majority of muscle fibres were classified as type 2 pre- and post-training. Average fibre area increased 23% (P<0.05) and the capillary number increased 39% (P<0.05) with training. As a result of these proportional increases, capillarizatio expressed relative to fibre area was unchanged with training.

CONCLUSIONS: FES leg cycle ergometer training results in proportional increases in fibre area and capillary number in individuals with SCI.

OBJECTIVE: To determine the magnitude of changes in muscle mass and lower extremity body composition that could be induced with a regular regimen of functional electrical stimulation (FES)-induced lower-extremity cycling, as well as the distribution of changes in muscle mass among the thigh muscles in persons with spinal cord injury (SCI).

STUDY DESIGN: Thirteen men with neurologically complete motor sensory SCI underwent a 3-phase, FES-induced, ergometry exercise program: phase 1, quadriceps strengthening: phase 2, progressive sequential stimulation to achieve a rhythmic pedaling motion (surface electrodes placed over the quadriceps, hamstrings, and gluteal muscles); phase 3, FES-induced cycling for 30 minutes. Participants moved from one phase to the next when they met the objectives for the current phase.

MEASURES: Computed tomography of legs to assess muscle cross-sectional area and proportion of muscle and adipose tissue. Scans were done at baseline (before subjects started the program), at first follow-up, typically after 65.4+/-5.6 (SD) weekly sessions, and at second follow-up, typically after 98.1+/-9.1 sessions.

RESULTS: Increases in cross-sectional areas were found in the following muscles: rectus femoris (31%, p<.001). sartorius (22%, p<.025), adductor magnus-hamstrings (26%, p<.001), vastus lateralis (39%, p = .001), vastus medialis-intermedius (31%, p = .025). Cross-sectional area of adductor longus and gracilis muscles did not change. The ratio of muscle to adipose tissue increased significantly in thighs and calves. There was no correlation among the total number of exercise sessions and the magnitude of muscle hypertrophy.

CONCLUSIONS: Muscle cross-sectional area and the muscle to adipose tissue ratio of the lower extremities increased during a regular regimen of 2.3 FES-induced lower extremity cycling sessions weekly. The distribution of changes was related to the proximity of muscles to the stimulating electrodes.

STUDY DESIGN: Single subject pilot.

OBJECTIVES: (i) To see whether strength and endurance for recreational cycling by functional electrical stimulation (FES) are possible following spinal cord injury (SCI). (ii) To develop the equipment for FES-cycling.

SETTING: England.

METHODS: Near-isometric or cycling exercise was performed by the incomplete SCI subject at home.

RESULTS: After training for an average of 21 min per day for 16 months, the stimulated muscles increased in size and the subject was able to cycle for 12 km on the level. Surprisingly, there was a substantial increase in the measured voluntary strength of the knee extensors and the subject reports improved leg function.

CONCLUSION: FES-cycling may promote recovery after incomplete spinal cord injury. If so, it offers the possibility of being a convenient method for widespread use.

PURPOSE: Individuals with spinal cord injuries (SCI) have an increased prevalence of insulin resistance and type 2 diabetes mellitus. In able-bodied individuals, training with large muscle groups increases insulin sensitivity and may prevent type 2 diabetes mellitus. However, individuals with SCI cannot voluntarily recruit major muscle groups, but by functional electrical stimulation (FES) they can now perform ergometer bicycle training.

METHODS: Ten subjects with SCI (35 +/- 2 yr (mean +/- SE), 73 +/- 5 kg, level of lesion C6–Th4, time since injury: 12 +/- 2 yr) performed 1 yr of FES cycling (30 min x d(-1), 3 d x wk(-1) (intensive training)). Seven subjects continued 6 months with reduced training (1 d x wk(-1) (reduced training)). A sequential, hyperinsulinemic (50 mU x min(-1) x m(-2) (step 1) and 480 mU x min(-1) x m(-2) (step 2)), euglycemic clamp, an oral glucose tolerance test (OGTT), and determination of GLUT 4 transporter protein in muscle biopsies were performed before and after training.

RESULTS: Insulin-stimulated glucose uptake rates increased after intensive training (from 4.9 +/- 0.5 mg x min(-1) x kg(-1) to 6.2 +/- 0.6 mg x min(-1) x kg(-1) (P < 0.008) (step 1) and from 9.0 +/- 0.8 mg x min(-1) x kg(-1) to 10.6 +/- 0.8 mg x min(-1) x kg(-1) (P = 0.103) (step 2)). With the reduction in training, insulin sensitivity decreased to a similar level as before training (P > 0.05). GLUT 4 increased by 105% after intense training and decreased again with the training reduction. The subjects had impaired glucose tolerance before and after training, and neither glucose tolerance nor insulin responses to OGTT were significantly altered by training.

CONCLUSIONS: Electrically induced bicycle training, performed three times per week increases insulin sensitivity and GLUT 4 content in skeletal muscle in subjects with SCI. A reduction in training to once per week is not sufficient to maintain these effects. FES training may have a role in the prevention of the insulin resistance syndrome in persons with SCI.

The authors of this prospective, single-case study evaluated the potential for functional recovery from chronic spinal cord injury (SCI). The patient was motor complete with minimal and transient sensory perception in the left hemibody. His condition was classified as C-2 American Spinal Injury Association (ASIA) Grade A and he had experienced no substantial recovery in the first 5 years after traumatic SCI. Clinical experience and evidence from the scientific literature suggest that further recovery would not take place. When the study began in 1999, the patient was tetraplegic and unable to breathe without assisted ventilation; his condition classification persisted as C-2 ASIA Grade A. Magnetic resonance imaging revealed severe injury at the C-2 level that had left a central fluid-filled cyst surrounded by a narrow donutlike rim of white matter. Five years after the injury a program known as “activity-based recovery” was instituted. The hypothesis was that patterned neural activity might stimulate the central nervous system to become more functional, as it does during development. Over a 3-year period (5-8 years after injury), the patient’s condition improved from ASIA Grade A to ASIA Grade C, an improvement of two ASIA grades. Motor scores improved from 0/100 to 20/100, and sensory scores rose from 5-7/112 to 58-77/112. Using electromyography, the authors documented voluntary control over important muscle groups, including the right hemidiaphragm (C3-5), extensor carpi radialis (C-6), and vastus medialis (L2-4). Reversal of osteoporosis and an increase in muscle mass was associated with this recovery. Moreover, spasticity decreased, the incidence of medical complications fell dramatically, and the incidence of infections and use of antibiotic medications was reduced by over 90%. These improvements occurred despite the fact that less than 25 mm2 of tissue (approximately 25%) of the outer cord (presumably white matter) had survived at the injury level. The primary novelty of this report is the demonstration that substantial recovery of function (two ASIA grades) is possible in a patient with severe C-2 ASIA Grade A injury, long after the initial SCI. Less severely injured (lower injury level, clinically incomplete lesions) individuals might achieve even more meaningful recovery. The role of patterned neural activity in regeneration and recovery of function after SCI therefore appears a fruitful area for future investigation.

Two years of functional electrical stimulation cycling (FESC) as a researcher and subject have given me an insight into the direction that future FESC should take as well as providing me with significant health benefits and an enjoyable and functional ability to cycle. If FESC is to benefit spinal cord injured persons (SCIPs), researchers must turn their attention to making the activity convenient and enjoyable. What follows is a personal view and will be less scientifically rigorous than other presentations but hopefully still of value. It calls upon my experience as a general medical practitioner with a special interest in the value of exercise, a human powered vehicle enthusiast, an amateur FES researcher, but most importantly, an SCIP and FES cyclist.

The effect of functional electrical stimulation (FES) training on body composition, assessed by computed tomography, and the effect of spasticity, assessed by both objective and subjective measures, are evaluated. Fifteen motor-complete spinal-cord-injured men participated in the study. Eight of the 15 subjects undertook FES cycling 3 times weekly for 6 months. Whole-body computed tomography scans evaluated changes in body composition. Simultaneous Modified Ashworth Scale and electromyography (EMG) measurements, resistive torque (Kin-Com) and EMG measurements, and self-ratings with Visual Analogue Scale during four consecutive days were used to evaluate changes in spasticity. Lower extremity muscle volume increased by an average of 1300 cm3 (p < 0.001) in the training group compared to the control group, who experienced no change. Otherwise, no changes in body composition were seen. Significant correlations (Spearman) were found between individual EMG activity recordings and movement-provoked Modified Ashworth Scale ratings in 26% of the test situations, irrespective of group and time. The objective and subjective evaluation of movement-provoked passive (viscoelastic) and active (spasticity-related) resistance remained unchanged.

The effect of early intervention using functional electric stimulation cycle ergometry (FES-CE) on skeletal muscle morphology was evaluated in traumatic spinal cord injured (SCI) patients 4 – 6 weeks after injury. Motor complete SCI patients (n = 10) were assigned to either a SCI control group (IC) or FES-CE group (IE) and compared to uninjured controls (UIC) matched for age, activity, and gender. Training via FES-CE was performed 3 days/week for 13 weeks. In the FES-CE trained group, power output increased from 2.4 ± 88 Watts to 24.5 ± 3.2 Watts. Muscle biopsies were taken from the vastus lateralis muscle at pre- and posttraining for subsequent morphological analysis. Without intervention, muscle fiber cross sectional area (CSAf ) decreased 38% and 65% at 6 and 19 weeks post-SCI, respectively. The loss of CSAf had no impact on myonuclear density. Following 13 weeks of FES-CE training, CSAf increased was 63% greater when compared to the IC group. Results of the present investigation suggest that the initiation of FES-CE in first weeks after traumatic SCI attenuates the loss of muscle mass and power output.

OBJECTIVE: To assess the time course of arterial adaptations during 6 weeks of functional electric stimulation (FES) training and 6 weeks of detraining in subjects with spinal cord injury (SCI).

DESIGN: Intervention study (before-after trial). SETTING: University medical center.

PARTICIPANTS: Volunteer sample of 9 subjects with SCI.

INTERVENTIONS: Six weeks of twice weekly FES cycling and 6 weeks of detraining.

MAIN OUTCOME MEASURES: Vascular characteristics were measured by plethysmography (baseline and peak blood flow of the thigh) and echo Doppler (diameter of the femoral artery and flow-mediated dilation [FMD]).

RESULTS: After 2 weeks of FES training, arterial characteristics changed significantly; there was an increase in baseline and peak blood flow, an increase in femoral artery diameter, and a decrease in FMD of the femoral artery. Detraining reversed baseline and peak thigh blood flow, vascular resistance, and femoral diameter toward pretraining values within 1 week. However, detraining did not restore the FMD of the femoral artery, even after 6 weeks.

CONCLUSIONS: Two weeks of hybrid FES training (4 exercise bouts) is sufficient to improve peak leg blood flow and arterial diameter, and to normalize FMD. In addition, detraining results in rapidly reversed vascular characteristics within 1 week.

Functional electrical stimulation (FES)-induced leg exercise offers the potential for individuals with lower-limb paralysis to otherwise gain some benefits conferred by leg exercise. Although its original intent is to reactivate the leg muscles to produce functional upright mobility, as a rehabilitation therapy, FES-evoked exercise increases the whole-body metabolism of individuals with spinal cord injury (SCI) so that they may gain general and localized health and fitness benefits. The physiological and psychosocial responses during FES-evoked cycling, standing, rowing, leg extension, or stepping have been extensively explored for over 20 years. Some of the advantages of such exercise include augmented cardiorespiratory fitness, promotion of leg blood circulation, increased activity of specific metabolic enzymes or hormones, greater muscle volume and fiber size, enhanced functional exercise capacity such as strength and endurance, and altered bone mineral density. Positive psychosocial adaptations have also been reported among SCI individuals who undergo FES exercise. This article presents a position review of the available literature on the effects of FES-evoked exercise since the earliest date until 2007, to warrant a conclusion about the current status and potential of FES-evoked exercise for paralyzed people.

Inactivity and muscular adaptations following spinal cord injury (SCI) result in secondary complications such as cardiovascular disease, obesity, and pressure sores. Functional electrically stimulated (FES) cycling can potentially reduce these complications, but previous studies have provided inconsistent results. We studied the effect of intensive long-term FES cycle training on muscle properties in 11 SCI subjects (mean +/- SEM: 41.8 +/- 2.3 years) who had trained for up to 1 hour/day, 5 days/week, for 1 year. Comparative measurements were made in 10 able-bodied (AB) subjects. Quadriceps maximal electrically stimulated torque increased fivefold (n = 5), but remained lower than in AB individuals. Relative force response at 1 HZ decreased, relaxation rate remained unchanged, and fatigue resistance improved significantly. Power output (PO) improved to a lesser extent than quadriceps torque and not to a greater extent than has been reported previously. We need to understand the factors that limit PO in order to maximize the benefits of FES cycling.

Spinal cord injury (SCI) leads to severe bone loss in the paralysed limbs and to a resulting increased fracture risk thereof. Since long bone fractures can lead to comorbidities and a reduction in quality of life, it is important to improve bone strength in people with chronic SCI. In this prospective longitudinal cohort study, we investigated whether functional electrical stimulation (FES) induced high-volume cycle training can partially reverse the loss of bone substance in the legs after chronic complete SCI. Eleven participants with motor-sensory complete SCI (mean age 41.9+/-7.5 years; 11.0+/-7.1 years post injury) were recruited. After an initial phase of 14+/-7 weeks of FES muscle conditioning, participants performed on average 3.7+/-0.6 FES-cycling sessions per week, of 58+/-5 min each, over 12 months at each individual’s highest power output. Bone and muscle parameters were investigated in the legs by means of peripheral quantitative computed tomography before the muscle conditioning (t1), and after six (t2) and 12 months (t3) of high-volume FES-cycle training. After 12 months of FES-cycling, trabecular and total bone mineral density (BMD) as well as total cross-sectional area in the distal femoral epiphysis increased significantly by 14.4+/-21.1%, 7.0+/-10.8% and 1.2+/-1.5%, respectively. Bone parameters in the femoral shaft showed small but significant decreases, with a reduction of 0.4+/-0.4% in cortical BMD, 1.8+/-3.0% in bone mineral content, and 1.5+/-2.1% in cortical thickness. These decreases mainly occurred between t1 and t2. No significant changes were found in any of the measured bone parameters in the tibia. Muscle CSA at the thigh increased significantly by 35.5+/-18.3%, while fat CSA at the shank decreased by 16.7+/-12.3%. Our results indicate that high-volume FES-cycle training leads to site-specific skeletal changes in the paralysed limbs, with an increase in bone parameters at the actively loaded distal femur but not the passively loaded tibia. Thus, we conclude that high-volume FES-induced cycle training has clinical relevance as it can partially reverse bone loss and thus may reduce fracture risk at this fracture prone site.

Persons with spinal cord injury (SCI) are at a heightened risk of developing type II diabetes and cardiovascular disease. The purpose of this investigation was to conduct an analysis of metabolic, body composition, and neurological factors before and after 10 weeks of functional electrical stimulation (FES) cycling in persons with SCI. Eighteen individuals with SCI received FES cycling 2-3 times per week for 10 weeks. Body composition was analyzed by dual X-ray absorptiometry. The American Spinal Injury Association (ASIA) neurological classification of SCI test battery was used to assess motor and sensory function. An oral glucose tolerance (OGTT) and insulin-response test was performed to assess blood glucose control. Additional metabolic variables including plasma cholesterol (total-C, HDL-C, LDL-C), triglyceride, and inflammatory markers (IL-6, TNF-alpha, and CRP) were also measured. Total FES cycling power and work done increased with training. Lean muscle mass also increased, whereas, bone and adipose mass did not change. The ASIA motor and sensory scores for the lower extremity significantly increased with training. Blood glucose and insulin levels were lower following the OGTT after 10 weeks of training. Triglyceride levels did not change following training. However, levels of IL-6, TNF-alpha, and CRP were all significantly reduced.

OBJECTIVE: To determine the effect of cycling, electrical stimulation, or both, on thigh muscle volume and stimulated muscle strength in children with spinal cord injury (SCI).

DESIGN: Randomized controlled trial.

SETTING: Children’s hospital specializing in pediatric SCI.

PARTICIPANTS: Children (N=30; ages, 5-13y) with chronic SCI.

INTERVENTIONS: Children were randomly assigned to 1 of 3 interventions: functional electrical stimulation cycling (FESC), passive cycling (PC), and noncycling, electrically stimulated exercise (ES). Each group exercised for 1 hour, 3 times per week for 6 months at home.

MAIN OUTCOME MEASURES: Preintervention and postintervention, children underwent magnetic resonance imaging to assess muscle volume, and electrically stimulated isometric muscle strength testing with the use of a computerized dynamometer. Data were analyzed via analyses of covariance (ANCOVA) with baseline measures as covariates. Within-group changes were assessed via paired t tests.

RESULTS: All 30 children completed the training. Muscle volume data were complete for 24 children (8 FESC, 8 PC, 8 ES) and stimulated strength data for 27 children (9 per group). Per ANCOVA, there were differences between groups (P<.05) for quadriceps muscle volume and stimulated strength, with the ES group having greater changes in volume and the FESC group having greater changes in strength. Within-group analyses showed increased quadriceps volume and strength for the FESC group and increased quadriceps volume for the ES group.

CONCLUSIONS: Children receiving either electrically stimulated exercise experienced changes in muscle size, stimulated strength, or both. These changes may decrease their risk of cardiovascular disease, insulin resistance, glucose intolerance, and type 2 diabetes.

Functional electrical stimulation (FES) cycling ergometer has been utilized in recent decades for rehabilitation by sequentially stimulating the large leg-actuating muscles of paralyzed leg muscles to produce cyclical leg motion. A number of studies reported physiological adaptations after regular FES-cycling exercise (FESCE) training in subjects with spinal cord injury, stroke, cerebral palsy and other conditions. This article provides a comprehensive overview of general aspects of FES cycling systems and clinical applications of FESCE. The studies cited in this article provide supportive findings for the potential clinical efficacy of FESCE for reducing the risk of secondary medical complications in subjects with paralysis. The potential therapeutic benefits of FESCE include conditioning the cardiopulmonary, muscular, and skeletal systems, and improving other physiological and psychological performances. Our recent pilot study also indicated that the decrease of leg spasticity in subjects with cerebral palsy is one of the acute effects of FESCE. In conclusion, we recommend that FESCE is of benefit in a variety of aspects to improve the general condition and to prevent deterioration in subjects with central neurological impairments.

OBJECTIVE: To investigate the long-term effects of functional electrical stimulation (FES)-evoked cycle training cadence on leg muscle hypertrophy and electrically evoked strength.

DESIGN: Open intervention study.

SETTING: Laboratory setting.

PARTICIPANTS: Untrained individuals with chronic spinal cord injury (N=8).

INTERVENTIONS: Six weeks (3d/wk) of training on an isokinetic FES cycle ergometer. For each subject, 1 leg was randomly allocated to cycling at 10 revolutions per minute (rpm) (LOW) for 30min/d, and the other cycling at 50rpm (HIGH) for 30min/d.

MAIN OUTCOME MEASURES: Pre- and posttraining measurements of lower limb circumference were performed at the distal and middle position of each thigh. Electrically evoked quadriceps muscle torque during an isometric contraction was also assessed.

RESULTS: Six weeks of FES cycle training significantly increased thigh girth in both LOW and HIGH groups. At midthigh, girth increases induced by LOW (6.6%±1.2%) were significantly greater than those by HIGH (3.6%±0.8%). LOW also produced greater gains in electrically evoked isometric torque than HIGH after training.

CONCLUSIONS: These results suggest that lower pedaling cadences evoke greater muscle hypertrophy and electrically stimulated muscle strength compared with higher cadences.

OBJECTIVE: To examine the effect of long-term lower extremity functional electrical stimulation (FES) cycling on the physical integrity and functional recovery in people with chronic spinal cord injury (SCI).

DESIGN: Retrospective cohort, mean follow-up 29.1 months, and cross-sectional evaluation.

SETTING: Washington University Spinal Cord Injury Neurorehabilitation Center, referral center.

PARTICIPANTS: Twenty-five people with chronic SCI who received FES during cycling were matched by age, gender, injury level, and severity, and duration of injury to 20 people with SCI who received range of motion and stretching.

INTERVENTION: Lower extremity FES during cycling as part of an activity-based restorative treatment regimen.

MAIN OUTCOME MEASURE: Change in neurological function: motor, sensory, and combined motor-sensory scores (CMSS) assessed by the American Spinal Injury Association Impairment scale. Response was defined as ≥ 1 point improvement.

