The theory behind isokinetic testing is muscle movement isolation.
Isokinetic dynamometers are able to test the strength (torque) and power of different muscle groups. The equipment can be modified in order to assess a number of different upper and lower body limb motions. The isokinetic dynamometer isolates the joint of interest, which allows targeted testing of particular muscle groups. In addition to this, settings can be changed to evaluate muscle performance across differing speeds and particular ranges of motion and can accommodate isometric, isokinetic, and isotonic (both eccentric and concentric) muscle action.