Effectiveness of visual feedback during isokinetic exercise

Although previous investigators have observed that knowledge of performance via visual feedback tends ro enhance performance during an isokinetic test, the time frame over which visual feedback remains advantageous is unclear. The purpose of this study was to compare knee extensor torques produced by visual feedback and no visual feedback groups on three occasions, completed over a 2-week period, and at 4 weeks after the third rest. Healthy, sedentary subjects were each randomly assigned to either a visual feedback or a no visual feedback group (N = 10 males and 10 females per group). Visual feedback consisted of viewing a computer monitor which displayed the current and a target knee extension force. Torques produced by the visual feedback group were consistently greater (p < 0.05) and more reliable than those produced by the no visual feedback group. The effectiveness of visual feedback tended to decrease over the first three occasions, suggesting thar visual feedback may not be as advantageous once a skill is well learned. Further research needs to examine the contribution of visual feedback to motor learning as well as retention and transfer of motor skills during more complex functional tasks.