Motor unit activity during isometric and concentric-eccentric contractions of the human first dorsal interosseus muscle

摘要: 1. Motor unit activity was recorded with intramuscular fine wire electrodes during isometric, concentric, and eccentric in the human first dorsal interosseus muscle. Twenty-one units from 11 subjects were sampled. 2. During isotonic cycles of shortening lengthening, 18 21 recruited concentric phase, increased their discharge rates as movement progressed, then decreased rate derecruited. 3. A different pattern recruitment observed recordings three units. These at a time when other decreasing or being In two selectively it possible to determine isometric thresholds, which higher than those exhibiting more common recruitment. 4. For selective contraction, simultaneously pairs recording wires separated by 5-10 mm. Each these detected both electrodes, making unlikely that artifact responsible for initiation cessation discharge. 5. The patterns suggest changes type distribution synaptic inputs motoneurons can, some instances, override pre- postsynaptic factors shape order conditions.