Facial pain in negative and positive work of human jaw muscles

Ten healthy human male subjects with a mean age of 21 years performed negative and negative/positive work with the jaw muscles for about 21 min. The average amount of negative work was 13.3 kgm, while that of negative/positive work was 48.5 kgm. Eight subjects developed either spontaneous or provoked facial pain subsequent to the exercise. No positive correlations were demonstrated between the total number of facial pain sites and the amounts of work and power of the muscles, nor between the number of pain sites and the speed of mandibular movement. It is suggested that the appearance of facial pain was associated with the pre-experimental strength and conditioning of the jaw muscles.