The conduction velocity as a muscular fatigue indicator during isokinetic contractions

The present work investigated the behavior of conduction velocity of muscle fiber action potential of the vastus lateralis muscle through the acquisition of surface electromyographic signals during the knee isokinetic extension movement. Nine healthy male subjects performed three sets of ten maximal concentric knee extensions at 60^o/s with a rest interval of one minute between the sets. The linear regression of conduction velocity was determined for each repetition of each set. Despite of its positive value, the slope of the straight lines was gradually decreasing along the repetitions of each set, what suggests that the subjects were reaching a fatigue state.