ELECTRICAL ACTIVITY OF HUMAN MOTOR UNITS DURING VOLUNTARY CONTRACTION

Publisher Website
Google Scholar
Abstract
Action potentials from single motor units were studied during various strengths of contraction, sustained effort and fatigue. No electrical activity was observed in a relaxed muscle. 2 means of grading the strength of a contraction, namely, change in frequency of discharge in each unit and in number of units active, were shown to operate throughout the range of contraction intensities. The lowest regular frequency of motor unit response found during voluntary contraction was 3 per sec., the highest frequency 50 per sec. Motor units kept continuously active for 15-30 min. showed no sign of rotational activity or variation in frequency or amplitude. During fatigue single motor unit responses progressively diminished in amplitude but maintained the same frequency.

This publication has 7 references indexed in Scilit: