The Benefits of Isokinetic Cycling

What is isokinetic cycling?

Isokinetic means “constant speed.” So isokinetic cycling means cycling at a constant speed or pedaling at a constant cadence, despite changing load or resistance. Imagine you’re pedaling a stationary bike at a constant cadence of 50 revolutions per minute (rpm), and, say, at resistance Level 1. If your goal was to maintain that 50 rpm and someone came along and suddenly increased the resistance to Level 5, you’d pedal harder to keep up your pace. In this case, the resistance changed, but you kept the speed constant, so you were doing isokinetic cycling.

Normal exercise bikes are isotonic, which means “constant force” or “constant resistance.” In other words, normal exercise bikes provide constant resistance while you pedal at whatever speed you like. You can change the resistance to a particular level, but most of the time you’re pedaling with constant resistance. In fact, most exercises people perform are isotonic, including lifting weights or running on a treadmill, because the resistance remains constant throughout the motion.

An isokinetic exercise bike automatically changes the resistance to maintain a constant cadence. Imagine you’re pedaling an isokinetic exercise bike. Instead of selecting a resistance, you select a speed, like 50 rpm. When you start pedaling, the bike will offer no resistance, so you’ll reach 50 rpm easily. However, as soon as you try to pedal faster than 50 rpm, the bike ramps up the resistance, preventing you from going any faster. The harder you pedal, the more the bike resists. Traditionally, if you pedaled slower than 50 rpm, the bike just stops resisting. However, a truly isokinetic exercise bike will actually help you pedal if you’re going too slow, using a motor connected to the pedals. You could actually relax and do nothing, and the bike would passively rotate your legs at the speed you want.

What are the benefits?

Isokinetic exercise has many benefits, especially for rehabilitation.

Isotonic exercise can often be jerky, especially if the person isn’t able to perform the exercise very well because of an injury or disorder. Jerky movements, especially under load, can easily cause muscle strains or joint damage. In contrast, isokinetic exercises always involve smooth, controlled motions, minimizing jerkiness and reducing the likelihood of injury. Because an isokinetic motion is so well-controlled, isokinetic exercise enables a trainer or therapist to precisely control the amount of work that the patient is doing, which makes optimizing and tracking workouts that much easier.

True isokinetic exercise, where the equipment assists the person in performing the movement if they do it too slowly, is especially beneficial for people with muscle weakness, paralysis, or some other movement disorder. For example, recent research is demonstrating the benefits of “forced exercise” – isokinetic cycling at a rate that’s faster than the person can do on their own – for people with Parkinson’s disease. The studies are showing that the effects of forced exercise for people with Parkinson’s disease are similar to those seen with medication [1]. Even being able to pedal without volitional effort is beneficial, as it can help relieve joint stiffness and muscle spasticity.

The key benefit of using an isokinetic exercise bike is that it always provides just the right amount of assistance or resistance to help you pedal at the optimal speed. You get out exactly what you put in, and no matter how hard you work, the motion will always be smooth and controlled. If you need help getting up to speed, it gives you exactly the amount of assistance you need and no more.

The MyoCycle is one of the only isokinetic cycling systems in the world, and it is the only FES bike that is isokinetic. A silent, built-in electric motor provides isokinetic control at 35 rpm – a speed that is especially effective for use with FES, as it balances muscle and strength gains with cardiovascular benefits [2]. The MyoCycle can be used with or without the FES, making a flexible, FES-enhanced isokinetic cycling system perfect for rehabilitation for people with neurological disorders or orthopedic conditions.

References:

[1] Beall EB, Lowe MJ, Alberts JL, et al. The Effect of Forced-Exercise Therapy for Parkinson’s Disease on Motor Cortex Functional Connectivity. Brain Connectivity. 2013;3(2):190-198. doi:10.1089/brain.2012.0104.

[2] Fornusek C, Davis GM, Russold MF. Pilot Study of the Effect of Low-Cadence Functional Electrical Stimulation Cycling After Spinal Cord Injury on Thigh Girth and Strength. Archives of Physical Medicine and Rehabilitation. 2013;94(5):990-993. doi: 10.1016/j.apmr.2012.10.010.