Sources of error in isokinetic dynamometry: effects of visual feedback on maximum torque.

The purpose of this study was to examine the effects of visual feedback on isokinetic maximum torque and reciprocal muscle group ratio of the knee extensors and flexors at a slow (60 degrees /set) and a fast (180 degrees /sec) speed of movement. The real-time gravity-corrected torque output, used as the visual feedback source, elicited a significant increase in the maximum torque output of both muscle groups at the slow speed. There was no improvement at the fast speed of movement. The knee flexor/extensor ratio was not effected by visual feedback or speed of movement. It was concluded that visual feedback of the torque output can improve maximum voluntary contraction in isokinetic dynamometry under certain restrictions on speed and range of movement. J Orthop Sports Phys Ther 1991;13(3):138-142.

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