RESULTS: FES was associated with an 80% CMSS responder rate compared to 40% in controls. An average 9.6 CMSS point loss among controls was offset by an average 20-point gain among FES subjects. Quadriceps muscle mass was on average 36% higher and intra/inter-muscular fat 44% lower, in the FES group. Hamstring and quadriceps muscle strength was 30 and 35% greater, respectively, in the FES group. Quality of life and daily function measures were significantly higher in FES group.

CONCLUSION: FES during cycling in chronic SCI may provide substantial physical integrity benefits, including enhanced neurological and functional performance, increased muscle size and force-generation potential, reduced spasticity, and improved quality of life.

FES leg cycling exercise is a physical activity that has potential to provide aerobic fitness and cardiovascular health benefits for individuals with SCI. However, there are few high-quality studies or systematic reviews for sufficient Level I or Level II evidence supporting the putative benefits of FES-evoked exercise after SCI, to make sound determination of its clinical efficacy to reduce obesity diabetes and cardiovascular disease. This paper samples some of the recent evidence supporting FES lower-limb exercise, by itself, and makes recommendations about how “critical dose-potency” might be achieved to provide clinical and health benefits from FES-exercise.

The aim of this study was to determine the efficacy and the effects of functional electrical stimulated cycling (FES cycling) in patients with spinal cord injury during their rehabilitation in a special acute care unit. Thirty patients [10 with American Spinal Injury Association Impairment Scale (AIS) grade A, three with AIS grade B, 15 with AIS grade C, two with AIS grade D] aged 44±15.5 years and 2 (median) (interquartile range, 1.0-4.25) months after spinal cord injury were included in the study. The patients participated in a 20-min FES-cycling program 2 days per week for 4 weeks during their acute inpatient rehabilitation. The influence on muscle cross-section, muscle and leg circumference, spasticity, and the walking ability parameter (distance, time, aids) was measured. Muscle stimulation intensity and output parameters (pedalling time and distance) were also recorded. Spasticity decreased during hip abduction and adduction (70 and 98.1%, respectively). Spasticity during knee flexion and knee extension decreased by 66.8 and 76.6%, and a decrease was found during dorsal foot extension (67.8%; for all, P<0.05). Presession-postsession comparisons showed that after 4 weeks of FES cycling, an increase in the circumference of the cross-sectional area of 15.3% on the left and of 17% on the right m. rectus femoris could be observed in group AIS A+B. In the AIS C+D group, the circumference of the left m. rectus femoris increased by 25% and that of the right m. rectus femoris by 21% (for all, P<0.05). The results of the study show that FES cycling in combination with function-oriented physiotherapy and occupational therapy can have a positive influence on spasticity, walking ability, and muscular reactivation. It seems to support circulatory processes within the rehabilitation of paraplegics already after a 4-week intervention.

A low cost clinical exercise system was developed for the spinal cord injured, based on a bicycle ergometer and electrical stimulation. A pilot project was conducted, using the system, to examine the effects of stimulation induced cycling in long term paraplegics. The project comprised 2 phases of exercise, a strengthening phase involving a 12 week programme of electrical stimulation to the quadriceps and hamstrings and a 12 week cycling phase. Physiological, morphological and biochemical parameters were measured for each subject, at the beginning of the programme and following each phase. Results showed that a programme of stimulation induced lower limb exercise increased the exercise tolerance of all patients, as determined by a progressive increase in exercise time, cycling rate and exercise load. The enhanced exercise tolerance was a result of increases in local muscle strength and endurance. Increases in thigh muscle area and joint range of motion were recorded and all incomplete subjects reported an improvement in functional capabilities and general wellbeing.

Twelve patients were involved in a 3 month stimulation induced cycling programme at the Royal Perth Rehabilitation Hospital. A number of the patients were less than 1 year post injury, all except one had an incomplete injury, and most were receiving physiotherapy. All patients who completed the programme increased their time of cycling and, in all but one case, the exercise load, indicative of a local training effect. Significant improvements were found in voluntary isometric strength, stimulated isometric strength and stimulated isometric endurance of the quadriceps, muscle grading of the quadriceps and biceps femoris and the cross-sectional areas of the quadriceps and total thigh muscle. No change was found in voluntary isokinetic strength of the quadriceps. All patients with incomplete injuries reported improvements in the activities of daily living (ADL) after the programme. Bone mineral density (BMD) was examined in two patients, one less than 1 year post injury, and one greater than 4 years post injury. The programme of cycling did not restore BMD in the latter patient. However, while the former patient still displayed a reduced BMD after the programme, it is unknown whether this loss of bone was retarded. This needs further investigation. This study demonstrates the effectiveness of a combined physiotherapy/cycling programme in the rehabilitation of people with spinal injuries. To be successful this type of programme has to be incorporated into the rehabilitation process, as has been done at the Sir George Bedbrook Spinal Unit.

Eight males with spinal cord injury (SCI) participated in an exercise training program using neuromuscular electrical stimulation (NMES) leg cycle ergometry. Each subject completed a minimum of 24 (mean +/- SD = 38.1 +/- 17.2) 30-minute training sessions over a 19-week period. The initial work rate (WR) of 0 watts (W) of unloaded cycling was increased when appropriate with subjects exercising at 11.4 +/- 3.7 W (range = 6.1 W-18.3 W) at the end of the training program. Randomized block repeated measures ANOVA was used to compare pretraining and posttraining peak physiologic responses during graded NMES leg cycle tests and subpeak physiologic responses during 10 minutes of NMES leg cycle exercise at an absolute WR (0 W). A significant (P < or = 0.05) increase was observed for peak VO2; (+10%, 1.29 +/- 0.30 to 1.42 +/- 0.39 1.min-1). No other statistically significant differences were noted for any other peak variable (VCO2, VO2 ml.kg-1 min-1, VE, WR, HR, RER) pre- to posttraining. During submaximal NMES leg cycle testing, a significant decrease was noted for RER (-9.2%, 1.19 +/- 0.14 to 1.08 +/- 0.09). No other submaximal variable (VO2 1.min-1, ml.kg-1.min-1, VCO2, HR, VE) showed significant changes as a result of the training. Although the improvement in peak VO2 was not as dramatic as those reported in previous studies, it appears that NMES leg cycle training performed two times per week can significantly enhance cardiorespiratory fitness.

To investigate whether exercise training can produce increases in bone mass in spinal cord-injured (SCI) individuals with established disuse osteopenia, nine subjects (age 28.2 years, time since injury 6.0 years, level of injury C5-T7) were recruited for a 9-month training program using functional electrical stimulation cycle ergometry (FES-CE), which produces active muscle contractions in the paralyzed limb. After training, bone mineral density (BMD, by X-ray absorptiometry) increased by 0.047 +/- 0.010 g/cm2 at the lumbar spine; changes in BMD at the femoral neck, distal femur, and proximal tibia were not significant for the group as a whole. In a subset of subjects training at > or = 18 W for at least 3 months (n = 4), BMD increased by 0.095 +/- 0.026 g/cm2 (+18%) at the distal femur. By 6 months of training, a 78% increase in serum osteocalcin was observed, indicating an increase in bone turnover. Urinary calcium and hydroxyproline, indicators of resorptive activity, did not change over the same period. Serum PTH increased 75% over baseline values (from 2.98 +/- 0.15 to 5.22 +/- 0.62 pmol/L) after 6 months’ training, with several individual values in hyperparathyroid range; PTH declined toward baseline values by 9 months. These data establish the feasibility of stimulating site-specific increases in bone mass in severely osteopenic bone with muscle contractions independent of weight-bearing for those subjects able to achieve a threshold power output of 18 W with FES-CE. Calcium supplementation from the outset of training in osteopenic individuals may be advisable to prevent training-induced increases in PTH.

OBJECTIVE: To determine the magnitude of changes in muscle mass and lower extremity body composition that could be induced with a regular regimen of functional electrical stimulation (FES)-induced lower-extremity cycling, as well as the distribution of changes in muscle mass among the thigh muscles in persons with spinal cord injury (SCI).

STUDY DESIGN: Thirteen men with neurologically complete motor sensory SCI underwent a 3-phase, FES-induced, ergometry exercise program: phase 1, quadriceps strengthening: phase 2, progressive sequential stimulation to achieve a rhythmic pedaling motion (surface electrodes placed over the quadriceps, hamstrings, and gluteal muscles); phase 3, FES-induced cycling for 30 minutes. Participants moved from one phase to the next when they met the objectives for the current phase.

MEASURES: Computed tomography of legs to assess muscle cross-sectional area and proportion of muscle and adipose tissue. Scans were done at baseline (before subjects started the program), at first follow-up, typically after 65.4+/-5.6 (SD) weekly sessions, and at second follow-up, typically after 98.1+/-9.1 sessions.

RESULTS: Increases in cross-sectional areas were found in the following muscles: rectus femoris (31%, p<.001). sartorius (22%, p<.025), adductor magnus-hamstrings (26%, p<.001), vastus lateralis (39%, p = .001), vastus medialis-intermedius (31%, p = .025). Cross-sectional area of adductor longus and gracilis muscles did not change. The ratio of muscle to adipose tissue increased significantly in thighs and calves. There was no correlation among the total number of exercise sessions and the magnitude of muscle hypertrophy.

CONCLUSIONS: Muscle cross-sectional area and the muscle to adipose tissue ratio of the lower extremities increased during a regular regimen of 2.3 FES-induced lower extremity cycling sessions weekly. The distribution of changes was related to the proximity of muscles to the stimulating electrodes.

STUDY DESIGN: Single subject pilot.

OBJECTIVES: (i) To see whether strength and endurance for recreational cycling by functional electrical stimulation (FES) are possible following spinal cord injury (SCI). (ii) To develop the equipment for FES-cycling.

SETTING: England.

METHODS: Near-isometric or cycling exercise was performed by the incomplete SCI subject at home.

RESULTS: After training for an average of 21 min per day for 16 months, the stimulated muscles increased in size and the subject was able to cycle for 12 km on the level. Surprisingly, there was a substantial increase in the measured voluntary strength of the knee extensors and the subject reports improved leg function.

CONCLUSION: FES-cycling may promote recovery after incomplete spinal cord injury. If so, it offers the possibility of being a convenient method for widespread use.

The authors of this prospective, single-case study evaluated the potential for functional recovery from chronic spinal cord injury (SCI). The patient was motor complete with minimal and transient sensory perception in the left hemibody. His condition was classified as C-2 American Spinal Injury Association (ASIA) Grade A and he had experienced no substantial recovery in the first 5 years after traumatic SCI. Clinical experience and evidence from the scientific literature suggest that further recovery would not take place. When the study began in 1999, the patient was tetraplegic and unable to breathe without assisted ventilation; his condition classification persisted as C-2 ASIA Grade A. Magnetic resonance imaging revealed severe injury at the C-2 level that had left a central fluid-filled cyst surrounded by a narrow donutlike rim of white matter. Five years after the injury a program known as “activity-based recovery” was instituted. The hypothesis was that patterned neural activity might stimulate the central nervous system to become more functional, as it does during development. Over a 3-year period (5-8 years after injury), the patient’s condition improved from ASIA Grade A to ASIA Grade C, an improvement of two ASIA grades. Motor scores improved from 0/100 to 20/100, and sensory scores rose from 5-7/112 to 58-77/112. Using electromyography, the authors documented voluntary control over important muscle groups, including the right hemidiaphragm (C3-5), extensor carpi radialis (C-6), and vastus medialis (L2-4). Reversal of osteoporosis and an increase in muscle mass was associated with this recovery. Moreover, spasticity decreased, the incidence of medical complications fell dramatically, and the incidence of infections and use of antibiotic medications was reduced by over 90%. These improvements occurred despite the fact that less than 25 mm2 of tissue (approximately 25%) of the outer cord (presumably white matter) had survived at the injury level. The primary novelty of this report is the demonstration that substantial recovery of function (two ASIA grades) is possible in a patient with severe C-2 ASIA Grade A injury, long after the initial SCI. Less severely injured (lower injury level, clinically incomplete lesions) individuals might achieve even more meaningful recovery. The role of patterned neural activity in regeneration and recovery of function after SCI therefore appears a fruitful area for future investigation.

Two years of functional electrical stimulation cycling (FESC) as a researcher and subject have given me an insight into the direction that future FESC should take as well as providing me with significant health benefits and an enjoyable and functional ability to cycle. If FESC is to benefit spinal cord injured persons (SCIPs), researchers must turn their attention to making the activity convenient and enjoyable. What follows is a personal view and will be less scientifically rigorous than other presentations but hopefully still of value. It calls upon my experience as a general medical practitioner with a special interest in the value of exercise, a human powered vehicle enthusiast, an amateur FES researcher, but most importantly, an SCIP and FES cyclist.

Functional electrical stimulation (FES)-induced leg exercise offers the potential for individuals with lower-limb paralysis to otherwise gain some benefits conferred by leg exercise. Although its original intent is to reactivate the leg muscles to produce functional upright mobility, as a rehabilitation therapy, FES-evoked exercise increases the whole-body metabolism of individuals with spinal cord injury (SCI) so that they may gain general and localized health and fitness benefits. The physiological and psychosocial responses during FES-evoked cycling, standing, rowing, leg extension, or stepping have been extensively explored for over 20 years. Some of the advantages of such exercise include augmented cardiorespiratory fitness, promotion of leg blood circulation, increased activity of specific metabolic enzymes or hormones, greater muscle volume and fiber size, enhanced functional exercise capacity such as strength and endurance, and altered bone mineral density. Positive psychosocial adaptations have also been reported among SCI individuals who undergo FES exercise. This article presents a position review of the available literature on the effects of FES-evoked exercise since the earliest date until 2007, to warrant a conclusion about the current status and potential of FES-evoked exercise for paralyzed people.

Inactivity and muscular adaptations following spinal cord injury (SCI) result in secondary complications such as cardiovascular disease, obesity, and pressure sores. Functional electrically stimulated (FES) cycling can potentially reduce these complications, but previous studies have provided inconsistent results. We studied the effect of intensive long-term FES cycle training on muscle properties in 11 SCI subjects (mean +/- SEM: 41.8 +/- 2.3 years) who had trained for up to 1 hour/day, 5 days/week, for 1 year. Comparative measurements were made in 10 able-bodied (AB) subjects. Quadriceps maximal electrically stimulated torque increased fivefold (n = 5), but remained lower than in AB individuals. Relative force response at 1 HZ decreased, relaxation rate remained unchanged, and fatigue resistance improved significantly. Power output (PO) improved to a lesser extent than quadriceps torque and not to a greater extent than has been reported previously. We need to understand the factors that limit PO in order to maximize the benefits of FES cycling.

Functional electrical stimulation (FES) cycling ergometer has been utilized in recent decades for rehabilitation by sequentially stimulating the large leg-actuating muscles of paralyzed leg muscles to produce cyclical leg motion. A number of studies reported physiological adaptations after regular FES-cycling exercise (FESCE) training in subjects with spinal cord injury, stroke, cerebral palsy and other conditions. This article provides a comprehensive overview of general aspects of FES cycling systems and clinical applications of FESCE. The studies cited in this article provide supportive findings for the potential clinical efficacy of FESCE for reducing the risk of secondary medical complications in subjects with paralysis. The potential therapeutic benefits of FESCE include conditioning the cardiopulmonary, muscular, and skeletal systems, and improving other physiological and psychological performances. Our recent pilot study also indicated that the decrease of leg spasticity in subjects with cerebral palsy is one of the acute effects of FESCE. In conclusion, we recommend that FESCE is of benefit in a variety of aspects to improve the general condition and to prevent deterioration in subjects with central neurological impairments.

OBJECTIVE: To investigate the long-term effects of functional electrical stimulation (FES)-evoked cycle training cadence on leg muscle hypertrophy and electrically evoked strength.

DESIGN: Open intervention study.

SETTING: Laboratory setting.

PARTICIPANTS: Untrained individuals with chronic spinal cord injury (N=8).

INTERVENTIONS: Six weeks (3d/wk) of training on an isokinetic FES cycle ergometer. For each subject, 1 leg was randomly allocated to cycling at 10 revolutions per minute (rpm) (LOW) for 30min/d, and the other cycling at 50rpm (HIGH) for 30min/d.

MAIN OUTCOME MEASURES: Pre- and posttraining measurements of lower limb circumference were performed at the distal and middle position of each thigh. Electrically evoked quadriceps muscle torque during an isometric contraction was also assessed.

RESULTS: Six weeks of FES cycle training significantly increased thigh girth in both LOW and HIGH groups. At midthigh, girth increases induced by LOW (6.6%±1.2%) were significantly greater than those by HIGH (3.6%±0.8%). LOW also produced greater gains in electrically evoked isometric torque than HIGH after training.

CONCLUSIONS: These results suggest that lower pedaling cadences evoke greater muscle hypertrophy and electrically stimulated muscle strength compared with higher cadences.

OBJECTIVE: To examine the effect of long-term lower extremity functional electrical stimulation (FES) cycling on the physical integrity and functional recovery in people with chronic spinal cord injury (SCI).

DESIGN: Retrospective cohort, mean follow-up 29.1 months, and cross-sectional evaluation.

SETTING: Washington University Spinal Cord Injury Neurorehabilitation Center, referral center.

PARTICIPANTS: Twenty-five people with chronic SCI who received FES during cycling were matched by age, gender, injury level, and severity, and duration of injury to 20 people with SCI who received range of motion and stretching.

INTERVENTION: Lower extremity FES during cycling as part of an activity-based restorative treatment regimen.

MAIN OUTCOME MEASURE: Change in neurological function: motor, sensory, and combined motor-sensory scores (CMSS) assessed by the American Spinal Injury Association Impairment scale. Response was defined as ≥ 1 point improvement.

RESULTS: FES was associated with an 80% CMSS responder rate compared to 40% in controls. An average 9.6 CMSS point loss among controls was offset by an average 20-point gain among FES subjects. Quadriceps muscle mass was on average 36% higher and intra/inter-muscular fat 44% lower, in the FES group. Hamstring and quadriceps muscle strength was 30 and 35% greater, respectively, in the FES group. Quality of life and daily function measures were significantly higher in FES group.

CONCLUSION: FES during cycling in chronic SCI may provide substantial physical integrity benefits, including enhanced neurological and functional performance, increased muscle size and force-generation potential, reduced spasticity, and improved quality of life.

A low cost clinical exercise system was developed for the spinal cord injured, based on a bicycle ergometer and electrical stimulation. A pilot project was conducted, using the system, to examine the effects of stimulation induced cycling in long term paraplegics. The project comprised 2 phases of exercise, a strengthening phase involving a 12 week programme of electrical stimulation to the quadriceps and hamstrings and a 12 week cycling phase. Physiological, morphological and biochemical parameters were measured for each subject, at the beginning of the programme and following each phase. Results showed that a programme of stimulation induced lower limb exercise increased the exercise tolerance of all patients, as determined by a progressive increase in exercise time, cycling rate and exercise load. The enhanced exercise tolerance was a result of increases in local muscle strength and endurance. Increases in thigh muscle area and joint range of motion were recorded and all incomplete subjects reported an improvement in functional capabilities and general well being.

Endurance for dynamic exercise, cardiac output, blood pressure, heart rate, ventilation, and oxygen consumption was measured in eight individuals with paraplegia at the end of 4-min bouts of exercise on a friction braked cycle ergometer. Movement of the subjects’ legs was induced by electrically stimulating the quadriceps, gluteus maximus and hamstring muscles with a computer-controlled biphasic square — wave current at a frequency of 30 Hz. The friction braked cycle ergometer was pedalled at work rates which varied between 0 and 40 W. Measurements were repeated after 3 and 6 months to assess the affect of training. After 3 months of training it was found that endurance increased from 8 min at a work rate of 0 W to 30 min at a work rate of 40 W. Compared to the cardiovascular responses in non-paralyzed subjects, computerized cycle ergometry was found to be associated with higher relative stresses for a given level of absolute work. Mean blood pressure, for example, increased by over 30% during maximal work in individuals with paralysis compared to the typical response obtained for able-bodied subjects. Analysis of the data showed that instead of the 20-30% metabolic efficiency commonly reported for cycle ergometry, the calculated metabolic efficiency during computer-controlled cycle ergometry was only 3.6%.

A group of 37 spinal cord injured (SCI) patients underwent bone density measurements at the distal and proximal end of the tibia by a special computed tomography scanner, the OsteoQuant. Fifteen of these patients had follow-up measurements while enrolled in a lower-limb exercise training program with functional electrical stimulation (FES). The pre-exercise measurements revealed a strong correlation (0.88 < or = r < or = 0.90) of trabecular, subcortical, and cortical bone density between the distal and proximal ends of the tibia. The expected bone density loss during the first two years post injury (as calculated from the regression lines of bone density vs. time post injury) amounted to 51.5% for trabecular, 44.2% for subcortical, and 32.7% for cortical bone. No major bone density loss was calculated after 7 years post injury. Analysis of the bone density data during the FES exercise program revealed various degrees of loss. However, the rate of bone loss for this FES exercise group was less than expected from the regression lines. The reduction of bone loss was between 0.2 and 3.3% per year, and was significant (p < 0.05) for all bone parameters at the distal end and for trabecular bone density at the proximal end of the tibia. These bone density measurements revealed a potentially positive effect of FES exercise intervention for the rehabilitation of SCI patients.

