Reliability of maximum static work efforts by the human masseter muscle.

To study the reliability of nonfatiguing maximum voluntary static work efforts by the masseter muscle, six healthy subjects exercised teeth clenching in centric occlusion. Maximum voluntary teeth clenching was performed for 10 seconds on 2 different days, each with two trials, and maximum static work efforts (without artificial feedback-control) were quantified by integrated surface electromyography. Reliability was determined by factorial analyses of variance and intraclass correlations. Data reduction showed that maximum voluntary static work efforts were reproduced reliably during the four different trials.