The effect of wrist position, angular velocity, and exertion direction on simultaneous maximal grip force and wrist torque under the isokinetic conditions

The objective of the study was to identify the effects of wrist position, force exertion direction, and angular velocity on simultaneous grip force and wrist torque under the isokinetic condition. Twenty-five male students participated in the study and the isokinetic wrist dynamometer was utilized to measure both forces from 90° of flexion to 90° of extension in the slow velocities of 10°/s, 20°/s, and 30°/s. The results revealed that grip force and wrist torque were larger around neutral and there was a passive force in the extremely extended wrist position. Wrist torque only was higher in the flexion direction but grip force for both directions did not differ significantly. Both grip force and wrist torque decreased when angular velocities increased and velocities could be classified into three groups, such as isometric, 5-20°/s, over 25°/s, according to the magnitude of force reduction. Finally, it was described that wrist positions, where maximal grip force and wrist torque occurred, were inconsistent and significant ranges of the wrist position including maximal forces were broad under the isokinetic condition of even slow velocities.