Electrical activity in voluntarily contracting muscle.
The collision technique was used to determine the relationship between the electrical potential and the force produced by a voluntarily contracting first dorsal interosseus muscle. The method allows, in effect, synchronization of nerve impulses of asynchronously firing motoneurons subserving voluntary contraction. A compound muscle action potential, M (voluntary), thus recorded as an electrical corollary of muscle contraction, related linearly to the force of contraction under isometric conditions. Using M(voluntary), an approximate percentage of motoneuron pool discharging during a 10-msec period was calculated at various levels of voluntary effort. In ten healthy subjects, it increased linearly  with muscle force from 2.4% +/- 1.4% at 0.5 kg to 23.5% +/- 9.6% at 4.5 kg.
D000200:Action Potentials; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D009046:Motor Neurons / Q000502:physiology; D009119:Muscle Contraction; D011930:Reaction Time