Effects of Knowledge of Results on Reciprocal, lsokinefk Strength and Fatigue.

The purpose of this study was to determine the effects of knowledge of results, i.e., visual feedback from watching the torque curve on the Cybex II recorder, on knee extensor and flexor strength (peak torque in ft-lb), and fatigue (strength decrement) during reciprocal, isokinetic testing at speeds of 15O/sec (slow) and 300 degrees /sec (fast). Knowledge of results induced higher strength and fatigue values in both muscle groups during slow, but not fast, speed tests. The greater amounts of fatigue resulted from elevated initial strength levels at the beginning of the slow speed fatigue tests. The superior quality of the slow speed knowledge of results and longer times to utilize the visual feedback may explain the enhanced strength values. The effect of knowledge of results on strength levels decreased during the course of the slow speed fatigue tests. Results are discussed in terms of information processing and motivation theory. J Orthop Sports Phys Ther 1984;6(3):190-197.