FIRING RATE ANALYSIS USING DECOMPOSITION-ENHANCED SPIKE TRIGGERED AVERAGING IN THE QUADRICEPS FEMORIS

Electromyographic signals detected from the quadriceps femoris during various constant force contractions were decomposed to identify indivi dual motor unit discharges and mean firing rates (FRs). Subject and gr oup mean FRs were calculated for each force level. Mean FR values and FR variability increased with force. Individual, subject, and group me an FRs showed slight increases until 30% of maximum voluntary contract ion and larger increases thereafter. Findings are discussed in relatio n to motor unit recruitment, frequency modulation, and fatigue. (C) 19 98 John Wiley & Sons, Inc.