抄録
There are neuromusclular and perceptual constraints in the coordinated movements of the limbs. The movement of a limb therefore can be affected by that of other limbs and vice versa. In the present study, we investigated the interaction between the contraction of the hand muscle (wrist extensor) and the relaxation of the foot muscle (ankle dorsiflexor) on the ipsilateral (right) side. Subjects sat like sitting on an armchair, which enabled them to move their wrist and ankle freely, and performed five tasks: task 1) active wrist extension from a wrist flexed (relaxed) position to the horizontal position, task2) active ankle dorsiflexion from a ankle planarflexed (relaxed) position to a moderately dorsiflexed position, task3) passive plantarflexion from the moderately dorsiflexed position to the relaxed position, task 4) simultaneously doing tasks 1 and 2, and task 5) simultaneously doing tasks 1 and 3. Subjects performed each task as fast as possible and were instructed not to plantarflex actively in tasks 3 and 5. The mean and maximal wrist angle velocity, and the electromyographic activity of the wrist extensor in task 5 were smaller than those in task 1. The relaxation of the ankle dorsiflexor occurred more slowly in task 5 than that in task 3. The electromyographic activity of plantarflexors in task 5 was greater than that in task 3. It is suggested that the simultaneous hand muscle contraction and foot muscle relaxation on the ipsilateral side interfere with each other. [J Physiol Sci. 2007;57 Suppl:S161]
