The term isokinetics describes a process in which a body segment accelerates to achieve a
pre-selected fixed speed against an accommodating resistance. No matter how much force is
exerted by the patient, segment velocity will not exceed the pre-selected speed, the resistance
varies to exactly match the force applied at every point in the range of motion. The amount of
force applied by the patient can be measured in foot-pounds or Newton-Meters of torque and
is represented both numerically and graphically. When accurately measured, this can be used
as a basis for comparison of test results. Cybex isokinetic testing can thus be used to identify
and quantify functional musculoskeletal deficits.

Over 20 years of independent clinical research have proven Cybex isokinetic testing to be
accurate, objective, reproductive and safe. Because isokinetic resistance accommodates
perfectly to the patient’s torque output, the risk of overloading a tested joint is greatly
minimized. Any reduction in force output due to pain or weakness results in an immediate
reduction in resistance. This reduction is measured and graphed, enabling the clinician
to determine where in the range of motion a deficit exists. Additionally, consistency of
performance is reflected in the reproducibility of an individual’s torque curve. Maximal efforts
generally produce uniform curves, whereas sub-maximal efforts may result in curves of variable shape and amplitude.