Twelve patients were involved in a 3 month stimulation induced cycling programme at the Royal Perth Rehabilitation Hospital. A number of the patients were less than 1 year post injury, all except one had an incomplete injury, and most were receiving physiotherapy. All patients who completed the programme increased their time of cycling and, in all but one case, the exercise load, indicative of a local training effect. Significant improvements were found in voluntary isometric strength, stimulated isometric strength and stimulated isometric endurance of the quadriceps, muscle grading of the quadriceps and biceps femoris and the cross-sectional areas of the quadriceps and total thigh muscle. No change was found in voluntary isokinetic strength of the quadriceps. All patients with incomplete injuries reported improvements in the activities of daily living (ADL) after the programme. Bone mineral density (BMD) was examined in two patients, one less than 1 year post injury, and one greater than 4 years post injury. The programme of cycling did not restore BMD in the latter patient. However, while the former patient still displayed a reduced BMD after the programme, it is unknown whether this loss of bone was retarded. This needs further investigation. This study demonstrates the effectiveness of a combined physiotherapy/cycling programme in the rehabilitation of people with spinal injuries. To be successful this type of programme has to be incorporated into the rehabilitation process, as has been done at the Sir George Bedbrook Spinal Unit.

Eight males with spinal cord injury (SCI) participated in an exercise training program using neuromuscular electrical stimulation (NMES) leg cycle ergometry. Each subject completed a minimum of 24 (mean +/- SD = 38.1 +/- 17.2) 30-minute training sessions over a 19-week period. The initial work rate (WR) of 0 watts (W) of unloaded cycling was increased when appropriate with subjects exercising at 11.4 +/- 3.7 W (range = 6.1 W-18.3 W) at the end of the training program. Randomized block repeated measures ANOVA was used to compare pretraining and posttraining peak physiologic responses during graded NMES leg cycle tests and subpeak physiologic responses during 10 minutes of NMES leg cycle exercise at an absolute WR (0 W). A significant (P < or = 0.05) increase was observed for peak VO2; (+10%, 1.29 +/- 0.30 to 1.42 +/- 0.39 1.min-1). No other statistically significant differences were noted for any other peak variable (VCO2, VO2 ml.kg-1 min-1, VE, WR, HR, RER) pre- to posttraining. During submaximal NMES leg cycle testing, a significant decrease was noted for RER (-9.2%, 1.19 +/- 0.14 to 1.08 +/- 0.09). No other submaximal variable (VO2 1.min-1, ml.kg-1.min-1, VCO2, HR, VE) showed significant changes as a result of the training. Although the improvement in peak VO2 was not as dramatic as those reported in previous studies, it appears that NMES leg cycle training performed two times per week can significantly enhance cardiorespiratory fitness.

To investigate whether exercise training can produce increases in bone mass in spinal cord-injured (SCI) individuals with established disuse osteopenia, nine subjects (age 28.2 years, time since injury 6.0 years, level of injury C5-T7) were recruited for a 9-month training program using functional electrical stimulation cycle ergometry (FES-CE), which produces active muscle contractions in the paralyzed limb. After training, bone mineral density (BMD, by X-ray absorptiometry) increased by 0.047 +/- 0.010 g/cm2 at the lumbar spine; changes in BMD at the femoral neck, distal femur, and proximal tibia were not significant for the group as a whole. In a subset of subjects training at > or = 18 W for at least 3 months (n = 4), BMD increased by 0.095 +/- 0.026 g/cm2 (+18%) at the distal femur. By 6 months of training, a 78% increase in serum osteocalcin was observed, indicating an increase in bone turnover. Urinary calcium and hydroxyproline, indicators of resorptive activity, did not change over the same period. Serum PTH increased 75% over baseline values (from 2.98 +/- 0.15 to 5.22 +/- 0.62 pmol/L) after 6 months’ training, with several individual values in hyperparathyroid range; PTH declined toward baseline values by 9 months. These data establish the feasibility of stimulating site-specific increases in bone mass in severely osteopenic bone with muscle contractions independent of weight-bearing for those subjects able to achieve a threshold power output of 18 W with FES-CE. Calcium supplementation from the outset of training in osteopenic individuals may be advisable to prevent training-induced increases in PTH.

OBJECTIVES: To determine if a hybrid exercise (leg plus arm) training program performed immediately after functional electrical stimulation (FES) leg cycle exercise (LCE) training would further improve aerobic capacity when compared with FES leg cycle training alone, and (2) to compare the submaximal responses occurring during both FES-LCE alone and hybrid exercise in the same SCI subjects.

DESIGN: Nonrandomized control trial whereby subjects act as their own control.

SETTING: Outpatient rehabilitation in a primary care hospital.

PATIENTS: A volunteer sample (n = 11) of men 20 to 50 years old with complete spinal cord injury, free from cardiovascular and metabolic disease with spasticity.

INTERVENTIONS: Three phases of exercise training: phase I, progressive FES-LCE to 30 minutes of exercise (n = 11); phase II, 35.2 +/- 16.2 sessions of FES-LCE (n = 11); phase III, 41.4 +/- 17.7 30-minute sessions of hybrid exercise (n = 8).

MAIN OUTCOME MEASURES: Aerobic capacity-a further increase after hybrid exercise when compared with FES-LCE alone; (2) submaximal physiologic parameters (oxygen uptake [VO2], heart rate [HR], blood lactate [BLa-])-measurement of these during constant work rate exercise and a training effect.

RESULTS: VO2 (the body’s ability to utilize oxygen) significantly improved (p < .05) after both FES-LCE and then further after hybrid training. Hybrid exercise training resulted in significantly (p < .05) greater work rates and VO2 values than both FES-LCE at baseline and training work rates.

CONCLUSION: These subjects demonstrated that hybrid exercise performed twice a week provided sufficient intensity to improve aerobic capacity and provide a medium whereby patients with SCI can burn more calories than via FES-LCE alone. This has important implications for improving the health and fitness levels of individuals with SCI and may ultimately reduce their risk of cardiovascular disease.

STUDY DESIGN: Longitudinal training.

OBJECTIVES: To determine the effects of functional electrical stimulated (FES) leg cycle ergometer training on muscle histochemical characteristics in individuals with motor-complete spinal cord injury (SCI).

SETTING: University of Alberta, Edmonton, Alberta, Canada.

METHODS: Six individuals with motor-complete SCI (age 31-50 years; 3-25 years post-injury) trained using FES leg cycle ergometry for 30 min, 3 days per week for 8 weeks. Biopsies of the vastus lateralis muscle were obtained pre- and post-training and analyzed for fibre composition, fibre size and capillarization.

RESULTS: The majority of muscle fibres were classified as type 2 pre- and post-training. Average fibre area increased 23% (P<0.05) and capillary number increased 39% (P<0.05) with training. As a result of these proportional increases, capillarizatio expressed relative to fibre area was unchanged with training.

CONCLUSIONS: FES leg cycle ergometer training results in proportional increases in fibre area and capillary number in individuals with SCI.

OBJECTIVE: To determine the magnitude of changes in muscle mass and lower extremity body composition that could be induced with a regular regimen of functional electrical stimulation (FES)-induced lower-extremity cycling, as well as the distribution of changes in muscle mass among the thigh muscles in persons with spinal cord injury (SCI).

STUDY DESIGN: Thirteen men with neurologically complete motor sensory SCI underwent a 3-phase, FES-induced, ergometry exercise program: phase 1, quadriceps strengthening: phase 2, progressive sequential stimulation to achieve a rhythmic pedaling motion (surface electrodes placed over the quadriceps, hamstrings, and gluteal muscles); phase 3, FES-induced cycling for 30 minutes. Participants moved from one phase to the next when they met the objectives for the current phase.

MEASURES: Computed tomography of legs to assess muscle cross-sectional area and proportion of muscle and adipose tissue. Scans were done at baseline (before subjects started the program), at first follow-up, typically after 65.4+/-5.6 (SD) weekly sessions, and at second follow-up, typically after 98.1+/-9.1 sessions.

RESULTS: Increases in cross-sectional areas were found in the following muscles: rectus femoris (31%, p<.001). sartorius (22%, p<.025), adductor magnus-hamstrings (26%, p<.001), vastus lateralis (39%, p = .001), vastus medialis-intermedius (31%, p = .025). Cross-sectional area of adductor longus and gracilis muscles did not change. The ratio of muscle to adipose tissue increased significantly in thighs and calves. There was no correlation among the total number of exercise sessions and the magnitude of muscle hypertrophy.

CONCLUSIONS: Muscle cross-sectional area and the muscle to adipose tissue ratio of the lower extremities increased during a regular regimen of 2.3 FES-induced lower extremity cycling sessions weekly. The distribution of changes was related to the proximity of muscles to the stimulating electrodes.

STUDY DESIGN: Single subject pilot.

OBJECTIVES: (i) To see whether strength and endurance for recreational cycling by functional electrical stimulation (FES) are possible following spinal cord injury (SCI). (ii) To develop the equipment for FES-cycling.

SETTING: England.

METHODS: Near-isometric or cycling exercise was performed by the incomplete SCI subject at home.

RESULTS: After training for an average of 21 min per day for 16 months, the stimulated muscles increased in size and the subject was able to cycle for 12 km on the level. Surprisingly, there was a substantial increase in the measured voluntary strength of the knee extensors and the subject reports improved leg function.

CONCLUSION: FES-cycling may promote recovery after incomplete spinal cord injury. If so, it offers the possibility of being a convenient method for widespread use.

OBJECTIVE: To test whether a short period of training leads to adaptations in the cross-sectional area of large conduit arteries and improved blood flow to the paralyzed legs of individuals with spinal cord injury (SCI).

DESIGN: Before-after trial.

SETTING: Rehabilitation center, academic medical center.

PARTICIPANTS: Nine men with spinal cord lesions.

INTERVENTION: Six weeks of cycling using a functional electrically stimulated leg cycle ergometer (FES-LCE).

MAIN OUTCOME MEASURES: Longitudinal images and simultaneous velocity spectra were measured in the common carotid (CA) and femoral (FA) arteries using quantitative duplex Doppler ultrasound examination. Arterial diameters, peak systolic inflow volumes (PSIVs), mean inflow volumes (MIVs), and a velocity index (VI), representing the peripheral resistance, were obtained at rest. PSIVs and VI were obtained during 3 minutes of hyperemia following 20 minutes of FA occlusion.

RESULTS: Training resulted in significant increases in diameter (p < .01), PSIVs (p < .01), and MIVs (p < .05), and reduced VI (p < .01) of the FA, whereas values in the CA remained unchanged. Postocclusive hyperemic responses were augmented, indicated by significantly higher PSIVs (p <.01) and a trend toward lower VI.

CONCLUSION: Six weeks of FES-LCE training increased the cross-sectional area of large conduit arteries and improved blood flow to the paralyzed legs of individuals with SCI.

The purpose of the present study was to determine the effect of a spinal cord injury (SCI) on resting vascular resistance in paralyzed legs in humans. To accomplish this goal, we measured blood pressure and resting flow above and below the lesion (by using venous occlusion plethysmography) in 11 patients with SCI and in 10 healthy controls (C). Relative vascular resistance was calculated as mean arterial pressure in millimeters of mercury divided by the arterial blood flow in milliliters per minute per 100 milliliters of tissue. Arterial blood flow in the sympathetically deprived and paralyzed legs of SCI was significantly lower than leg blood flow in C. Because mean arterial pressure showed no differences between both groups, leg vascular resistance in SCI was significantly higher than in C. Within the SCI group, arterial blood flow was significantly higher and vascular resistance significantly lower in the arms than in the legs. To distinguish between the effect of loss of central neural control vs. deconditioning, a group of nine SCI patients was trained for 6 wk and showed a 30% increase in leg blood flow with unchanged blood pressure levels, indicating a marked reduction in vascular resistance. In conclusion, vascular resistance is increased in the paralyzed legs of individuals with SCI and is reversible by training.

DESIGN: Longitudinal training.

OBJECTIVES: The purpose was to determine the effect of electrical stimulation (ES)-assisted cycling (30 min/day, 3 days/week for 8 weeks) on glucose tolerance and insulin sensitivity in people with spinal cord injury (SCI).

SETTING: The Steadward Centre, Alberta, Canada.

METHODS: Seven participants with motor complete SCI (five males and two females aged 30 to 53 years, injured 3-40 years, C5-T10) underwent 2-h oral glucose tolerance tests (OGTT, n=7) and hyperglycaemic clamp tests (n=3) before and after 8 weeks of training with ES-assisted cycling.

RESULTS: Results indicated that subjects’ glucose level were significantly lower at 2 h OGTT following 8 weeks of training (122.4+/-10 vs 139.9+/-16, P=0.014). Two-hour hyperglycaemic clamps tests showed improvement in all three people for glucose utilisation and in two of three people for insulin sensitivity.

CONCLUSIONS: These results suggested that exercise with ES-assisted cycling is beneficial for the prevention and treatment of Type 2 diabetes mellitus in people with SCI.

The authors of this prospective, single-case study evaluated the potential for functional recovery from chronic spinal cord injury (SCI). The patient was motor complete with minimal and transient sensory perception in the left hemibody. His condition was classified as C-2 American Spinal Injury Association (ASIA) Grade A and he had experienced no substantial recovery in the first 5 years after traumatic SCI. Clinical experience and evidence from the scientific literature suggest that further recovery would not take place. When the study began in 1999, the patient was tetraplegic and unable to breathe without assisted ventilation; his condition classification persisted as C-2 ASIA Grade A. Magnetic resonance imaging revealed severe injury at the C-2 level that had left a central fluid-filled cyst surrounded by a narrow donutlike rim of white matter. Five years after the injury a program known as “activity-based recovery” was instituted. The hypothesis was that patterned neural activity might stimulate the central nervous system to become more functional, as it does during development. Over a 3-year period (5-8 years after injury), the patient’s condition improved from ASIA Grade A to ASIA Grade C, an improvement of two ASIA grades. Motor scores improved from 0/100 to 20/100, and sensory scores rose from 5-7/112 to 58-77/112. Using electromyography, the authors documented voluntary control over important muscle groups, including the right hemidiaphragm (C3-5), extensor carpi radialis (C-6), and vastus medialis (L2-4). Reversal of osteoporosis and an increase in muscle mass was associated with this recovery. Moreover, spasticity decreased, the incidence of medical complications fell dramatically, and the incidence of infections and use of antibiotic medications was reduced by over 90%. These improvements occurred despite the fact that less than 25 mm2 of tissue (approximately 25%) of the outer cord (presumably white matter) had survived at the injury level. The primary novelty of this report is the demonstration that substantial recovery of function (two ASIA grades) is possible in a patient with severe C-2 ASIA Grade A injury, long after the initial SCI. Less severely injured (lower injury level, clinically incomplete lesions) individuals might achieve even more meaningful recovery. The role of patterned neural activity in regeneration and recovery of function after SCI therefore appears a fruitful area for future investigation.

Two years of functional electrical stimulation cycling (FESC) as a researcher and subject have given me an insight into the direction that future FESC should take as well as providing me with significant health benefits and an enjoyable and functional ability to cycle. If FESC is to benefit spinal cord injured persons (SCIPs), researchers must turn their attention to making the activity convenient and enjoyable. What follows is a personal view and will be less scientifically rigorous than other presentations but hopefully still of value. It calls upon my experience as a general medical practitioner with a special interest in the value of exercise, a human powered vehicle enthusiast, an amateur FES researcher, but most importantly, an SCIP and FES cyclist.

The effect of functional electrical stimulation (FES) training on body composition, assessed by computed tomography, and the effect of spasticity, assessed by both objective and subjective measures, are evaluated. Fifteen motor-complete spinal-cord-injured men participated in the study. Eight of the 15 subjects undertook FES cycling 3 times weekly for 6 months. Whole body computed tomography scans evaluated changes in body composition. Simultaneous Modified Ashworth Scale and electromyography (EMG) measurements, resistive torque (Kin-Com) and EMG measurements, and self-ratings with Visual Analogue Scale during four consecutive days were used to evaluate changes in spasticity. Lower extremity muscle volume increased by an average of 1300 cm3 (p < 0.001) in the training group compared to the control group, who experienced no change. Otherwise no changes in body composition were seen. Significant correlations (Spearman) were found between individual EMG activity recordings and movement-provoked Modified Ashworth Scale ratings in 26% of the test situations, irrespective of group and time. The objective and subjective evaluation of movement-provoked passive (viscoelastic) and active (spasticity-related) resistance remained unchanged.

The effect of early intervention using functional electric stimulation cycle ergometry (FES-CE) on skeletal muscle morphology was evaluated in traumatic spinal cord injured (SCI) patients 4 – 6 weeks after injury. Motor complete SCI patients (n = 10) were assigned to either a SCI control group (IC) or FES-CE group (IE) and compared to uninjured controls (UIC) matched for age, activity, and gender. Training via FES-CE was performed 3 days/week for 13 weeks. In the FES-CE trained group, power output increased from 2.4 ± 88 Watts to 24.5 ± 3.2 Watts. Muscle biopsies were taken from the vastus lateralis muscle at pre- and posttraining for subsequent morphological analysis. Without intervention, muscle fiber cross sectional area (CSAf ) decreased 38% and 65% at 6 and 19 weeks post-SCI, respectively. The loss of CSAf had no impact on myonuclear density. Following 13 weeks of FES-CE training, CSAf increased was 63% greater when compared to the IC group. Results of the present investigation suggest that the initiation of FES-CE in first weeks after traumatic SCI attenuates the loss of muscle mass and power output.

Inactivity and muscular adaptations following spinal cord injury (SCI) result in secondary complications such as cardiovascular disease, obesity, and pressure sores. Functional electrically stimulated (FES) cycling can potentially reduce these complications, but previous studies have provided inconsistent results. We studied the effect of intensive long-term FES cycle training on muscle properties in 11 SCI subjects (mean +/- SEM: 41.8 +/- 2.3 years) who had trained for up to 1 hour/day, 5 days/week, for 1 year. Comparative measurements were made in 10 able-bodied (AB) subjects. Quadriceps maximal electrically stimulated torque increased fivefold (n = 5), but remained lower than in AB individuals. Relative force response at 1 HZ decreased, relaxation rate remained unchanged, and fatigue resistance improved significantly. Power output (PO) improved to a lesser extent than quadriceps torque and not to a greater extent than has been reported previously. We need to understand the factors that limit PO in order to maximize the benefits of FES cycling.

Spinal cord injury (SCI) leads to severe bone loss in the paralysed limbs and to a resulting increased fracture risk thereof. Since long bone fractures can lead to comorbidities and a reduction in quality of life, it is important to improve bone strength in people with chronic SCI. In this prospective longitudinal cohort study, we investigated whether functional electrical stimulation (FES) induced high-volume cycle training can partially reverse the loss of bone substance in the legs after chronic complete SCI. Eleven participants with motor-sensory complete SCI (mean age 41.9+/-7.5 years; 11.0+/-7.1 years post injury) were recruited. After an initial phase of 14+/-7 weeks of FES muscle conditioning, participants performed on average 3.7+/-0.6 FES-cycling sessions per week, of 58+/-5 min each, over 12 months at each individual’s highest power output. Bone and muscle parameters were investigated in the legs by means of peripheral quantitative computed tomography before the muscle conditioning (t1), and after six (t2) and 12 months (t3) of high-volume FES-cycle training. After 12 months of FES-cycling, trabecular and total bone mineral density (BMD) as well as total cross-sectional area in the distal femoral epiphysis increased significantly by 14.4+/-21.1%, 7.0+/-10.8% and 1.2+/-1.5%, respectively. Bone parameters in the femoral shaft showed small but significant decreases, with a reduction of 0.4+/-0.4% in cortical BMD, 1.8+/-3.0% in bone mineral content, and 1.5+/-2.1% in cortical thickness. These decreases mainly occurred between t1 and t2. No significant changes were found in any of the measured bone parameters in the tibia. Muscle CSA at the thigh increased significantly by 35.5+/-18.3%, while fat CSA at the shank decreased by 16.7+/-12.3%. Our results indicate that high-volume FES-cycle training leads to site-specific skeletal changes in the paralysed limbs, with an increase in bone parameters at the actively loaded distal femur but not the passively loaded tibia. Thus, we conclude that high-volume FES-induced cycle training has clinical relevance as it can partially reverse bone loss and thus may reduce fracture risk at this fracture prone site.

