Abstract
The aim of this study was to compare the effect of isokinetic contraction mode and velocity on the torque-angle relationship during maximum voluntary elbow flexion in patients with stroke, age-matched healthy subjects and young subjects. To eliminate the effect of torque amplitude differences between subjects and groups, the torque values throughout the ROM were individually normalized to the peak value for each contraction velocity. The results indicate that in stroke patients the normalized torque angle relationship during the eccentric contractions was better preserved than during concentric contractions. Specifically, during eccentric contractions, stroke patients exhibited a torque-angle relationship that was closer to normal as the test velocity increased. The opposite trend could be seen in concentric contractions where the torque-angle relationship became more divergent from normal with a rise in the velocity. The torque-angle relationships were essentially the same for the control groups, irrespective of contraction mode or velocity. These findings may have significance for loading patterns of resistance training exercises used with stroke patients as such exercises normally are biomechanically designed for normal torque angle relationships. In clinical practice, these findings may partly explain why the strength increases due to resistance training are limited for patients with stroke.