Isokinetic training — also called isovelocity training — requires a special machine that keeps the muscle contracting at a constant pace. Isokinetics combine isometric and isotonic contractions. This kind of training allows for maximal strength improvements and is usually combined with other types of strength training.
Because the equipment used in isokinetic training constantly monitors the exertion of the user, the resistance can be altered to keep a constant contraction on the muscles without risk of overtraining or injury. This type of training is especially helpful in rehabilitation scenarios where the person is at high risk for re-injury. Another benefit of isokinetic exercise is improved range of motion — particularly in the legs — and improved balance. Finally, isokinetic training can help a person's body prepare for more strenuous exercise, such as before beginning a new weightlifting program.
During an initial rehab visit, the therapist will use a dynamometer machine to both apply continual pressure and to measure exertion. Other scenarios in which these machines might be used are to test muscular performance in pro athletes and rehab situations where a person is learning to use a new prosthetic limb.
The areas of the body which benefit from isokinetic testing or training are the shoulder, elbow, wrist, hip, knee and ankle. The patient's familiarity with the machine may influence the outcome, so many clinics offer the patient time to become acquainted with how the machine works before beginning the test or exercise.
Most isokinetic machines are prohibitively expensive — so much so, that many gyms cannot afford them. They are most often found in professional rehabilitation centers. These machines may be either electronic resistance or hydraulic resistance. Less expensive machines may be purchased for gym or home use. One example of an isokinetic machine is an exercise bike that offers computer programs that can limit the number of revolutions performed per minute.
Just as there are benefits to isokinetc training, there are also cons. These include the high cost of the machines, the level of skill and training required to operate the more advanced machines and the time involved. Another downfall of this type of training is that there is some question as to the functionality of isokinetic training.