Persons with spinal cord injury (SCI) are at a heightened risk of developing type II diabetes and cardiovascular disease. The purpose of this investigation was to conduct an analysis of metabolic, body composition, and neurological factors before and after 10 weeks of functional electrical stimulation (FES) cycling in persons with SCI. Eighteen individuals with SCI received FES cycling 2-3 times per week for 10 weeks. Body composition was analyzed by dual X-ray absorptiometry. The American Spinal Injury Association (ASIA) neurological classification of SCI test battery was used to assess motor and sensory function. An oral glucose tolerance (OGTT) and insulin-response test was performed to assess blood glucose control. Additional metabolic variables including plasma cholesterol (total-C, HDL-C, LDL-C), triglyceride, and inflammatory markers (IL-6, TNF-alpha, and CRP) were also measured. Total FES cycling power and work done increased with training. Lean muscle mass also increased, whereas, bone and adipose mass did not change. The ASIA motor and sensory scores for the lower extremity significantly increased with training. Blood glucose and insulin levels were lower following the OGTT after 10 weeks of training. Triglyceride levels did not change following training. However, levels of IL-6, TNF-alpha, and CRP were all significantly reduced.

OBJECTIVE: To determine the effect of cycling, electrical stimulation, or both, on thigh muscle volume and stimulated muscle strength in children with spinal cord injury (SCI).

DESIGN: Randomized controlled trial.

SETTING: Children’s hospital specializing in pediatric SCI.

PARTICIPANTS: Children (N=30; ages, 5-13y) with chronic SCI.

INTERVENTIONS: Children were randomly assigned to 1 of 3 interventions: functional electrical stimulation cycling (FESC), passive cycling (PC), and noncycling, electrically stimulated exercise (ES). Each group exercised for 1 hour, 3 times per week for 6 months at home.

MAIN OUTCOME MEASURES: Preintervention and postintervention, children underwent magnetic resonance imaging to assess muscle volume, and electrically stimulated isometric muscle strength testing with the use of a computerized dynamometer. Data were analyzed via analyses of covariance (ANCOVA) with baseline measures as covariates. Within-group changes were assessed via paired t tests.

RESULTS: All 30 children completed the training. Muscle volume data were complete for 24 children (8 FESC, 8 PC, 8 ES) and stimulated strength data for 27 children (9 per group). Per ANCOVA, there were differences between groups (P<.05) for quadriceps muscle volume and stimulated strength, with the ES group having greater changes in volume and the FESC group having greater changes in strength. Within-group analyses showed increased quadriceps volume and strength for the FESC group and increased quadriceps volume for the ES group.

CONCLUSIONS: Children receiving either electrically stimulated exercise experienced changes in muscle size, stimulated strength, or both. These changes may decrease their risk of cardiovascular disease, insulin resistance, glucose intolerance, and type 2 diabetes.

Functional electrical stimulation (FES) cycling ergometer has been utilized in recent decades for rehabilitation by sequentially stimulating the large leg-actuating muscles of paralyzed leg muscles to produce cyclical leg motion. A number of studies reported physiological adaptations after regular FES-cycling exercise (FESCE) training in subjects with spinal cord injury, stroke, cerebral palsy and other conditions. This article provides a comprehensive overview of general aspects of FES cycling systems and clinical applications of FESCE. The studies cited in this article provide supportive findings for the potential clinical efficacy of FESCE for reducing the risk of secondary medical complications in subjects with paralysis. The potential therapeutic benefits of FESCE include conditioning the cardiopulmonary, muscular, and skeletal systems, and improving other physiological and psychological performances. Our recent pilot study also indicated that the decrease of leg spasticity in subjects with cerebral palsy is one of the acute effects of FESCE. In conclusion, we recommend that FESCE is of benefit in a variety of aspects to improve the general condition and to prevent deterioration in subjects with central neurological impairments.

The aim of this study was to determine the efficacy and the effects of functional electrical stimulated cycling (FES cycling) in patients with spinal cord injury during their rehabilitation in a special acute care unit. Thirty patients [10 with American Spinal Injury Association Impairment Scale (AIS) grade A, three with AIS grade B, 15 with AIS grade C, two with AIS grade D] aged 44±15.5 years and 2 (median) (interquartile range, 1.0-4.25) months after spinal cord injury were included in the study. The patients participated in a 20-min FES-cycling program 2 days per week for 4 weeks during their acute inpatient rehabilitation. The influence on muscle cross-section, muscle and leg circumference, spasticity, and the walking ability parameter (distance, time, aids) was measured. Muscle stimulation intensity and output parameters (pedalling time and distance) were also recorded. Spasticity decreased during hip abduction and adduction (70 and 98.1%, respectively). Spasticity during knee flexion and knee extension decreased by 66.8 and 76.6%, and a decrease was found during dorsal foot extension (67.8%; for all, P<0.05). Presession-postsession comparisons showed that after 4 weeks of FES cycling, an increase in the circumference of the cross-sectional area of 15.3% on the left and of 17% on the right m. rectus femoris could be observed in group AIS A+B. In the AIS C+D group, the circumference of the left m. rectus femoris increased by 25% and that of the right m. rectus femoris by 21% (for all, P<0.05). The results of the study show that FES cycling in combination with function-oriented physiotherapy and occupational therapy can have a positive influence on spasticity, walking ability, and muscular reactivation. It seems to support circulatory processes within the rehabilitation of paraplegics already after a 4-week intervention.

Persons with spinal cord injury (SCI) are at a heightened risk of developing type II diabetes and cardiovascular disease. The purpose of this investigation was to conduct an analysis of metabolic, body composition, and neurological factors before and after 10 weeks of functional electrical stimulation (FES) cycling in persons with SCI. Eighteen individuals with SCI received FES cycling 2-3 times per week for 10 weeks. Body composition was analyzed by dual X-ray absorptiometry. The American Spinal Injury Association (ASIA) neurological classification of SCI test battery was used to assess motor and sensory function. An oral glucose tolerance (OGTT) and insulin-response test was performed to assess blood glucose control. Additional metabolic variables including plasma cholesterol (total-C, HDL-C, LDL-C), triglyceride, and inflammatory markers (IL-6, TNF-alpha, and CRP) were also measured. Total FES cycling power and work done increased with training. Lean muscle mass also increased, whereas, bone and adipose mass did not change. The ASIA motor and sensory scores for the lower extremity significantly increased with training. Blood glucose and insulin levels were lower following the OGTT after 10 weeks of training. Triglyceride levels did not change following training. However, levels of IL-6, TNF-alpha, and CRP were all significantly reduced.

A low cost clinical exercise system was developed for the spinal cord injured, based on a bicycle ergometer and electrical stimulation. A pilot project was conducted, using the system, to examine the effects of stimulation induced cycling in long term paraplegics. The project comprised 2 phases of exercise, a strengthening phase involving a 12 week programme of electrical stimulation to the quadriceps and hamstrings and a 12 week cycling phase. Physiological, morphological and biochemical parameters were measured for each subject, at the beginning of the programme and following each phase. Results showed that a programme of stimulation induced lower limb exercise increased the exercise tolerance of all patients, as determined by a progressive increase in exercise time, cycling rate and exercise load. The enhanced exercise tolerance was a result of increases in local muscle strength and endurance. Increases in thigh muscle area and joint range of motion were recorded and all incomplete subjects reported an improvement in functional capabilities and general wellbeing.

Twelve patients were involved in a 3 month stimulation induced cycling programme at the Royal Perth Rehabilitation Hospital. A number of the patients were less than 1 year post injury, all except one had an incomplete injury, and most were receiving physiotherapy. All patients who completed the programme increased their time of cycling and, in all but one case, the exercise load, indicative of a local training effect. Significant improvements were found in voluntary isometric strength, stimulated isometric strength and stimulated isometric endurance of the quadriceps, muscle grading of the quadriceps and biceps femoris and the cross-sectional areas of the quadriceps and total thigh muscle. No change was found in voluntary isokinetic strength of the quadriceps. All patients with incomplete injuries reported improvements in the activities of daily living (ADL) after the programme. Bone mineral density (BMD) was examined in two patients, one less than 1 year post injury, and one greater than 4 years post injury. The programme of cycling did not restore BMD in the latter patient. However, while the former patient still displayed a reduced BMD after the programme, it is unknown whether this loss of bone was retarded. This needs further investigation. This study demonstrates the effectiveness of a combined physiotherapy/cycling programme in the rehabilitation of people with spinal injuries. To be successful this type of programme has to be incorporated into the rehabilitation process, as has been done at the Sir George Bedbrook Spinal Unit.

STUDY DESIGN: Single subject pilot.

OBJECTIVES: (i) To see whether strength and endurance for recreational cycling by functional electrical stimulation (FES) are possible following spinal cord injury (SCI). (ii) To develop the equipment for FES-cycling.

SETTING: England.

METHODS: Near-isometric or cycling exercise was performed by the incomplete SCI subject at home.

RESULTS: After training for an average of 21 min per day for 16 months, the stimulated muscles increased in size and the subject was able to cycle for 12 km on the level. Surprisingly, there was a substantial increase in the measured voluntary strength of the knee extensors and the subject reports improved leg function.

CONCLUSION: FES-cycling may promote recovery after incomplete spinal cord injury. If so, it offers the possibility of being a convenient method for widespread use.

The authors of this prospective, single-case study evaluated the potential for functional recovery from chronic spinal cord injury (SCI). The patient was motor complete with minimal and transient sensory perception in the left hemibody. His condition was classified as C-2 American Spinal Injury Association (ASIA) Grade A and he had experienced no substantial recovery in the first 5 years after traumatic SCI. Clinical experience and evidence from the scientific literature suggest that further recovery would not take place. When the study began in 1999, the patient was tetraplegic and unable to breathe without assisted ventilation; his condition classification persisted as C-2 ASIA Grade A. Magnetic resonance imaging revealed severe injury at the C-2 level that had left a central fluid-filled cyst surrounded by a narrow donutlike rim of white matter. Five years after the injury a program known as “activity-based recovery” was instituted. The hypothesis was that patterned neural activity might stimulate the central nervous system to become more functional, as it does during development. Over a 3-year period (5-8 years after injury), the patient’s condition improved from ASIA Grade A to ASIA Grade C, an improvement of two ASIA grades. Motor scores improved from 0/100 to 20/100, and sensory scores rose from 5-7/112 to 58-77/112. Using electromyography, the authors documented voluntary control over important muscle groups, including the right hemidiaphragm (C3-5), extensor carpi radialis (C-6), and vastus medialis (L2-4). Reversal of osteoporosis and an increase in muscle mass was associated with this recovery. Moreover, spasticity decreased, the incidence of medical complications fell dramatically, and the incidence of infections and use of antibiotic medications was reduced by over 90%. These improvements occurred despite the fact that less than 25 mm2 of tissue (approximately 25%) of the outer cord (presumably white matter) had survived at the injury level. The primary novelty of this report is the demonstration that substantial recovery of function (two ASIA grades) is possible in a patient with severe C-2 ASIA Grade A injury, long after the initial SCI. Less severely injured (lower injury level, clinically incomplete lesions) individuals might achieve even more meaningful recovery. The role of patterned neural activity in regeneration and recovery of function after SCI therefore appears a fruitful area for future investigation.

Two years of functional electrical stimulation cycling (FESC) as a researcher and subject have given me an insight into the direction that future FESC should take as well as providing me with significant health benefits and an enjoyable and functional ability to cycle. If FESC is to benefit spinal cord injured persons (SCIPs), researchers must turn their attention to making the activity convenient and enjoyable. What follows is a personal view and will be less scientifically rigorous than other presentations but hopefully still of value. It calls upon my experience as a general medical practitioner with a special interest in the value of exercise, a human powered vehicle enthusiast, an amateur FES researcher, but most importantly, an SCIP and FES cyclist.

Persons with spinal cord injury (SCI) are at a heightened risk of developing type II diabetes and cardiovascular disease. The purpose of this investigation was to conduct an analysis of metabolic, body composition, and neurological factors before and after 10 weeks of functional electrical stimulation (FES) cycling in persons with SCI. Eighteen individuals with SCI received FES cycling 2-3 times per week for 10 weeks. Body composition was analyzed by dual X-ray absorptiometry. The American Spinal Injury Association (ASIA) neurological classification of SCI test battery was used to assess motor and sensory function. An oral glucose tolerance (OGTT) and insulin-response test was performed to assess blood glucose control. Additional metabolic variables including plasma cholesterol (total-C, HDL-C, LDL-C), triglyceride, and inflammatory markers (IL-6, TNF-alpha, and CRP) were also measured. Total FES cycling power and work done increased with training. Lean muscle mass also increased, whereas, bone and adipose mass did not change. The ASIA motor and sensory scores for the lower extremity significantly increased with training. Blood glucose and insulin levels were lower following the OGTT after 10 weeks of training. Triglyceride levels did not change following training. However, levels of IL-6, TNF-alpha, and CRP were all significantly reduced.

OBJECTIVE: To examine the effect of long-term lower extremity functional electrical stimulation (FES) cycling on the physical integrity and functional recovery in people with chronic spinal cord injury (SCI).

DESIGN: Retrospective cohort, mean follow-up 29.1 months, and cross-sectional evaluation.

SETTING: Washington University Spinal Cord Injury Neurorehabilitation Center, referral center.

PARTICIPANTS: Twenty-five people with chronic SCI who received FES during cycling were matched by age, gender, injury level, and severity, and duration of injury to 20 people with SCI who received range of motion and stretching.

INTERVENTION: Lower extremity FES during cycling as part of an activity-based restorative treatment regimen.

MAIN OUTCOME MEASURE: Change in neurological function: motor, sensory, and combined motor-sensory scores (CMSS) assessed by the American Spinal Injury Association Impairment scale. Response was defined as ≥ 1 point improvement.

RESULTS: FES was associated with an 80% CMSS responder rate compared to 40% in controls. An average 9.6 CMSS point loss among controls was offset by an average 20-point gain among FES subjects. Quadriceps muscle mass was on average 36% higher and intra/inter-muscular fat 44% lower, in the FES group. Hamstring and quadriceps muscle strength was 30 and 35% greater, respectively, in the FES group. Quality of life and daily function measures were significantly higher in FES group.

CONCLUSION: FES during cycling in chronic SCI may provide substantial physical integrity benefits, including enhanced neurological and functional performance, increased muscle size and force-generation potential, reduced spasticity, and improved quality of life.

FES leg cycling exercise is a physical activity that has potential to provide aerobic fitness and cardiovascular health benefits for individuals with SCI. However, there are few high-quality studies or systematic reviews for sufficient Level I or Level II evidence supporting the putative benefits of FES-evoked exercise after SCI, to make sound determination of its clinical efficacy to reduce obesity diabetes and cardiovascular disease. This paper samples some of the recent evidence supporting FES lower-limb exercise, by itself, and makes recommendations about how “critical dose-potency” might be achieved to provide clinical and health benefits from FES-exercise.

The aim of this study was to determine the efficacy and the effects of functional electrical stimulated cycling (FES cycling) in patients with spinal cord injury during their rehabilitation in a special acute care unit. Thirty patients [10 with American Spinal Injury Association Impairment Scale (AIS) grade A, three with AIS grade B, 15 with AIS grade C, two with AIS grade D] aged 44±15.5 years and 2 (median) (interquartile range, 1.0-4.25) months after spinal cord injury were included in the study. The patients participated in a 20-min FES-cycling program 2 days per week for 4 weeks during their acute inpatient rehabilitation. The influence on muscle cross-section, muscle and leg circumference, spasticity, and the walking ability parameter (distance, time, aids) was measured. Muscle stimulation intensity and output parameters (pedalling time and distance) were also recorded. Spasticity decreased during hip abduction and adduction (70 and 98.1%, respectively). Spasticity during knee flexion and knee extension decreased by 66.8 and 76.6%, and a decrease was found during dorsal foot extension (67.8%; for all, P<0.05). Presession-postsession comparisons showed that after 4 weeks of FES cycling, an increase in the circumference of the cross-sectional area of 15.3% on the left and of 17% on the right m. rectus femoris could be observed in group AIS A+B. In the AIS C+D group, the circumference of the left m. rectus femoris increased by 25% and that of the right m. rectus femoris by 21% (for all, P<0.05). The results of the study show that FES cycling in combination with function-oriented physiotherapy and occupational therapy can have a positive influence on spasticity, walking ability, and muscular reactivation. It seems to support circulatory processes within the rehabilitation of paraplegics already after a 4-week intervention.

STUDY DESIGN: Prospective single-arm study.

OBJECTIVES: To investigate the effect of functional electrical stimulation (FES) cycling on late functional recovery, spasticity, gait parameters and oxygen consumption during walking in patients with chronic incomplete spinal cord injury (SCI).

SETTING: Turkish Armed Forces Rehabilitation Center, Ankara, Turkey.

METHODS: Ten patients with chronic (duration of more than 2 years) incomplete SCI who could ambulate at least 10 m independently or with the assistance of a cane or walker, but no hip-knee-ankle-foot orthosis. The subjects underwent 1-h FES cycling sessions three times a week for 16 weeks. Outcome measures including the total motor score, the Functional Independence Measure (FIM) score, the Modified Ashworth Scale for knee spasticity, temporal spatial gait parameters and oxygen consumption rate during walking were assessed at baseline, 3 and 6 months after the baseline.

RESULTS: There were statistically significant improvements in total motor scores, the FIM scores and spasticity level at the 6-month follow-up (P<0.01). The changes in gait parameters reached no significant level (P>0.05). Oxygen consumption rate of the patients showed significant reduction at only 6 months compared with baseline (P<0.01).

CONCLUSION: The results suggest that FES cycling may provide some functional improvements in the late period of SCI.

A low cost clinical exercise system was developed for the spinal cord injured, based on a bicycle ergometer and electrical stimulation. A pilot project was conducted, using the system, to examine the effects of stimulation induced cycling in long term paraplegics. The project comprised 2 phases of exercise, a strengthening phase involving a 12 week programme of electrical stimulation to the quadriceps and hamstrings and a 12 week cycling phase. Physiological, morphological and biochemical parameters were measured for each subject, at the beginning of the programme and following each phase. Results showed that a programme of stimulation induced lower limb exercise increased the exercise tolerance of all patients, as determined by a progressive increase in exercise time, cycling rate and exercise load. The enhanced exercise tolerance was a result of increases in local muscle strength and endurance. Increases in thigh muscle area and joint range of motion were recorded and all incomplete subjects reported an improvement in functional capabilities and general wellbeing..

A low cost clinical exercise system was developed for the spinal cord injured, based on a bicycle ergometer and electrical stimulation. A pilot project was conducted, using the system, to examine the effects of stimulation induced cycling in long term paraplegics. The project comprised 2 phases of exercise, a strengthening phase involving a 12 week programme of electrical stimulation to the quadriceps and hamstrings and a 12 week cycling phase. Physiological, morphological and biochemical parameters were measured for each subject, at the beginning of the programme and following each phase. Results showed that a programme of stimulation induced lower limb exercise increased the exercise tolerance of all patients, as determined by a progressive increase in exercise time, cycling rate and exercise load. The enhanced exercise tolerance was a result of increases in local muscle strength and endurance. Increases in thigh muscle area and joint range of motion were recorded and all incomplete subjects reported an improvement in functional capabilities and general wellbeing.

Endurance for dynamic exercise, cardiac output, blood pressure, heart rate, ventilation, and oxygen consumption was measured in eight individuals with paraplegia at the end of 4-min bouts of exercise on a friction braked cycle ergometer. Movement of the subjects’ legs was induced by electrically stimulating the quadriceps, gluteus maximus and hamstring muscles with a computer-controlled biphasic square — wave current at a frequency of 30 Hz. The friction braked cycle ergometer was pedalled at work rates which varied between 0 and 40 W. Measurements were repeated after 3 and 6 months to assess the affect of training. After 3 months of training it was found that endurance increased from 8 min at a work rate of 0 W to 30 min at a work rate of 40 W. Compared to the cardiovascular responses in non-paralyzed subjects, computerized cycle ergometry was found to be associated with higher relative stresses for a given level of absolute work. Mean blood pressure, for example, increased by over 30% during maximal work in individuals with paralysis compared to the typical response obtained for able-bodied subjects. Analysis of the data showed that instead of the 20-30% metabolic efficiency commonly reported for cycle ergometry, the calculated metabolic efficiency during computer-controlled cycle ergometry was only 3.6%.

