RESISTIVE ECCENTRIC EXERCISE - EFFECTS OF VISUAL FEEDBACK ON MAXIMUM MOMENT OF KNEE EXTENSORS AND FLEXORS

One of the most important features of isokinetic dynamometry is the ac curate assessment of muscular function. One of the main factors affect ing the accuracy oi isokinetic parameters during maximum activation ef forts is visual feedback. The purpose of this study was the examinatio n of the effects of visual feedback on maximum moment measurements oi the knee extensors and flexors during isokinetic eccentric activations . Twenty-five males performed five maximal efforts at angular velociti es of 30 degrees/sec and 150 degrees/sec with and without visual feedb ack on a Biodex dynamometer. Visual feedback was provided as real time display of the moment output. A three-factor analysis of variance tes t revealed significant differences between the moments recorded with v isual feedback and the nonvisual feedback maximum moments of knee exte nsors and flexors at both speeds. The mean extension peak moments at 3 0 degrees/sec and 150 degrees/sec under visual feedback condition were approximately 7.2 and 6.4% higher than the nonvisual feedback moments , respectively. The increase for the knee flexor moment was 8.7 and 9% for slow and fast speeds, respectively. These findings suggest that v isual feedback can improve maximum eccentric output and should be prov ided during assessment of maximum eccentric strength on an isokinetic dynamometer.