Neuromuscular testing
twitch, muscle fatigue
CONTRACTIONS
Central and peripheral contributions to muscle fatigue, 5–10 min before and 1 min after each exercise test (TTE), were examined by superimposing a supramaximal magnetic stimulation of the femoral nerve during and 5 s after a series of maximal voluntary contractions (MVCs) of the quadriceps. Participants sat in a semi-reclined position on a table, with the upper body and lower back supported at a hip angle of 45°, and the knee joint angle set at 90° of flexion with the arms folded across the chest. A magnetic stimulator (Magstim 200Maximal femoral nerve stimulation was verified in each participant by assessing unpotentiated quadriceps single twitch forces obtained at 70%, 80%, 85%, 90%, 95%, and 100% of maximal stimulator output. A plateau in baseline unpotentiated quadriceps single twitch force with increasing stimulus intensities was observed in every participant and a plateau in M-wave amplitudes was observed in the sub-set of participants in which EMG was recorded. The stimulator was set at 100% for all participants and trials.A superimposed twitch force during and a potentiated force (