A group of 37 spinal cord injured (SCI) patients underwent bone density measurements at the distal and proximal end of the tibia by a special computed tomography scanner, the OsteoQuant. Fifteen of these patients had follow-up measurements while enrolled in a lower-limb exercise training program with functional electrical stimulation (FES). The pre-exercise measurements revealed a strong correlation (0.88 < or = r < or = 0.90) of trabecular, subcortical, and cortical bone density between the distal and proximal ends of the tibia. The expected bone density loss during the first two years post injury (as calculated from the regression lines of bone density vs. time post injury) amounted to 51.5% for trabecular, 44.2% for subcortical, and 32.7% for cortical bone. No major bone density loss was calculated after 7 years post injury. Analysis of the bone density data during the FES exercise program revealed various degrees of loss. However, the rate of bone loss for this FES exercise group was less than expected from the regression lines. The reduction of bone loss was between 0.2 and 3.3% per year, and was significant (p < 0.05) for all bone parameters at the distal end and for trabecular bone density at the proximal end of the tibia. These bone density measurements revealed a potentially positive effect of FES exercise intervention for the rehabilitation of SCI patients.

Twelve patients were involved in a 3 month stimulation induced cycling programme at the Royal Perth Rehabilitation Hospital. A number of the patients were less than 1 year post injury, all except one had an incomplete injury, and most were receiving physiotherapy. All patients who completed the programme increased their time of cycling and, in all but one case, the exercise load, indicative of a local training effect. Significant improvements were found in voluntary isometric strength, stimulated isometric strength and stimulated isometric endurance of the quadriceps, muscle grading of the quadriceps and biceps femoris and the cross-sectional areas of the quadriceps and total thigh muscle. No change was found in voluntary isokinetic strength of the quadriceps. All patients with incomplete injuries reported improvements in the activities of daily living (ADL) after the programme. Bone mineral density (BMD) was examined in two patients, one less than 1 year post injury, and one greater than 4 years post injury. The programme of cycling did not restore BMD in the latter patient. However, while the former patient still displayed a reduced BMD after the programme, it is unknown whether this loss of bone was retarded. This needs further investigation. This study demonstrates the effectiveness of a combined physiotherapy/cycling programme in the rehabilitation of people with spinal injuries. To be successful this type of programme has to be incorporated into the rehabilitation process, as has been done at the Sir George Bedbrook Spinal Unit.

To investigate whether exercise training can produce increases in bone mass in spinal cord-injured (SCI) individuals with established disuse osteopenia, nine subjects (age 28.2 years, time since injury 6.0 years, level of injury C5-T7) were recruited for a 9-month training program using functional electrical stimulation cycle ergometry (FES-CE), which produces active muscle contractions in the paralyzed limb. After training, bone mineral density (BMD, by X-ray absorptiometry) increased by 0.047 +/- 0.010 g/cm2 at the lumbar spine; changes in BMD at the femoral neck, distal femur, and proximal tibia were not significant for the group as a whole. In a subset of subjects training at > or = 18 W for at least 3 months (n = 4), BMD increased by 0.095 +/- 0.026 g/cm2 (+18%) at the distal femur. By 6 months of training, a 78% increase in serum osteocalcin was observed, indicating an increase in bone turnover. Urinary calcium and hydroxyproline, indicators of resorptive activity, did not change over the same period. Serum PTH increased 75% over baseline values (from 2.98 +/- 0.15 to 5.22 +/- 0.62 pmol/L) after 6 months’ training, with several individual values in hyperparathyroid range; PTH declined toward baseline values by 9 months. These data establish the feasibility of stimulating site-specific increases in bone mass in severely osteopenic bone with muscle contractions independent of weight-bearing for those subjects able to achieve a threshold power output of 18 W with FES-CE. Calcium supplementation from the outset of training in osteopenic individuals may be advisable to prevent training-induced increases in PTH.

Spinal cord injured (SCI) individuals most often contract their injury at a young age and are deemed to a life of more or less physical inactivity. In addition to the primary implications of the SCI, severe SCI individuals are stigmatized by conditions related to their physically inactive lifestyle. It is unknown if these inactivity related conditions are potentially reversible and the aim of the present study was, therefore, to examine the effect of exercise on SCI individuals. Ten such individuals (six with tetraplegia and four with paraplegia; age 27-45 years; time since injury 3-23 years) were exercise trained for 1 year using an electrically induced computerized feedback controlled cycle ergometer. They trained for up to three times a week (mean 2.3 times), 30 min on each occasion. The gluteal, hamstring and quadriceps muscles were stimulated via electrodes placed on the skin over their motor points. During the first training bouts, a substantial variation in performance was seen between the subjects. A majority of them were capable of performing 30 min of exercise in the first bout; however, two individuals were only able to perform a few minutes of exercise. After training for 1 year all of the subjects were able to perform 30 min of continuous training and the work output had increased from 4 +/- 1 (mean +/- SE) to 17 +/- 2 Kilo Joules per training bout (P < 0.05). The maximal oxygen uptake during electrically induced exercise increased from 1.20 +/- 0.08 litres per minute measured after a few weeks habituation to the exercise to 1.43 +/- 0.09 litres per minute after training for 1 year (P < 0.05). Magnetic resonance cross sectional images of the thigh were performed to estimate muscle mass and an increase of 12% (mean, P < 0.05) was seen in response to 1 year of training. In biopsies taken before exercise various degrees of atrophy were observed in the individual muscle fibres, a phenomenon that was partially normalized in all subjects after training. The fibre type distribution in skeletal muscles is known to shift towards type IIB fibres (fast twitch, fast fatiguable, glycolytic fibres) within the first 2 years after the spinal cord injury. The muscle in the present investigation contained of 63% myosin heavy chain (MHC) isoform IIB, 33% MHC isoform IIA (fast twitch, fatigue resistant) and less than 5% MHC isoform I (slow twitch) before training. A shift towards more fatigue resistant contractile proteins was found after 1 year of training. The percentage of MHC isoform IIA increased to 61% of all contractile protein and a corresponding decrease to 32% was seen in the fast fatiguable MHC isoform IIB, whereas MHC isoform I only comprised 7% of the total amount of MHC. This shift was accompanied by a doubling of the enzymatic activity of citrate synthase, as an indicator of mitochondrial oxidative capacity. It is concluded that inactivity-associated changes in exercise performance capacity and skeletal muscle occurring in SCI individuals after injury are reversible, even up to over 20 years after the injury. It follows that electrically induced exercise training of the paralysed limbs is an effective rehabilitation tool that should be offered to SCI individuals in the future.

OBJECTIVES: To determine if a hybrid exercise (leg plus arm) training program performed immediately after functional electrical stimulation (FES) leg cycle exercise (LCE) training would further improve aerobic capacity when compared with FES leg cycle training alone, and (2) to compare the submaximal responses occurring during both FES-LCE alone and hybrid exercise in the same SCI subjects.

DESIGN: Nonrandomized control trial whereby subjects act as their own control.

SETTING: Outpatient rehabilitation in a primary care hospital.

PATIENTS: A volunteer sample (n = 11) of men 20 to 50 years old with complete spinal cord injury, free from cardiovascular and metabolic disease with spasticity.

INTERVENTIONS: Three phases of exercise training: phase I, progressive FES-LCE to 30 minutes of exercise (n = 11); phase II, 35.2 +/- 16.2 sessions of FES-LCE (n = 11); phase III, 41.4 +/- 17.7 30-minute sessions of hybrid exercise (n = 8).

MAIN OUTCOME MEASURES: Aerobic capacity-a further increase after hybrid exercise when compared with FES-LCE alone; (2) submaximal physiologic parameters (oxygen uptake [VO2], heart rate [HR], blood lactate [BLa-])-measurement of these during constant work rate exercise and a training effect.

RESULTS: VO2 (the body’s ability to utilize oxygen) significantly improved (p < .05) after both FES-LCE and then further after hybrid training. Hybrid exercise training resulted in significantly (p < .05) greater work rates and VO2 values than both FES-LCE at baseline and training work rates.

CONCLUSION: These subjects demonstrated that hybrid exercise performed twice a week provided sufficient intensity to improve aerobic capacity and provide a medium whereby patients with SCI can burn more calories than via FES-LCE alone. This has important implications for improving the health and fitness levels of individuals with SCI and may ultimately reduce their risk of cardiovascular disease.

STUDY DESIGN: Longitudinal training.

OBJECTIVES: To determine the effects of functional electrical stimulated (FES) leg cycle ergometer training on muscle histochemical characteristics in individuals with motor-complete spinal cord injury (SCI).

SETTING: University of Alberta, Edmonton, Alberta, Canada.

METHODS: Six individuals with motor-complete SCI (age 31-50 years; 3-25 years post-injury) trained using FES leg cycle ergometry for 30 min, 3 days per week for 8 weeks. Biopsies of the vastus lateralis muscle were obtained pre- and post-training and analyzed for fibre composition, fibre size and capillarization.

RESULTS: The majority of muscle fibres were classified as type 2 pre- and post-training. Average fibre area increased 23% (P<0.05) and capillary number increased 39% (P<0.05) with training. As a result of these proportional increases, capillarizatio expressed relative to fibre area was unchanged with training.

CONCLUSIONS: FES leg cycle ergometer training results in proportional increases in fibre area and capillary number in individuals with SCI.

OBJECTIVE: To determine the magnitude of changes in muscle mass and lower extremity body composition that could be induced with a regular regimen of functional electrical stimulation (FES)-induced lower-extremity cycling, as well as the distribution of changes in muscle mass among the thigh muscles in persons with spinal cord injury (SCI).

STUDY DESIGN: Thirteen men with neurologically complete motor sensory SCI underwent a 3-phase, FES-induced, ergometry exercise program: phase 1, quadriceps strengthening: phase 2, progressive sequential stimulation to achieve a rhythmic pedaling motion (surface electrodes placed over the quadriceps, hamstrings, and gluteal muscles); phase 3, FES-induced cycling for 30 minutes. Participants moved from one phase to the next when they met the objectives for the current phase.

MEASURES: Computed tomography of legs to assess muscle cross-sectional area and proportion of muscle and adipose tissue. Scans were done at baseline (before subjects started the program), at first follow-up, typically after 65.4+/-5.6 (SD) weekly sessions, and at second follow-up, typically after 98.1+/-9.1 sessions.

RESULTS: Increases in cross-sectional areas were found in the following muscles: rectus femoris (31%, p<.001). sartorius (22%, p<.025), adductor magnus-hamstrings (26%, p<.001), vastus lateralis (39%, p = .001), vastus medialis-intermedius (31%, p = .025). Cross-sectional area of adductor longus and gracilis muscles did not change. The ratio of muscle to adipose tissue increased significantly in thighs and calves. There was no correlation among the total number of exercise sessions and the magnitude of muscle hypertrophy.

CONCLUSIONS: Muscle cross-sectional area and the muscle to adipose tissue ratio of the lower extremities increased during a regular regimen of 2.3 FES-induced lower extremity cycling sessions weekly. The distribution of changes was related to the proximity of muscles to the stimulating electrodes.

OBJECTIVE: To test whether a short period of training leads to adaptations in the cross-sectional area of large conduit arteries and improved blood flow to the paralyzed legs of individuals with spinal cord injury (SCI).

DESIGN: Before-after trial.

SETTING: Rehabilitation center, academic medical center.

PARTICIPANTS: Nine men with spinal cord lesions.

INTERVENTION: Six weeks of cycling using a functional electrically stimulated leg cycle ergometer (FES-LCE).

MAIN OUTCOME MEASURES: Longitudinal images and simultaneous velocity spectra were measured in the common carotid (CA) and femoral (FA) arteries using quantitative duplex Doppler ultrasound examination. Arterial diameters, peak systolic inflow volumes (PSIVs), mean inflow volumes (MIVs), and a velocity index (VI), representing the peripheral resistance, were obtained at rest. PSIVs and VI were obtained during 3 minutes of hyperemia following 20 minutes of FA occlusion.

RESULTS: Training resulted in significant increases in diameter (p < .01), PSIVs (p < .01), and MIVs (p < .05), and reduced VI (p < .01) of the FA, whereas values in the CA remained unchanged. Postocclusive hyperemic responses were augmented, indicated by significantly higher PSIVs (p <.01) and a trend toward lower VI.

CONCLUSION: Six weeks of FES-LCE training increased the cross-sectional area of large conduit arteries and improved blood flow to the paralyzed legs of individuals with SCI.

The purpose of the present study was to determine the effect of a spinal cord injury (SCI) on resting vascular resistance in paralyzed legs in humans. To accomplish this goal, we measured blood pressure and resting flow above and below the lesion (by using venous occlusion plethysmography) in 11 patients with SCI and in 10 healthy controls (C). Relative vascular resistance was calculated as mean arterial pressure in millimeters of mercury divided by the arterial blood flow in milliliters per minute per 100 milliliters of tissue. Arterial blood flow in the sympathetically deprived and paralyzed legs of SCI was significantly lower than leg blood flow in C. Because mean arterial pressure showed no differences between both groups, leg vascular resistance in SCI was significantly higher than in C. Within the SCI group, arterial blood flow was significantly higher and vascular resistance significantly lower in the arms than in the legs. To distinguish between the effect of loss of central neural control vs. deconditioning, a group of nine SCI patients was trained for 6 wk and showed a 30% increase in leg blood flow with unchanged blood pressure levels, indicating a marked reduction in vascular resistance. In conclusion, vascular resistance is increased in the paralyzed legs of individuals with SCI and is reversible by training.

DESIGN: Longitudinal training.

OBJECTIVES: The purpose was to determine the effect of electrical stimulation (ES)-assisted cycling (30 min/day, 3 days/week for 8 weeks) on glucose tolerance and insulin sensitivity in people with spinal cord injury (SCI).

SETTING: The Steadward Centre, Alberta, Canada.

METHODS: Seven participants with motor complete SCI (five males and two females aged 30 to 53 years, injured 3-40 years, C5-T10) underwent 2-h oral glucose tolerance tests (OGTT, n=7) and hyperglycaemic clamp tests (n=3) before and after 8 weeks of training with ES-assisted cycling.

RESULTS: Results indicated that subjects’ glucose level were significantly lower at 2 h OGTT following 8 weeks of training (122.4+/-10 vs 139.9+/-16, P=0.014). Two-hour hyperglycaemic clamps tests showed improvement in all three people for glucose utilisation and in two of three people for insulin sensitivity.

CONCLUSIONS: These results suggested that exercise with ES-assisted cycling is beneficial for the prevention and treatment of Type 2 diabetes mellitus in people with SCI.

The effect of functional electrical stimulation (FES) training on body composition, assessed by computed tomography, and the effect of spasticity, assessed by both objective and subjective measures, are evaluated. Fifteen motor-complete spinal-cord-injured men participated in the study. Eight of the 15 subjects undertook FES cycling 3 times weekly for 6 months. Whole body computed tomography scans evaluated changes in body composition. Simultaneous Modified Ashworth Scale and electromyography (EMG) measurements, resistive torque (Kin-Com) and EMG measurements, and self-ratings with Visual Analogue Scale during four consecutive days were used to evaluate changes in spasticity. Lower extremity muscle volume increased by an average of 1300 cm3 (p < 0.001) in the training group compared to the control group, who experienced no change. Otherwise no changes in body composition were seen. Significant correlations (Spearman) were found between individual EMG activity recordings and movement-provoked Modified Ashworth Scale ratings in 26% of the test situations, irrespective of group and time. The objective and subjective evaluation of movement-provoked passive (viscoelastic) and active (spasticity-related) resistance remained unchanged.

The effect of early intervention using functional electric stimulation cycle ergometry (FES-CE) on skeletal muscle morphology was evaluated in traumatic spinal cord injured (SCI) patients 4 – 6 weeks after injury. Motor complete SCI patients (n = 10) were assigned to either a SCI control group (IC) or FES-CE group (IE) and compared to uninjured controls (UIC) matched for age, activity, and gender. Training via FES-CE was performed 3 days/week for 13 weeks. In the FES-CE trained group, power output increased from 2.4 ± 88 Watts to 24.5 ± 3.2 Watts. Muscle biopsies were taken from the vastus lateralis muscle at pre- and posttraining for subsequent morphological analysis. Without intervention, muscle fiber cross sectional area (CSAf ) decreased 38% and 65% at 6 and 19 weeks post-SCI, respectively. The loss of CSAf had no impact on myonuclear density. Following 13 weeks of FES-CE training, CSAf increased was 63% greater when compared to the IC group. Results of the present investigation suggest that the initiation of FES-CE in first weeks after traumatic SCI attenuates the loss of muscle mass and power output.

OBJECTIVE: To assess the time course of arterial adaptations during 6 weeks of functional electric stimulation (FES) training and 6 weeks of detraining in subjects with spinal cord injury (SCI).

DESIGN: Intervention study (before-after trial). SETTING: University medical center.

PARTICIPANTS: Volunteer sample of 9 subjects with SCI.

INTERVENTIONS: Six weeks of twice weekly FES cycling and 6 weeks of detraining.

MAIN OUTCOME MEASURES: Vascular characteristics were measured by plethysmography (baseline and peak blood flow of the thigh) and echo Doppler (diameter of the femoral artery and flow-mediated dilation [FMD]).

RESULTS: After 2 weeks of FES training, arterial characteristics changed significantly; there was an increase in baseline and peak blood flow, an increase in femoral artery diameter, and a decrease in FMD of the femoral artery. Detraining reversed baseline and peak thigh blood flow, vascular resistance, and femoral diameter toward pretraining values within 1 week. However, detraining did not restore the FMD of the femoral artery, even after 6 weeks.

CONCLUSIONS: Two weeks of hybrid FES training (4 exercise bouts) is sufficient to improve peak leg blood flow and arterial diameter, and to normalize FMD. In addition, detraining results in rapidly reversed vascular characteristics within 1 week.

Inactivity and muscular adaptations following spinal cord injury (SCI) result in secondary complications such as cardiovascular disease, obesity, and pressure sores. Functional electrically stimulated (FES) cycling can potentially reduce these complications, but previous studies have provided inconsistent results. We studied the effect of intensive long-term FES cycle training on muscle properties in 11 SCI subjects (mean +/- SEM: 41.8 +/- 2.3 years) who had trained for up to 1 hour/day, 5 days/week, for 1 year. Comparative measurements were made in 10 able-bodied (AB) subjects. Quadriceps maximal electrically stimulated torque increased fivefold (n = 5), but remained lower than in AB individuals. Relative force response at 1 HZ decreased, relaxation rate remained unchanged, and fatigue resistance improved significantly. Power output (PO) improved to a lesser extent than quadriceps torque and not to a greater extent than has been reported previously. We need to understand the factors that limit PO in order to maximize the benefits of FES cycling.

Spinal cord injury (SCI) leads to severe bone loss in the paralysed limbs and to a resulting increased fracture risk thereof. Since long bone fractures can lead to comorbidities and a reduction in quality of life, it is important to improve bone strength in people with chronic SCI. In this prospective longitudinal cohort study, we investigated whether functional electrical stimulation (FES) induced high-volume cycle training can partially reverse the loss of bone substance in the legs after chronic complete SCI. Eleven participants with motor-sensory complete SCI (mean age 41.9+/-7.5 years; 11.0+/-7.1 years post injury) were recruited. After an initial phase of 14+/-7 weeks of FES muscle conditioning, participants performed on average 3.7+/-0.6 FES-cycling sessions per week, of 58+/-5 min each, over 12 months at each individual’s highest power output. Bone and muscle parameters were investigated in the legs by means of peripheral quantitative computed tomography before the muscle conditioning (t1), and after six (t2) and 12 months (t3) of high-volume FES-cycle training. After 12 months of FES-cycling, trabecular and total bone mineral density (BMD) as well as total cross-sectional area in the distal femoral epiphysis increased significantly by 14.4+/-21.1%, 7.0+/-10.8% and 1.2+/-1.5%, respectively. Bone parameters in the femoral shaft showed small but significant decreases, with a reduction of 0.4+/-0.4% in cortical BMD, 1.8+/-3.0% in bone mineral content, and 1.5+/-2.1% in cortical thickness. These decreases mainly occurred between t1 and t2. No significant changes were found in any of the measured bone parameters in the tibia. Muscle CSA at the thigh increased significantly by 35.5+/-18.3%, while fat CSA at the shank decreased by 16.7+/-12.3%. Our results indicate that high-volume FES-cycle training leads to site-specific skeletal changes in the paralysed limbs, with an increase in bone parameters at the actively loaded distal femur but not the passively loaded tibia. Thus, we conclude that high-volume FES-induced cycle training has clinical relevance as it can partially reverse bone loss and thus may reduce fracture risk at this fracture prone site.

