Force Versus Electromyographic (EMG) Signals for Biofeedback in Isometric Training

The volunteers will perform three maximal voluntary isometric contractions of six seconds each with a period of 120 seconds of rest between each contraction and both force and eletromyographic siganls will be recorded during this assessment without visual and verbal feedback. After 10 minutes, training will be performed with series of maximal voluntary isometric contractions of six seconds duration each with a period of 120 seconds of rest between each contraction and 180 seconds of rest between each serie with visual feedback. In each of them volunteers were encouraged to surpass 10 % (updated for each new series) of the reference value. If the volunteer was not able to reach this value in the next series, an adjustment was made lowering 5 % and, if they failed again, training was halt at this point. After training force and eletromyographic signals will be compared.