Abstract
Robotic isokinetic dynamometry has become a standard modality in orthopedic assessment and rehabilitation. The advent of computerized dynamometry has allowed the incorporation of visual feedback into the testing and training of isolated muscle groups. Visual feedback provides objective information, motivation, and behavior reinforcement regarding an individual's motor response. Research on the use and effect of visual feedback as an adjunct to muscle performance, rehabilitation, and isokinetics in particular has been limited. This study was designed to explore the effect of visual feedback on force production of the quadriceps muscles in both the dominant and nondominant extremity. Slow (30 deg/sec) and moderate (120 deg/sec) speeds were compared as well as three versus five repetitions. Twenty-seven subjects (15 female and 12 male) were randomly assigned to vision and nonvision groups. Each subject participated in two tests at a 1-week interval with and without visual feedback from a computer monitor. Results demonstrated significantly higher (p < 0.01) force production when receiving visual feedback. Significance was achieved regardless of testing order. In conclusion, when seeking peak torque or peak average force production, visual feedback is facilitative. Similarly, when maximal effort is desired during rehabilitation, visual feedback could be an effective adjunct to usual clinical procedure.