Persons with spinal cord injury (SCI) are at a heightened risk of developing type II diabetes and cardiovascular disease. The purpose of this investigation was to conduct an analysis of metabolic, body composition, and neurological factors before and after 10 weeks of functional electrical stimulation (FES) cycling in persons with SCI. Eighteen individuals with SCI received FES cycling 2-3 times per week for 10 weeks. Body composition was analyzed by dual X-ray absorptiometry. The American Spinal Injury Association (ASIA) neurological classification of SCI test battery was used to assess motor and sensory function. An oral glucose tolerance (OGTT) and insulin-response test was performed to assess blood glucose control. Additional metabolic variables including plasma cholesterol (total-C, HDL-C, LDL-C), triglyceride, and inflammatory markers (IL-6, TNF-alpha, and CRP) were also measured. Total FES cycling power and work done increased with training. Lean muscle mass also increased, whereas, bone and adipose mass did not change. The ASIA motor and sensory scores for the lower extremity significantly increased with training. Blood glucose and insulin levels were lower following the OGTT after 10 weeks of training. Triglyceride levels did not change following training. However, levels of IL-6, TNF-alpha, and CRP were all significantly reduced.

Functional electrical stimulation (FES) cycling ergometer has been utilized in recent decades for rehabilitation by sequentially stimulating the large leg-actuating muscles of paralyzed leg muscles to produce cyclical leg motion. A number of studies reported physiological adaptations after regular FES-cycling exercise (FESCE) training in subjects with spinal cord injury, stroke, cerebral palsy and other conditions. This article provides a comprehensive overview of general aspects of FES cycling systems and clinical applications of FESCE. The studies cited in this article provide supportive findings for the potential clinical efficacy of FESCE for reducing the risk of secondary medical complications in subjects with paralysis. The potential therapeutic benefits of FESCE include conditioning the cardiopulmonary, muscular, and skeletal systems, and improving other physiological and psychological performances. Our recent pilot study also indicated that the decrease of leg spasticity in subjects with cerebral palsy is one of the acute effects of FESCE. In conclusion, we recommend that FESCE is of benefit in a variety of aspects to improve the general condition and to prevent deterioration in subjects with central neurological impairments.

OBJECTIVE: To investigate the long-term effects of functional electrical stimulation (FES)-evoked cycle training cadence on leg muscle hypertrophy and electrically evoked strength.

DESIGN: Open intervention study.

SETTING: Laboratory setting.

PARTICIPANTS: Untrained individuals with chronic spinal cord injury (N=8).

INTERVENTIONS: Six weeks (3d/wk) of training on an isokinetic FES cycle ergometer. For each subject, 1 leg was randomly allocated to cycling at 10 revolutions per minute (rpm) (LOW) for 30min/d, and the other cycling at 50rpm (HIGH) for 30min/d.

MAIN OUTCOME MEASURES: Pre- and posttraining measurements of lower limb circumference were performed at the distal and middle position of each thigh. Electrically evoked quadriceps muscle torque during an isometric contraction was also assessed.

RESULTS: Six weeks of FES cycle training significantly increased thigh girth in both LOW and HIGH groups. At midthigh, girth increases induced by LOW (6.6%±1.2%) were significantly greater than those by HIGH (3.6%±0.8%). LOW also produced greater gains in electrically evoked isometric torque than HIGH after training.

CONCLUSIONS: These results suggest that lower pedaling cadences evoke greater muscle hypertrophy and electrically stimulated muscle strength compared with higher cadences.

FES leg cycling exercise is a physical activity that has potential to provide aerobic fitness and cardiovascular health benefits for individuals with SCI. However, there are few high-quality studies or systematic reviews for sufficient Level I or Level II evidence supporting the putative benefits of FES-evoked exercise after SCI, to make sound determination of its clinical efficacy to reduce obesity diabetes and cardiovascular disease. This paper samples some of the recent evidence supporting FES lower-limb exercise, by itself, and makes recommendations about how “critical dose-potency” might be achieved to provide clinical and health benefits from FES-exercise.

The authors of this prospective, single-case study evaluated the potential for functional recovery from chronic spinal cord injury (SCI). The patient was motor complete with minimal and transient sensory perception in the left hemibody. His condition was classified as C-2 American Spinal Injury Association (ASIA) Grade A and he had experienced no substantial recovery in the first 5 years after traumatic SCI. Clinical experience and evidence from the scientific literature suggest that further recovery would not take place. When the study began in 1999, the patient was tetraplegic and unable to breathe without assisted ventilation; his condition classification persisted as C-2 ASIA Grade A. Magnetic resonance imaging revealed severe injury at the C-2 level that had left a central fluid-filled cyst surrounded by a narrow donutlike rim of white matter. Five years after the injury a program known as “activity-based recovery” was instituted. The hypothesis was that patterned neural activity might stimulate the central nervous system to become more functional, as it does during development. Over a 3-year period (5-8 years after injury), the patient’s condition improved from ASIA Grade A to ASIA Grade C, an improvement of two ASIA grades. Motor scores improved from 0/100 to 20/100, and sensory scores rose from 5-7/112 to 58-77/112. Using electromyography, the authors documented voluntary control over important muscle groups, including the right hemidiaphragm (C3-5), extensor carpi radialis (C-6), and vastus medialis (L2-4). Reversal of osteoporosis and an increase in muscle mass was associated with this recovery. Moreover, spasticity decreased, the incidence of medical complications fell dramatically, and the incidence of infections and use of antibiotic medications was reduced by over 90%. These improvements occurred despite the fact that less than 25 mm2 of tissue (approximately 25%) of the outer cord (presumably white matter) had survived at the injury level. The primary novelty of this report is the demonstration that substantial recovery of function (two ASIA grades) is possible in a patient with severe C-2 ASIA Grade A injury, long after the initial SCI. Less severely injured (lower injury level, clinically incomplete lesions) individuals might achieve even more meaningful recovery. The role of patterned neural activity in regeneration and recovery of function after SCI therefore appears a fruitful area for future investigation.

Two years of functional electrical stimulation cycling (FESC) as a researcher and subject have given me an insight into the direction that future FESC should take as well as providing me with significant health benefits and an enjoyable and functional ability to cycle. If FESC is to benefit spinal cord injured persons (SCIPs), researchers must turn their attention to making the activity convenient and enjoyable. What follows is a personal view and will be less scientifically rigorous than other presentations but hopefully still of value. It calls upon my experience as a general medical practitioner with a special interest in the value of exercise, a human powered vehicle enthusiast, an amateur FES researcher, but most importantly, an SCIP and FES cyclist.

Functional electrical stimulation (FES) cycling ergometer has been utilized in recent decades for rehabilitation by sequentially stimulating the large leg-actuating muscles of paralyzed leg muscles to produce cyclical leg motion. A number of studies reported physiological adaptations after regular FES-cycling exercise (FESCE) training in subjects with spinal cord injury, stroke, cerebral palsy and other conditions. This article provides a comprehensive overview of general aspects of FES cycling systems and clinical applications of FESCE. The studies cited in this article provide supportive findings for the potential clinical efficacy of FESCE for reducing the risk of secondary medical complications in subjects with paralysis. The potential therapeutic benefits of FESCE include conditioning the cardiopulmonary, muscular, and skeletal systems, and improving other physiological and psychological performances. Our recent pilot study also indicated that the decrease of leg spasticity in subjects with cerebral palsy is one of the acute effects of FESCE. In conclusion, we recommend that FESCE is of benefit in a variety of aspects to improve the general condition and to prevent deterioration in subjects with central neurological impairments.

A low cost clinical exercise system was developed for the spinal cord injured, based on a bicycle ergometer and electrical stimulation. A pilot project was conducted, using the system, to examine the effects of stimulation induced cycling in long term paraplegics. The project comprised 2 phases of exercise, a strengthening phase involving a 12 week programme of electrical stimulation to the quadriceps and hamstrings and a 12 week cycling phase. Physiological, morphological and biochemical parameters were measured for each subject, at the beginning of the programme and following each phase. Results showed that a programme of stimulation induced lower limb exercise increased the exercise tolerance of all patients, as determined by a progressive increase in exercise time, cycling rate and exercise load. The enhanced exercise tolerance was a result of increases in local muscle strength and endurance. Increases in thigh muscle area and joint range of motion were recorded and all incomplete subjects reported an improvement in functional capabilities and general wellbeing.

Twelve patients were involved in a 3 month stimulation induced cycling programme at the Royal Perth Rehabilitation Hospital. A number of the patients were less than 1 year post injury, all except one had an incomplete injury, and most were receiving physiotherapy. All patients who completed the programme increased their time of cycling and, in all but one case, the exercise load, indicative of a local training effect. Significant improvements were found in voluntary isometric strength, stimulated isometric strength and stimulated isometric endurance of the quadriceps, muscle grading of the quadriceps and biceps femoris and the cross-sectional areas of the quadriceps and total thigh muscle. No change was found in voluntary isokinetic strength of the quadriceps. All patients with incomplete injuries reported improvements in the activities of daily living (ADL) after the programme. Bone mineral density (BMD) was examined in two patients, one less than 1 year post injury, and one greater than 4 years post injury. The programme of cycling did not restore BMD in the latter patient. However, while the former patient still displayed a reduced BMD after the programme, it is unknown whether this loss of bone was retarded. This needs further investigation. This study demonstrates the effectiveness of a combined physiotherapy/cycling programme in the rehabilitation of people with spinal injuries. To be successful this type of programme has to be incorporated into the rehabilitation process, as has been done at the Sir George Bedbrook Spinal Unit.

The authors of this prospective, single-case study evaluated the potential for functional recovery from chronic spinal cord injury (SCI). The patient was motor complete with minimal and transient sensory perception in the left hemibody. His condition was classified as C-2 American Spinal Injury Association (ASIA) Grade A and he had experienced no substantial recovery in the first 5 years after traumatic SCI. Clinical experience and evidence from the scientific literature suggest that further recovery would not take place. When the study began in 1999, the patient was tetraplegic and unable to breathe without assisted ventilation; his condition classification persisted as C-2 ASIA Grade A. Magnetic resonance imaging revealed severe injury at the C-2 level that had left a central fluid-filled cyst surrounded by a narrow donutlike rim of white matter. Five years after the injury a program known as “activity-based recovery” was instituted. The hypothesis was that patterned neural activity might stimulate the central nervous system to become more functional, as it does during development. Over a 3-year period (5-8 years after injury), the patient’s condition improved from ASIA Grade A to ASIA Grade C, an improvement of two ASIA grades. Motor scores improved from 0/100 to 20/100, and sensory scores rose from 5-7/112 to 58-77/112. Using electromyography, the authors documented voluntary control over important muscle groups, including the right hemidiaphragm (C3-5), extensor carpi radialis (C-6), and vastus medialis (L2-4). Reversal of osteoporosis and an increase in muscle mass was associated with this recovery. Moreover, spasticity decreased, the incidence of medical complications fell dramatically, and the incidence of infections and use of antibiotic medications was reduced by over 90%. These improvements occurred despite the fact that less than 25 mm2 of tissue (approximately 25%) of the outer cord (presumably white matter) had survived at the injury level. The primary novelty of this report is the demonstration that substantial recovery of function (two ASIA grades) is possible in a patient with severe C-2 ASIA Grade A injury, long after the initial SCI. Less severely injured (lower injury level, clinically incomplete lesions) individuals might achieve even more meaningful recovery. The role of patterned neural activity in regeneration and recovery of function after SCI therefore appears a fruitful area for future investigation.

Two years of functional electrical stimulation cycling (FESC) as a researcher and subject have given me an insight into the direction that future FESC should take as well as providing me with significant health benefits and an enjoyable and functional ability to cycle. If FESC is to benefit spinal cord injured persons (SCIPs), researchers must turn their attention to making the activity convenient and enjoyable. What follows is a personal view and will be less scientifically rigorous than other presentations but hopefully still of value. It calls upon my experience as a general medical practitioner with a special interest in the value of exercise, a human powered vehicle enthusiast, an amateur FES researcher, but most importantly, an SCIP and FES cyclist.

Functional electrical stimulation (FES)-induced leg exercise offers the potential for individuals with lower-limb paralysis to otherwise gain some benefits conferred by leg exercise. Although its original intent is to reactivate the leg muscles to produce functional upright mobility, as a rehabilitation therapy, FES-evoked exercise increases the whole-body metabolism of individuals with spinal cord injury (SCI) so that they may gain general and localized health and fitness benefits. The physiological and psychosocial responses during FES-evoked cycling, standing, rowing, leg extension, or stepping have been extensively explored for over 20 years. Some of the advantages of such exercise include augmented cardiorespiratory fitness, promotion of leg blood circulation, increased activity of specific metabolic enzymes or hormones, greater muscle volume and fiber size, enhanced functional exercise capacity such as strength and endurance, and altered bone mineral density. Positive psychosocial adaptations have also been reported among SCI individuals who undergo FES exercise. This article presents a position review of the available literature on the effects of FES-evoked exercise since the earliest date until 2007, to warrant a conclusion about the current status and potential of FES-evoked exercise for paralyzed people.

Functional electrical stimulation (FES) cycling ergometer has been utilized in recent decades for rehabilitation by sequentially stimulating the large leg-actuating muscles of paralyzed leg muscles to produce cyclical leg motion. A number of studies reported physiological adaptations after regular FES-cycling exercise (FESCE) training in subjects with spinal cord injury, stroke, cerebral palsy and other conditions. This article provides a comprehensive overview of general aspects of FES cycling systems and clinical applications of FESCE. The studies cited in this article provide supportive findings for the potential clinical efficacy of FESCE for reducing the risk of secondary medical complications in subjects with paralysis. The potential therapeutic benefits of FESCE include conditioning the cardiopulmonary, muscular, and skeletal systems, and improving other physiological and psychological performances. Our recent pilot study also indicated that the decrease of leg spasticity in subjects with cerebral palsy is one of the acute effects of FESCE. In conclusion, we recommend that FESCE is of benefit in a variety of aspects to improve the general condition and to prevent deterioration in subjects with central neurological impairments.

A low cost clinical exercise system was developed for the spinal cord injured, based on a bicycle ergometer and electrical stimulation. A pilot project was conducted, using the system, to examine the effects of stimulation induced cycling in long term paraplegics. The project comprised 2 phases of exercise, a strengthening phase involving a 12 week programme of electrical stimulation to the quadriceps and hamstrings and a 12 week cycling phase. Physiological, morphological and biochemical parameters were measured for each subject, at the beginning of the programme and following each phase. Results showed that a programme of stimulation induced lower limb exercise increased the exercise tolerance of all patients, as determined by a progressive increase in exercise time, cycling rate and exercise load. The enhanced exercise tolerance was a result of increases in local muscle strength and endurance. Increases in thigh muscle area and joint range of motion were recorded and all incomplete subjects reported an improvement in functional capabilities and general wellbeing..

Twelve patients were involved in a 3 month stimulation induced cycling programme at the Royal Perth Rehabilitation Hospital. A number of the patients were less than 1 year post injury, all except one had an incomplete injury, and most were receiving physiotherapy. All patients who completed the programme increased their time of cycling and, in all but one case, the exercise load, indicative of a local training effect. Significant improvements were found in voluntary isometric strength, stimulated isometric strength and stimulated isometric endurance of the quadriceps, muscle grading of the quadriceps and biceps femoris and the cross-sectional areas of the quadriceps and total thigh muscle. No change was found in voluntary isokinetic strength of the quadriceps. All patients with incomplete injuries reported improvements in the activities of daily living (ADL) after the programme. Bone mineral density (BMD) was examined in two patients, one less than 1 year post injury, and one greater than 4 years post injury. The programme of cycling did not restore BMD in the latter patient. However, while the former patient still displayed a reduced BMD after the programme, it is unknown whether this loss of bone was retarded. This needs further investigation. This study demonstrates the effectiveness of a combined physiotherapy/cycling programme in the rehabilitation of people with spinal injuries. To be successful this type of programme has to be incorporated into the rehabilitation process, as has been done at the Sir George Bedbrook Spinal Unit

Two years of functional electrical stimulation cycling (FESC) as a researcher and subject have given me an insight into the direction that future FESC should take as well as providing me with significant health benefits and an enjoyable and functional ability to cycle. If FESC is to benefit spinal cord injured persons (SCIPs), researchers must turn their attention to making the activity convenient and enjoyable. What follows is a personal view and will be less scientifically rigorous than other presentations but hopefully still of value. It calls upon my experience as a general medical practitioner with a special interest in the value of exercise, a human powered vehicle enthusiast, an amateur FES researcher, but most importantly, an SCIP and FES cyclist..

Functional electrical stimulation (FES) cycling ergometer has been utilized in recent decades for rehabilitation by sequentially stimulating the large leg-actuating muscles of paralyzed leg muscles to produce cyclical leg motion. A number of studies reported physiological adaptations after regular FES-cycling exercise (FESCE) training in subjects with spinal cord injury, stroke, cerebral palsy and other conditions. This article provides a comprehensive overview of general aspects of FES cycling systems and clinical applications of FESCE. The studies cited in this article provide supportive findings for the potential clinical efficacy of FESCE for reducing the risk of secondary medical complications in subjects with paralysis. The potential therapeutic benefits of FESCE include conditioning the cardiopulmonary, muscular, and skeletal systems, and improving other physiological and psychological performances. Our recent pilot study also indicated that the decrease of leg spasticity in subjects with cerebral palsy is one of the acute effects of FESCE. In conclusion, we recommend that FESCE is of benefit in a variety of aspects to improve the general condition and to prevent deterioration in subjects with central neurological impairments.

OBJECTIVE: To examine the effect of long-term lower extremity functional electrical stimulation (FES) cycling on the physical integrity and functional recovery in people with chronic spinal cord injury (SCI).

DESIGN: Retrospective cohort, mean follow-up 29.1 months, and cross-sectional evaluation.

SETTING: Washington University Spinal Cord Injury Neurorehabilitation Center, referral center.

PARTICIPANTS: Twenty-five people with chronic SCI who received FES during cycling were matched by age, gender, injury level, and severity, and duration of injury to 20 people with SCI who received range of motion and stretching.

INTERVENTION: Lower extremity FES during cycling as part of an activity-based restorative treatment regimen.

MAIN OUTCOME MEASURE: Change in neurological function: motor, sensory, and combined motor-sensory scores (CMSS) assessed by the American Spinal Injury Association Impairment scale. Response was defined as ≥ 1 point improvement.

RESULTS: FES was associated with an 80% CMSS responder rate compared to 40% in controls. An average 9.6 CMSS point loss among controls was offset by an average 20-point gain among FES subjects. Quadriceps muscle mass was on average 36% higher and intra/inter-muscular fat 44% lower, in the FES group. Hamstring and quadriceps muscle strength was 30 and 35% greater, respectively, in the FES group. Quality of life and daily function measures were significantly higher in FES group.

CONCLUSION: FES during cycling in chronic SCI may provide substantial physical integrity benefits, including enhanced neurological and functional performance, increased muscle size and force-generation potential, reduced spasticity, and improved quality of life.

The aim of this study was to determine the efficacy and the effects of functional electrical stimulated cycling (FES cycling) in patients with spinal cord injury during their rehabilitation in a special acute care unit. Thirty patients [10 with American Spinal Injury Association Impairment Scale (AIS) grade A, three with AIS grade B, 15 with AIS grade C, two with AIS grade D] aged 44±15.5 years and 2 (median) (interquartile range, 1.0-4.25) months after spinal cord injury were included in the study. The patients participated in a 20-min FES-cycling program 2 days per week for 4 weeks during their acute inpatient rehabilitation. The influence on muscle cross-section, muscle and leg circumference, spasticity, and the walking ability parameter (distance, time, aids) was measured. Muscle stimulation intensity and output parameters (pedalling time and distance) were also recorded. Spasticity decreased during hip abduction and adduction (70 and 98.1%, respectively). Spasticity during knee flexion and knee extension decreased by 66.8 and 76.6%, and a decrease was found during dorsal foot extension (67.8%; for all, P<0.05). Presession-postsession comparisons showed that after 4 weeks of FES cycling, an increase in the circumference of the cross-sectional area of 15.3% on the left and of 17% on the right m. rectus femoris could be observed in group AIS A+B. In the AIS C+D group, the circumference of the left m. rectus femoris increased by 25% and that of the right m. rectus femoris by 21% (for all, P<0.05). The results of the study show that FES cycling in combination with function-oriented physiotherapy and occupational therapy can have a positive influence on spasticity, walking ability, and muscular reactivation. It seems to support circulatory processes within the rehabilitation of paraplegics already after a 4-week intervention.

STUDY DESIGN: Prospective single-arm study.

OBJECTIVES: To investigate the effect of functional electrical stimulation (FES) cycling on late functional recovery, spasticity, gait parameters and oxygen consumption during walking in patients with chronic incomplete spinal cord injury (SCI).

