Abstract
The purpose of this study was to determine the torque-velocity relationship between concentric and eccentric contraction of elbow flexor muscles. Elbow flexor torques of nine healthy men (29.3±8.7ys) were measured during concentric and eccentric contraction with an isokinetic dynamometer at velocities of 10, 30, 60 and 120deg./sec. Peak torque at each velocity of nine subjects was measured to determine the torque -velocity relationship. And the ratio of peak torque of concentric contraction to that of eccentric contraction (EMC/CMC) was calculated. Stabilization straps were used to prevent the shoulder and girdle sliding in order to prevent the error between movement of arm and movement of dynamometer. The significant difference was observed between the torque of concentric and eccentric contraction at the same angular velocity (p<0.001). At the eccentric contraction the torque at 10deg/sec was significantly lower than that at 30, 60, 120deg/sec (p<0.01). At the concentric contraction the torque reached the maximum at 30deg/sec. But no significant change of the torque was observed at concentric contracton. Significant difference existed between EMC/CMC ratio at 10deg/sec and that at 30, 60 and 120deg/sec (p<0.001).
From these findings the following conclusion can be reached that the difference existed between the torque of concentric and eccentric contraction. The greater torque of EMC than that of CMC might be the result of fascilitation of motor unit due to long loop reflex during the stretch of muscle. The follwing fact was reported that stretch of the twitched single muscle fiber caused the enhancement of muscle fiber force. These mechanism may explain the result in this study.
