The purpose of this study was to elucidate if the m. quadriceps femoris was fully
activated during the first contractions of a series of repetitive maximal contractions
and if there was any difference in the development of fatigue between sexes. To do
this sixteen untrained subjects performed two series of contractions in an isokinetic
dynamometer: one series of single maximum contractions and one series of repetitive
maximum contractions. The EMC activity of m. vastus lateralis, m. vastus medialis
and m. rectus femoris was recorded. The subjects were unable to perform maximum effort
during the first repetitions of each trial, which might influence the results of fatigue
studies, if these contractions are chosen as reference. We also found in contrast
to other studies a decrease in RMS between the reference contraction and the fatigue
level. We have not been able to display any difference between males and females during
fatigue either in relative mechanical output nor in electromyographic parameters or
experience in fatigue during isokinetic knee-extensions.
Key words
Mechanical output - electromyography - isokinetic - knee-extensions - males - females