SETTING: Turkish Armed Forces Rehabilitation Center, Ankara, Turkey.

METHODS: Ten patients with chronic (duration of more than 2 years) incomplete SCI who could ambulate at least 10 m independently or with the assistance of a cane or walker, but no hip-knee-ankle-foot orthosis. The subjects underwent 1-h FES cycling sessions three times a week for 16 weeks. Outcome measures including the total motor score, the Functional Independence Measure (FIM) score, the Modified Ashworth Scale for knee spasticity, temporal spatial gait parameters and oxygen consumption rate during walking were assessed at baseline, 3 and 6 months after the baseline.

RESULTS: There were statistically significant improvements in total motor scores, the FIM scores and spasticity level at the 6-month follow-up (P<0.01). The changes in gait parameters reached no significant level (P>0.05). Oxygen consumption rate of the patients showed significant reduction at only 6 months compared with baseline (P<0.01).

CONCLUSION: The results suggest that FES cycling may provide some functional improvements in the late period of SCI.

A group of 37 spinal cord injured (SCI) patients underwent bone density measurements at the distal and proximal end of the tibia by a special computed tomography scanner, the OsteoQuant. Fifteen of these patients had follow-up measurements while enrolled in a lower-limb exercise training program with functional electrical stimulation (FES). The pre-exercise measurements revealed a strong correlation (0.88 < or = r < or = 0.90) of trabecular, subcortical, and cortical bone density between the distal and proximal ends of the tibia. The expected bone density loss during the first two years post injury (as calculated from the regression lines of bone density vs. time post injury) amounted to 51.5% for trabecular, 44.2% for subcortical, and 32.7% for cortical bone. No major bone density loss was calculated after 7 years post injury. Analysis of the bone density data during the FES exercise program revealed various degrees of loss. However, the rate of bone loss for this FES exercise group was less than expected from the regression lines. The reduction of bone loss was between 0.2 and 3.3% per year, and was significant (p < 0.05) for all bone parameters at the distal end and for trabecular bone density at the proximal end of the tibia. These bone density measurements revealed a potentially positive effect of FES exercise intervention for the rehabilitation of SCI patients.

To investigate whether exercise training can produce increases in bone mass in spinal cord-injured (SCI) individuals with established disuse osteopenia, nine subjects (age 28.2 years, time since injury 6.0 years, level of injury C5-T7) were recruited for a 9-month training program using functional electrical stimulation cycle ergometry (FES-CE), which produces active muscle contractions in the paralyzed limb. After training, bone mineral density (BMD, by X-ray absorptiometry) increased by 0.047 +/- 0.010 g/cm2 at the lumbar spine; changes in BMD at the femoral neck, distal femur, and proximal tibia were not significant for the group as a whole. In a subset of subjects training at > or = 18 W for at least 3 months (n = 4), BMD increased by 0.095 +/- 0.026 g/cm2 (+18%) at the distal femur. By 6 months of training, a 78% increase in serum osteocalcin was observed, indicating an increase in bone turnover. Urinary calcium and hydroxyproline, indicators of resorptive activity, did not change over the same period. Serum PTH increased 75% over baseline values (from 2.98 +/- 0.15 to 5.22 +/- 0.62 pmol/L) after 6 months’ training, with several individual values in hyperparathyroid range; PTH declined toward baseline values by 9 months. These data establish the feasibility of stimulating site-specific increases in bone mass in severely osteopenic bone with muscle contractions independent of weight-bearing for those subjects able to achieve a threshold power output of 18 W with FES-CE. Calcium supplementation from the outset of training in osteopenic individuals may be advisable to prevent training-induced increases in PTH.

Spinal cord injured (SCI) individuals have a substantial loss of bone mass in the lower limbs, equaling approximately 50% of normal values in the proximal tibia, and this has been associated with a high incidence of low impact fractures. To evaluate if this inactivity-associated condition in the SCI population can be reversed with prolonged physical training, ten SCI individuals [ages 35.3 +/- 2.3 years (mean +/- standard error [SE]); post injury time: 12.5 +/- 2.7 years, range 2-24 years; level of lesion: C6-Th4; weight: 78 +/- 3.8 kg] performed 12 months of Functional Electrical Stimulated (FES) upright cycling for 30 min per day, 3 days per week, followed by six months with only one weekly training session. Bone mineral density (BMD) was determined before training and 12 and 18 months later. BMD was measured in the lumbar spine, the femoral neck, and the proximal tibia by dual energy absorptiometry (DEXA, Nordland XR 26 MK1). Before training, BMD was in the proximal tibia (52%), as well as in the femoral neck, lower in SCI subjects than in controls of same age (P < 0.05). BMD of the lumbar spine did not differ between groups (P > 0.05). After 12 months of training, the BMD of the proximal tibia had increased 10%, from 0.49 +/- 0.04 to 0. 54 +/- 0.04 g/cm2 (P < 0.05). After a further 6 months with reduced training, the BMD in the proximal tibia no longer differed from the BMD before training (P > 0.05). No changes were observed in the lumbar spine or in the femoral neck in response to FES cycle training. It is concluded that in SCI, the loss of bone mass in the proximal tibia can be partially reversed by regular long-term FES cycle exercise. However, one exercise session per week is insufficient to maintain this increase.

The authors of this prospective, single-case study evaluated the potential for functional recovery from chronic spinal cord injury (SCI). The patient was motor complete with minimal and transient sensory perception in the left hemibody. His condition was classified as C-2 American Spinal Injury Association (ASIA) Grade A and he had experienced no substantial recovery in the first 5 years after traumatic SCI. Clinical experience and evidence from the scientific literature suggest that further recovery would not take place. When the study began in 1999, the patient was tetraplegic and unable to breathe without assisted ventilation; his condition classification persisted as C-2 ASIA Grade A. Magnetic resonance imaging revealed severe injury at the C-2 level that had left a central fluid-filled cyst surrounded by a narrow donutlike rim of white matter. Five years after the injury a program known as “activity-based recovery” was instituted. The hypothesis was that patterned neural activity might stimulate the central nervous system to become more functional, as it does during development. Over a 3-year period (5-8 years after injury), the patient’s condition improved from ASIA Grade A to ASIA Grade C, an improvement of two ASIA grades. Motor scores improved from 0/100 to 20/100, and sensory scores rose from 5-7/112 to 58-77/112. Using electromyography, the authors documented voluntary control over important muscle groups, including the right hemidiaphragm (C3-5), extensor carpi radialis (C-6), and vastus medialis (L2-4). Reversal of osteoporosis and an increase in muscle mass was associated with this recovery. Moreover, spasticity decreased, the incidence of medical complications fell dramatically, and the incidence of infections and use of antibiotic medications was reduced by over 90%. These improvements occurred despite the fact that less than 25 mm2 of tissue (approximately 25%) of the outer cord (presumably white matter) had survived at the injury level. The primary novelty of this report is the demonstration that substantial recovery of function (two ASIA grades) is possible in a patient with severe C-2 ASIA Grade A injury, long after the initial SCI. Less severely injured (lower injury level, clinically incomplete lesions) individuals might achieve even more meaningful recovery. The role of patterned neural activity in regeneration and recovery of function after SCI therefore appears a fruitful area for future investigation.

Two years of functional electrical stimulation cycling (FESC) as a researcher and subject have given me an insight into the direction that future FESC should take as well as providing me with significant health benefits and an enjoyable and functional ability to cycle. If FESC is to benefit spinal cord injured persons (SCIPs), researchers must turn their attention to making the activity convenient and enjoyable. What follows is a personal view and will be less scientifically rigorous than other presentations but hopefully still of value. It calls upon my experience as a general medical practitioner with a special interest in the value of exercise, a human powered vehicle enthusiast, an amateur FES researcher, but most importantly, an SCIP and FES cyclist..

Spinal cord injured (SCI) individuals have a substantial loss of bone mass in the lower limbs, equaling approximately 50% of normal values in the proximal tibia, and this has been associated with a high incidence of low impact fractures. To evaluate if this inactivity-associated condition in the SCI population can be reversed with prolonged physical training, ten SCI individuals [ages 35.3 +/- 2.3 years (mean +/- standard error [SE]); post injury time: 12.5 +/- 2.7 years, range 2-24 years; level of lesion: C6-Th4; weight: 78 +/- 3.8 kg] performed 12 months of Functional Electrical Stimulated (FES) upright cycling for 30 min per day, 3 days per week, followed by six months with only one weekly training session. Bone mineral density (BMD) was determined before training and 12 and 18 months later. BMD was measured in the lumbar spine, the femoral neck, and the proximal tibia by dual energy absorptiometry (DEXA, Nordland XR 26 MK1). Before training, BMD was in the proximal tibia (52%), as well as in the femoral neck, lower in SCI subjects than in controls of same age (P < 0.05). BMD of the lumbar spine did not differ between groups (P > 0.05). After 12 months of training, the BMD of the proximal tibia had increased 10%, from 0.49 +/- 0.04 to 0. 54 +/- 0.04 g/cm2 (P < 0.05). After a further 6 months with reduced training, the BMD in the proximal tibia no longer differed from the BMD before training (P > 0.05). No changes were observed in the lumbar spine or in the femoral neck in response to FES cycle training. It is concluded that in SCI, the loss of bone mass in the proximal tibia can be partially reversed by regular long-term FES cycle exercise. However, one exercise session per week is insufficient to maintain this increase.

Spinal cord injury (SCI) leads to severe bone loss in the paralysed limbs and to a resulting increased fracture risk thereof. Since long bone fractures can lead to comorbidities and a reduction in quality of life, it is important to improve bone strength in people with chronic SCI. In this prospective longitudinal cohort study, we investigated whether functional electrical stimulation (FES) induced high-volume cycle training can partially reverse the loss of bone substance in the legs after chronic complete SCI. Eleven participants with motor-sensory complete SCI (mean age 41.9+/-7.5 years; 11.0+/-7.1 years post injury) were recruited. After an initial phase of 14+/-7 weeks of FES muscle conditioning, participants performed on average 3.7+/-0.6 FES-cycling sessions per week, of 58+/-5 min each, over 12 months at each individual’s highest power output. Bone and muscle parameters were investigated in the legs by means of peripheral quantitative computed tomography before the muscle conditioning (t1), and after six (t2) and 12 months (t3) of high-volume FES-cycle training. After 12 months of FES-cycling, trabecular and total bone mineral density (BMD) as well as total cross-sectional area in the distal femoral epiphysis increased significantly by 14.4+/-21.1%, 7.0+/-10.8% and 1.2+/-1.5%, respectively. Bone parameters in the femoral shaft showed small but significant decreases, with a reduction of 0.4+/-0.4% in cortical BMD, 1.8+/-3.0% in bone mineral content, and 1.5+/-2.1% in cortical thickness. These decreases mainly occurred between t1 and t2. No significant changes were found in any of the measured bone parameters in the tibia. Muscle CSA at the thigh increased significantly by 35.5+/-18.3%, while fat CSA at the shank decreased by 16.7+/-12.3%. Our results indicate that high-volume FES-cycle training leads to site-specific skeletal changes in the paralysed limbs, with an increase in bone parameters at the actively loaded distal femur but not the passively loaded tibia. Thus, we conclude that high-volume FES-induced cycle training has clinical relevance as it can partially reverse bone loss and thus may reduce fracture risk at this fracture prone site.

OBJECTIVE: To determine whether bone mineral density loss after spinal cord injury can be attenuated by an early intervention with functional electrical stimulation cycling exercises (FESCE) and to ascertain whether the effect persists after FESCE is discontinued.

DESIGN: A prospective study.

SUBJECTS: Twenty-four individuals with spinal cord injury, 26-52 days after spinal cord injury, were divided into FESCE or control groups.

METHODS: FESCE was applied in the initial 3 months and then suspended in the subsequent 3 months. Bone mineral density in the femoral neck and distal femur was measured using dual energy X-ray absorptiometry before training, immediately after the initial 3 months of training, and at the end of the subsequent 3 months.

RESULTS: The bone mineral density decrease rate in the distal femur in the FESCE group was significantly less than that in the control group during the initial 3 months. However, there was no significant difference in the subsequent 3 months.

CONCLUSION: FESCE in the early stages of spinal cord injury can partly attenuate bone mineral density loss in the distal femur. However, bone mineral density loss in the distal femur cannot be ameliorated completely by FESCE. In addition, the effect on the attenuation of bone loss in the distal femur faded once FESCE was discontinued.

Functional electrical stimulation (FES) cycling ergometer has been utilized in recent decades for rehabilitation by sequentially stimulating the large leg-actuating muscles of paralyzed leg muscles to produce cyclical leg motion. A number of studies reported physiological adaptations after regular FES-cycling exercise (FESCE) training in subjects with spinal cord injury, stroke, cerebral palsy and other conditions. This article provides a comprehensive overview of general aspects of FES cycling systems and clinical applications of FESCE. The studies cited in this article provide supportive findings for the potential clinical efficacy of FESCE for reducing the risk of secondary medical complications in subjects with paralysis. The potential therapeutic benefits of FESCE include conditioning the cardiopulmonary, muscular, and skeletal systems, and improving other physiological and psychological performances. Our recent pilot study also indicated that the decrease of leg spasticity in subjects with cerebral palsy is one of the acute effects of FESCE. In conclusion, we recommend that FESCE is of benefit in a variety of aspects to improve the general condition and to prevent deterioration in subjects with central neurological impairments.

Endurance for dynamic exercise, cardiac output, blood pressure, heart rate, ventilation, and oxygen consumption was measured in eight individuals with paraplegia at the end of 4-min bouts of exercise on a friction braked cycle ergometer. Movement of the subjects’ legs was induced by electrically stimulating the quadriceps, gluteus maximus and hamstring muscles with a computer-controlled biphasic square — wave current at a frequency of 30 Hz. The friction braked cycle ergometer was pedalled at work rates which varied between 0 and 40 W. Measurements were repeated after 3 and 6 months to assess the affect of training. After 3 months of training it was found that endurance increased from 8 min at a work rate of 0 W to 30 min at a work rate of 40 W. Compared to the cardiovascular responses in non-paralyzed subjects, computerized cycle ergometry was found to be associated with higher relative stresses for a given level of absolute work. Mean blood pressure, for example, increased by over 30% during maximal work in individuals with paralysis compared to the typical response obtained for able-bodied subjects. Analysis of the data showed that instead of the 20-30% metabolic efficiency commonly reported for cycle ergometry, the calculated metabolic efficiency during computer-controlled cycle ergometry was only 3.6%.

Spinal cord injured (SCI) individuals most often contract their injury at a young age and are deemed to a life of more or less physical inactivity. In addition to the primary implications of the SCI, severe SCI individuals are stigmatized by conditions related to their physically inactive lifestyle. It is unknown if these inactivity related conditions are potentially reversible and the aim of the present study was, therefore, to examine the effect of exercise on SCI individuals. Ten such individuals (six with tetraplegia and four with paraplegia; age 27-45 years; time since injury 3-23 years) were exercise trained for 1 year using an electrically induced computerized feedback controlled cycle ergometer. They trained for up to three times a week (mean 2.3 times), 30 min on each occasion. The gluteal, hamstring and quadriceps muscles were stimulated via electrodes placed on the skin over their motor points. During the first training bouts, a substantial variation in performance was seen between the subjects. A majority of them were capable of performing 30 min of exercise in the first bout; however, two individuals were only able to perform a few minutes of exercise. After training for 1 year all of the subjects were able to perform 30 min of continuous training and the work output had increased from 4 +/- 1 (mean +/- SE) to 17 +/- 2 Kilo Joules per training bout (P < 0.05). The maximal oxygen uptake during electrically induced exercise increased from 1.20 +/- 0.08 litres per minute measured after a few weeks habituation to the exercise to 1.43 +/- 0.09 litres per minute after training for 1 year (P < 0.05). Magnetic resonance cross sectional images of the thigh were performed to estimate muscle mass and an increase of 12% (mean, P < 0.05) was seen in response to 1 year of training. In biopsies taken before exercise various degrees of atrophy were observed in the individual muscle fibres, a phenomenon that was partially normalized in all subjects after training. The fibre type distribution in skeletal muscles is known to shift towards type IIB fibres (fast twitch, fast fatiguable, glycolytic fibres) within the first 2 years after the spinal cord injury. The muscle in the present investigation contained of 63% myosin heavy chain (MHC) isoform IIB, 33% MHC isoform IIA (fast twitch, fatigue resistant) and less than 5% MHC isoform I (slow twitch) before training. A shift towards more fatigue resistant contractile proteins was found after 1 year of training. The percentage of MHC isoform IIA increased to 61% of all contractile protein and a corresponding decrease to 32% was seen in the fast fatiguable MHC isoform IIB, whereas MHC isoform I only comprised 7% of the total amount of MHC. This shift was accompanied by a doubling of the enzymatic activity of citrate synthase, as an indicator of mitochondrial oxidative capacity. It is concluded that inactivity-associated changes in exercise performance capacity and skeletal muscle occurring in SCI individuals after injury are reversible, even up to over 20 years after the injury. It follows that electrically induced exercise training of the paralysed limbs is an effective rehabilitation tool that should be offered to SCI individuals in the future.

OBJECTIVES: To determine if a hybrid exercise (leg plus arm) training program performed immediately after functional electrical stimulation (FES) leg cycle exercise (LCE) training would further improve aerobic capacity when compared with FES leg cycle training alone, and (2) to compare the submaximal responses occurring during both FES-LCE alone and hybrid exercise in the same SCI subjects.

DESIGN: Nonrandomized control trial whereby subjects act as their own control.

SETTING: Outpatient rehabilitation in a primary care hospital.

PATIENTS: A volunteer sample (n = 11) of men 20 to 50 years old with complete spinal cord injury, free from cardiovascular and metabolic disease with spasticity.

INTERVENTIONS: Three phases of exercise training: phase I, progressive FES-LCE to 30 minutes of exercise (n = 11); phase II, 35.2 +/- 16.2 sessions of FES-LCE (n = 11); phase III, 41.4 +/- 17.7 30-minute sessions of hybrid exercise (n = 8).

MAIN OUTCOME MEASURES: Aerobic capacity-a further increase after hybrid exercise when compared with FES-LCE alone; (2) submaximal physiologic parameters (oxygen uptake [VO2], heart rate [HR], blood lactate [BLa-])-measurement of these during constant work rate exercise and a training effect.

RESULTS: VO2 (the body’s ability to utilize oxygen) significantly improved (p < .05) after both FES-LCE and then further after hybrid training. Hybrid exercise training resulted in significantly (p < .05) greater work rates and VO2 values than both FES-LCE at baseline and training work rates.

CONCLUSION: These subjects demonstrated that hybrid exercise performed twice a week provided sufficient intensity to improve aerobic capacity and provide a medium whereby patients with SCI can burn more calories than via FES-LCE alone. This has important implications for improving the health and fitness levels of individuals with SCI and may ultimately reduce their risk of cardiovascular disease.

Two years of functional electrical stimulation cycling (FESC) as a researcher and subject have given me an insight into the direction that future FESC should take as well as providing me with significant health benefits and an enjoyable and functional ability to cycle. If FESC is to benefit spinal cord injured persons (SCIPs), researchers must turn their attention to making the activity convenient and enjoyable. What follows is a personal view and will be less scientifically rigorous than other presentations but hopefully still of value. It calls upon my experience as a general medical practitioner with a special interest in the value of exercise, a human powered vehicle enthusiast, an amateur FES researcher, but most importantly, an SCIP and FES cyclist.

OBJECTIVE: To determine the influence of pedaling cadence on cardiorespiratory responses and muscle oxygenation during functional electric stimulation (FES) leg cycling.

DESIGN: Repeated measures.

SETTING: Laboratory.

PARTICIPANTS: Nine subjects with T4 through T10 spinal cord injury (SCI) (American Spinal Injury Association grade A).

INTERVENTIONS: FES cycling was performed at pedaling cadences of 15, 30, and 50 revolutions per minute (rpm).

MAIN OUTCOME MEASURES: At each cadence, heart rate, oxygen uptake, and cardiac output were recorded during 35 minutes of cycling. Near infrared spectroscopy was used to quantify quadriceps muscle oxygenation.

RESULTS: All pedaling cadences induced similar elevations in cardiorespiratory metabolism, compared with resting values. Higher average power output was produced at 30rpm (8.2+/-0.7W, P<.05) and 50rpm (7.9+/-0.5W, P<.05) compared with 15rpm (6.3+/-0.6W). Gross mechanical efficiency was significantly higher (P<.05) at 30 and 50rpm than at 15rpm. Quadriceps muscle oxygenation did not differ with pedaling cadences.

