Reliability of measurements of concentric and eccentric isokinetic loading

The purpose of this study was to assess the reliability of a method for testing peak torque and work output of the knee extensor muscle during concentric and eccentric loading at three velocities of exercise (60°, 120°, and 180°/sec). Fourteen healthy men (23-32 years of age) performed exercises of the quadriceps femoris muscles during concentric and eccentric loading, with a five-second pause between each contraction. Three different tests were performed on different occasions. The first exercise session was a practice session, and the next two sessions were established to collect data in a test-retest format. Peak torque and work were measured for the two testing sessions. The results of this study demonstrated that with a very specific protocol, the reliability of concentric peak torque and work measurements was excellent at 60° and 120°/sec and good at 180°/sec. In contrast, reliability of eccentric peak torque and work measurements was good at 120° and 180°/sec but low at 60°/sec.