Recruitment of motor units in human forearm extensors.

摘要: 1. Experiments were conducted on single motor units of two forearm muscles, extensor carpi radialis (ECR) and digitorum communis (EDC) human subjects. Our interest was whether or not task groups could be identified in these and, if so, there orderly recruitment within each group. 2. To test for the presence separate ECR, motor-unit examined isometric contractions:wrist extension radial deviation. Each ECR tested repeatedly discharged during contractions both directions, indicating absence directions. 3. Recruitment order between pairs action potentials wrist For 58 paired comparisons, same In terms force output, plots twitch torque versus threshold showed a positive correlation deviation, demonstrating size-ordered motoneurons contractions. 4. The EDC motoneuron pool exhibited partially overlapping subpopulations basis task, one subpopulation recruited middle finger second ring extension. Contractions involving index little fingers examined. It is concluded that do exist pool. Plots correlations groups.(ABSTRACT TRUNCATED AT 250 WORDS)