CONCLUSIONS: Cardiorespiratory responses and muscle metabolism adjustments during FES leg cycling were independent of pedal cadence. FES cycling at a cadence of 50rpm may not confer any advantages over 30 or 15rpm for cardiovascular fitness promotion in persons with SCI.

Functional electrical stimulation (FES) cycling ergometer has been utilized in recent decades for rehabilitation by sequentially stimulating the large leg-actuating muscles of paralyzed leg muscles to produce cyclical leg motion. A number of studies reported physiological adaptations after regular FES-cycling exercise (FESCE) training in subjects with spinal cord injury, stroke, cerebral palsy and other conditions. This article provides a comprehensive overview of general aspects of FES cycling systems and clinical applications of FESCE. The studies cited in this article provide supportive findings for the potential clinical efficacy of FESCE for reducing the risk of secondary medical complications in subjects with paralysis. The potential therapeutic benefits of FESCE include conditioning the cardiopulmonary, muscular, and skeletal systems, and improving other physiological and psychological performances. Our recent pilot study also indicated that the decrease of leg spasticity in subjects with cerebral palsy is one of the acute effects of FESCE. In conclusion, we recommend that FESCE is of benefit in a variety of aspects to improve the general condition and to prevent deterioration in subjects with central neurological impairments.

FES leg cycling exercise is a physical activity that has potential to provide aerobic fitness and cardiovascular health benefits for individuals with SCI. However, there are few high-quality studies or systematic reviews for sufficient Level I or Level II evidence supporting the putative benefits of FES-evoked exercise after SCI, to make sound determination of its clinical efficacy to reduce obesity diabetes and cardiovascular disease. This paper samples some of the recent evidence supporting FES lower-limb exercise, by itself, and makes recommendations about how “critical dose-potency” might be achieved to provide clinical and health benefits from FES-exercise.

STUDY DESIGN: Prospective single-arm study.

OBJECTIVES: To investigate the effect of functional electrical stimulation (FES) cycling on late functional recovery, spasticity, gait parameters and oxygen consumption during walking in patients with chronic incomplete spinal cord injury (SCI).

SETTING: Turkish Armed Forces Rehabilitation Center, Ankara, Turkey.

METHODS: Ten patients with chronic (duration of more than 2 years) incomplete SCI who could ambulate at least 10 m independently or with the assistance of a cane or walker, but no hip-knee-ankle-foot orthosis. The subjects underwent 1-h FES cycling sessions three times a week for 16 weeks. Outcome measures including the total motor score, the Functional Independence Measure (FIM) score, the Modified Ashworth Scale for knee spasticity, temporal spatial gait parameters and oxygen consumption rate during walking were assessed at baseline, 3 and 6 months after the baseline.

RESULTS: There were statistically significant improvements in total motor scores, the FIM scores and spasticity level at the 6-month follow-up (P<0.01). The changes in gait parameters reached no significant level (P>0.05). Oxygen consumption rate of the patients showed significant reduction at only 6 months compared with baseline (P<0.01).

CONCLUSION: The results suggest that FES cycling may provide some functional improvements in the late period of SCI.

Endurance for dynamic exercise, cardiac output, blood pressure, heart rate, ventilation, and oxygen consumption was measured in eight individuals with paraplegia at the end of 4-min bouts of exercise on a friction braked cycle ergometer. Movement of the subjects’ legs was induced by electrically stimulating the quadriceps, gluteus maximus and hamstring muscles with a computer-controlled biphasic square — wave current at a frequency of 30 Hz. The friction braked cycle ergometer was pedalled at work rates which varied between 0 and 40 W. Measurements were repeated after 3 and 6 months to assess the affect of training. After 3 months of training it was found that endurance increased from 8 min at a work rate of 0 W to 30 min at a work rate of 40 W. Compared to the cardiovascular responses in non-paralyzed subjects, computerized cycle ergometry was found to be associated with higher relative stresses for a given level of absolute work. Mean blood pressure, for example, increased by over 30% during maximal work in individuals with paralysis compared to the typical response obtained for able-bodied subjects. Analysis of the data showed that instead of the 20-30% metabolic efficiency commonly reported for cycle ergometry, the calculated metabolic efficiency during computer-controlled cycle ergometry was only 3.6%.

Twelve patients were involved in a 3 month stimulation induced cycling programme at the Royal Perth Rehabilitation Hospital. A number of the patients were less than 1 year post injury, all except one had an incomplete injury, and most were receiving physiotherapy. All patients who completed the programme increased their time of cycling and, in all but one case, the exercise load, indicative of a local training effect. Significant improvements were found in voluntary isometric strength, stimulated isometric strength and stimulated isometric endurance of the quadriceps, muscle grading of the quadriceps and biceps femoris and the cross-sectional areas of the quadriceps and total thigh muscle. No change was found in voluntary isokinetic strength of the quadriceps. All patients with incomplete injuries reported improvements in the activities of daily living (ADL) after the programme. Bone mineral density (BMD) was examined in two patients, one less than 1 year post injury, and one greater than 4 years post injury. The programme of cycling did not restore BMD in the latter patient. However, while the former patient still displayed a reduced BMD after the programme, it is unknown whether this loss of bone was retarded. This needs further investigation. This study demonstrates the effectiveness of a combined physiotherapy/cycling programme in the rehabilitation of people with spinal injuries. To be successful this type of programme has to be incorporated into the rehabilitation process, as has been done at the Sir George Bedbrook Spinal Unit.

OBJECTIVES: To determine if a hybrid exercise (leg plus arm) training program performed immediately after functional electrical stimulation (FES) leg cycle exercise (LCE) training would further improve aerobic capacity when compared with FES leg cycle training alone, and (2) to compare the submaximal responses occurring during both FES-LCE alone and hybrid exercise in the same SCI subjects.

DESIGN: Nonrandomized control trial whereby subjects act as their own control.

SETTING: Outpatient rehabilitation in a primary care hospital.

PATIENTS: A volunteer sample (n = 11) of men 20 to 50 years old with complete spinal cord injury, free from cardiovascular and metabolic disease with spasticity.

INTERVENTIONS: Three phases of exercise training: phase I, progressive FES-LCE to 30 minutes of exercise (n = 11); phase II, 35.2 +/- 16.2 sessions of FES-LCE (n = 11); phase III, 41.4 +/- 17.7 30-minute sessions of hybrid exercise (n = 8).

MAIN OUTCOME MEASURES: Aerobic capacity-a further increase after hybrid exercise when compared with FES-LCE alone; (2) submaximal physiologic parameters (oxygen uptake [VO2], heart rate [HR], blood lactate [BLa-])-measurement of these during constant work rate exercise and a training effect.

RESULTS: VO2 (the body’s ability to utilize oxygen) significantly improved (p < .05) after both FES-LCE and then further after hybrid training. Hybrid exercise training resulted in significantly (p < .05) greater work rates and VO2 values than both FES-LCE at baseline and training work rates.

CONCLUSION: These subjects demonstrated that hybrid exercise performed twice a week provided sufficient intensity to improve aerobic capacity and provide a medium whereby patients with SCI can burn more calories than via FES-LCE alone. This has important implications for improving the health and fitness levels of individuals with SCI and may ultimately reduce their risk of cardiovascular disease.

STUDY DESIGN: Longitudinal training.

OBJECTIVES: To determine the effects of functional electrical stimulated (FES) leg cycle ergometer training on muscle histochemical characteristics in individuals with motor-complete spinal cord injury (SCI).

SETTING: University of Alberta, Edmonton, Alberta, Canada.

METHODS: Six individuals with motor-complete SCI (age 31-50 years; 3-25 years post-injury) trained using FES leg cycle ergometry for 30 min, 3 days per week for 8 weeks. Biopsies of the vastus lateralis muscle were obtained pre- and post-training and analyzed for fibre composition, fibre size and capillarization.

RESULTS: The majority of muscle fibres were classified as type 2 pre- and post-training. Average fibre area increased 23% (P<0.05) and capillary number increased 39% (P<0.05) with training. As a result of these proportional increases, capillarizatio expressed relative to fibre area was unchanged with training.

CONCLUSIONS: FES leg cycle ergometer training results in proportional increases in fibre area and capillary number in individuals with SCI.

OBJECTIVE: To test whether a short period of training leads to adaptations in the cross-sectional area of large conduit arteries and improved blood flow to the paralyzed legs of individuals with spinal cord injury (SCI).

DESIGN: Before-after trial.

SETTING: Rehabilitation center, academic medical center.

PARTICIPANTS: Nine men with spinal cord lesions.

INTERVENTION: Six weeks of cycling using a functional electrically stimulated leg cycle ergometer (FES-LCE).

MAIN OUTCOME MEASURES: Longitudinal images and simultaneous velocity spectra were measured in the common carotid (CA) and femoral (FA) arteries using quantitative duplex Doppler ultrasound examination. Arterial diameters, peak systolic inflow volumes (PSIVs), mean inflow volumes (MIVs), and a velocity index (VI), representing the peripheral resistance, were obtained at rest. PSIVs and VI were obtained during 3 minutes of hyperemia following 20 minutes of FA occlusion.

RESULTS: Training resulted in significant increases in diameter (p < .01), PSIVs (p < .01), and MIVs (p < .05), and reduced VI (p < .01) of the FA, whereas values in the CA remained unchanged. Postocclusive hyperemic responses were augmented, indicated by significantly higher PSIVs (p <.01) and a trend toward lower VI.

CONCLUSION: Six weeks of FES-LCE training increased the cross-sectional area of large conduit arteries and improved blood flow to the paralyzed legs of individuals with SCI.

The purpose of the present study was to determine the effect of a spinal cord injury (SCI) on resting vascular resistance in paralyzed legs in humans. To accomplish this goal, we measured blood pressure and resting flow above and below the lesion (by using venous occlusion plethysmography) in 11 patients with SCI and in 10 healthy controls (C). Relative vascular resistance was calculated as mean arterial pressure in millimeters of mercury divided by the arterial blood flow in milliliters per minute per 100 milliliters of tissue. Arterial blood flow in the sympathetically deprived and paralyzed legs of SCI was significantly lower than leg blood flow in C. Because mean arterial pressure showed no differences between both groups, leg vascular resistance in SCI was significantly higher than in C. Within the SCI group, arterial blood flow was significantly higher and vascular resistance significantly lower in the arms than in the legs. To distinguish between the effect of loss of central neural control vs. deconditioning, a group of nine SCI patients was trained for 6 wk and showed a 30% increase in leg blood flow with unchanged blood pressure levels, indicating a marked reduction in vascular resistance. In conclusion, vascular resistance is increased in the paralyzed legs of individuals with SCI and is reversible by training.

Two years of functional electrical stimulation cycling (FESC) as a researcher and subject have given me an insight into the direction that future FESC should take as well as providing me with significant health benefits and an enjoyable and functional ability to cycle. If FESC is to benefit spinal cord injured persons (SCIPs), researchers must turn their attention to making the activity convenient and enjoyable. What follows is a personal view and will be less scientifically rigorous than other presentations but hopefully still of value. It calls upon my experience as a general medical practitioner with a special interest in the value of exercise, a human powered vehicle enthusiast, an amateur FES researcher, but most importantly, an SCIP and FES cyclist.

OBJECTIVE: To assess the time course of arterial adaptations during 6 weeks of functional electric stimulation (FES) training and 6 weeks of detraining in subjects with spinal cord injury (SCI).

DESIGN: Intervention study (before-after trial). SETTING: University medical center.

PARTICIPANTS: Volunteer sample of 9 subjects with SCI.

INTERVENTIONS: Six weeks of twice weekly FES cycling and 6 weeks of detraining.

MAIN OUTCOME MEASURES: Vascular characteristics were measured by plethysmography (baseline and peak blood flow of the thigh) and echo Doppler (diameter of the femoral artery and flow-mediated dilation [FMD]).

RESULTS: After 2 weeks of FES training, arterial characteristics changed significantly; there was an increase in baseline and peak blood flow, an increase in femoral artery diameter, and a decrease in FMD of the femoral artery. Detraining reversed baseline and peak thigh blood flow, vascular resistance, and femoral diameter toward pretraining values within 1 week. However, detraining did not restore the FMD of the femoral artery, even after 6 weeks.

CONCLUSIONS: Two weeks of hybrid FES training (4 exercise bouts) is sufficient to improve peak leg blood flow and arterial diameter, and to normalize FMD. In addition, detraining results in rapidly reversed vascular characteristics within 1 week.

Functional electrical stimulation (FES)-induced leg exercise offers the potential for individuals with lower-limb paralysis to otherwise gain some benefits conferred by leg exercise. Although its original intent is to reactivate the leg muscles to produce functional upright mobility, as a rehabilitation therapy, FES-evoked exercise increases the whole-body metabolism of individuals with spinal cord injury (SCI) so that they may gain general and localized health and fitness benefits. The physiological and psychosocial responses during FES-evoked cycling, standing, rowing, leg extension, or stepping have been extensively explored for over 20 years. Some of the advantages of such exercise include augmented cardiorespiratory fitness, promotion of leg blood circulation, increased activity of specific metabolic enzymes or hormones, greater muscle volume and fiber size, enhanced functional exercise capacity such as strength and endurance, and altered bone mineral density. Positive psychosocial adaptations have also been reported among SCI individuals who undergo FES exercise. This article presents a position review of the available literature on the effects of FES-evoked exercise since the earliest date until 2007, to warrant a conclusion about the current status and potential of FES-evoked exercise for paralyzed people.

Functional electrical stimulation (FES) cycling ergometer has been utilized in recent decades for rehabilitation by sequentially stimulating the large leg-actuating muscles of paralyzed leg muscles to produce cyclical leg motion. A number of studies reported physiological adaptations after regular FES-cycling exercise (FESCE) training in subjects with spinal cord injury, stroke, cerebral palsy and other conditions. This article provides a comprehensive overview of general aspects of FES cycling systems and clinical applications of FESCE. The studies cited in this article provide supportive findings for the potential clinical efficacy of FESCE for reducing the risk of secondary medical complications in subjects with paralysis. The potential therapeutic benefits of FESCE include conditioning the cardiopulmonary, muscular, and skeletal systems, and improving other physiological and psychological performances. Our recent pilot study also indicated that the decrease of leg spasticity in subjects with cerebral palsy is one of the acute effects of FESCE. In conclusion, we recommend that FESCE is of benefit in a variety of aspects to improve the general condition and to prevent deterioration in subjects with central neurological impairments.

FES leg cycling exercise is a physical activity that has potential to provide aerobic fitness and cardiovascular health benefits for individuals with SCI. However, there are few high-quality studies or systematic reviews for sufficient Level I or Level II evidence supporting the putative benefits of FES-evoked exercise after SCI, to make sound determination of its clinical efficacy to reduce obesity diabetes and cardiovascular disease. This paper samples some of the recent evidence supporting FES lower-limb exercise, by itself, and makes recommendations about how “critical dose-potency” might be achieved to provide clinical and health benefits from FES-exercise.

PURPOSE: Individuals with spinal cord injuries (SCI) have an increased prevalence of insulin resistance and type 2 diabetes mellitus. In able-bodied individuals, training with large muscle groups increases insulin sensitivity and may prevent type 2 diabetes mellitus. However, individuals with SCI cannot voluntarily recruit major muscle groups, but by functional electrical stimulation (FES) they can now perform ergometer bicycle training.

METHODS: Ten subjects with SCI (35 +/- 2 yr (mean +/- SE), 73 +/- 5 kg, level of lesion C6–Th4, time since injury: 12 +/- 2 yr) performed 1 yr of FES cycling (30 min x d(-1), 3 d x wk(-1) (intensive training)). Seven subjects continued 6 months with reduced training (1 d x wk(-1) (reduced training)). A sequential, hyperinsulinemic (50 mU x min(-1) x m(-2) (step 1) and 480 mU x min(-1) x m(-2) (step 2)), euglycemic clamp, an oral glucose tolerance test (OGTT), and determination of GLUT 4 transporter protein in muscle biopsies were performed before and after training.

RESULTS: Insulin-stimulated glucose uptake rates increased after intensive training (from 4.9 +/- 0.5 mg x min(-1) x kg(-1) to 6.2 +/- 0.6 mg x min(-1) x kg(-1) (P < 0.008) (step 1) and from 9.0 +/- 0.8 mg x min(-1) x kg(-1) to 10.6 +/- 0.8 mg x min(-1) x kg(-1) (P = 0.103) (step 2)). With the reduction in training, insulin sensitivity decreased to a similar level as before training (P > 0.05). GLUT 4 increased by 105% after intense training and decreased again with the training reduction. The subjects had impaired glucose tolerance before and after training, and neither glucose tolerance nor insulin responses to OGTT were significantly altered by training.

CONCLUSIONS: Electrically induced bicycle training, performed three times per week increases insulin sensitivity and GLUT 4 content in skeletal muscle in subjects with SCI. A reduction in training to once per week is not sufficient to maintain these effects. FES training may have a role in the prevention of the insulin resistance syndrome in persons with SCI.

DESIGN: Longitudinal training.

OBJECTIVES: The purpose was to determine the effect of electrical stimulation (ES)-assisted cycling (30 min/day, 3 days/week for 8 weeks) on glucose tolerance and insulin sensitivity in people with spinal cord injury (SCI).

SETTING: The Steadward Centre, Alberta, Canada.

METHODS: Seven participants with motor complete SCI (five males and two females aged 30 to 53 years, injured 3-40 years, C5-T10) underwent 2-h oral glucose tolerance tests (OGTT, n=7) and hyperglycaemic clamp tests (n=3) before and after 8 weeks of training with ES-assisted cycling.

RESULTS: Results indicated that subjects’ glucose level were significantly lower at 2 h OGTT following 8 weeks of training (122.4+/-10 vs 139.9+/-16, P=0.014). Two-hour hyperglycaemic clamps tests showed improvement in all three people for glucose utilisation and in two of three people for insulin sensitivity.

CONCLUSIONS: These results suggested that exercise with ES-assisted cycling is beneficial for the prevention and treatment of Type 2 diabetes mellitus in people with SCI.

Persons with spinal cord injury (SCI) are at a heightened risk of developing type II diabetes and cardiovascular disease. The purpose of this investigation was to conduct an analysis of metabolic, body composition, and neurological factors before and after 10 weeks of functional electrical stimulation (FES) cycling in persons with SCI. Eighteen individuals with SCI received FES cycling 2-3 times per week for 10 weeks. Body composition was analyzed by dual X-ray absorptiometry. The American Spinal Injury Association (ASIA) neurological classification of SCI test battery was used to assess motor and sensory function. An oral glucose tolerance (OGTT) and insulin-response test was performed to assess blood glucose control. Additional metabolic variables including plasma cholesterol (total-C, HDL-C, LDL-C), triglyceride, and inflammatory markers (IL-6, TNF-alpha, and CRP) were also measured. Total FES cycling power and work done increased with training. Lean muscle mass also increased, whereas, bone and adipose mass did not change. The ASIA motor and sensory scores for the lower extremity significantly increased with training. Blood glucose and insulin levels were lower following the OGTT after 10 weeks of training. Triglyceride levels did not change following training. However, levels of IL-6, TNF-alpha, and CRP were all significantly reduced.

Functional electrical stimulation (FES) cycling ergometer has been utilized in recent decades for rehabilitation by sequentially stimulating the large leg-actuating muscles of paralyzed leg muscles to produce cyclical leg motion. A number of studies reported physiological adaptations after regular FES-cycling exercise (FESCE) training in subjects with spinal cord injury, stroke, cerebral palsy and other conditions. This article provides a comprehensive overview of general aspects of FES cycling systems and clinical applications of FESCE. The studies cited in this article provide supportive findings for the potential clinical efficacy of FESCE for reducing the risk of secondary medical complications in subjects with paralysis. The potential therapeutic benefits of FESCE include conditioning the cardiopulmonary, muscular, and skeletal systems, and improving other physiological and psychological performances. Our recent pilot study also indicated that the decrease of leg spasticity in subjects with cerebral palsy is one of the acute effects of FESCE. In conclusion, we recommend that FESCE is of benefit in a variety of aspects to improve the general condition and to prevent deterioration in subjects with central neurological impairments.

FES leg cycling exercise is a physical activity that has potential to provide aerobic fitness and cardiovascular health benefits for individuals with SCI. However, there are few high-quality studies or systematic reviews for sufficient Level I or Level II evidence supporting the putative benefits of FES-evoked exercise after SCI, to make sound determination of its clinical efficacy to reduce obesity diabetes and cardiovascular disease. This paper samples some of the recent evidence supporting FES lower-limb exercise, by itself, and makes recommendations about how “critical dose-potency” might be achieved to provide clinical and health benefits from FES-exercise.