ABSTRACT
Evaluation of the effect of sustained muscular contractions is of interest in a multitude of situations. Examples in clinical medicine include pain syndromes linked to the involuntary building up of muscular tension, for instance localized to the trapezius or the masseter muscles. In ergonomics the problems associated with sustained muscular load play a profound role. This is due to the fact that prolonged muscular effort, particularly at high levels of voluntary activation, evokes pain and discomfort, that the biomechanical loading on body structures may cause tissue damage in the long run, and that muscular fatigue may impair the possibility to carry out the working task as required. Muscle fatigue also enhances tremor and reduces fine motor control.
