Isokinetic strength aspects of human joints and muscles.

The need to develop objective methods for determining muscle strength has been a major concern in rehabilitation, biomechanics, work physiology, and other related research areas for several decades. Because of the growing need for better standardization and control of resistive exercises in dynamic conditions, not only in clinical but in research settings also (as training/testing devices, and as a method for scientific evaluation of the force-velocity relationship), development of special devices or dynamometers using computerized techniques became relevant. This article examines the perspectives of muscle function with respect to the particular characteristics of strength and velocity in general and to isokinetic strength aspects in particular in human joints and muscles. The "isokinetic" movement condition as a tool for assessing and rehabilitating strength, clinical, and ergonomic applications, and the limitations of the methodology, is critically reviewed.