Gender Differences in Pressure Pain Thresholds during Sustained Jaw Muscle Contraction

Abstract

Purpose: To determine whether a fatiguing clench significantly affects the changes in pressure pain threshold (PPT) in men compared to women. Methods:The changes of PPTs from before to after a sustained clench in 12 men and 12 women were obtained. We used a decrease in median frequencies of surface electromyography (EMG) power spectra from the start to the end of the sustained clench as evidence of fatigue. Endurance time for the clench was used as a covariate. Results:The median frequencies decreased after the clench in both the anterior temporalis and masseter muscles, did not differ with the muscle or the gender of the subjects, and none of the interaction terms were significant. The PPTs were lower for women for both muscles, were decreased after the sustained clench, but failed to show the hypothesized gender by time interaction. Conclusions:Our results show that women have lower PPTs than men, but do not respond differently than men to jaw muscle fatigue. 18,19) but no attention was paid to the gender of the subjects.Based on reports where PPT responses of men and women were compared, 13,14) we hypothesized that muscle fatigue produced by a sustained clench and assessed by determining the shift in the median frequency (MF) of the power spectrum [20][21][22] would lead to a greater decrease in PPT in women than in men. Few data are available to support this hypothesis. 13) Therefore, we have replicated and extended this paradigm. In the present study we have taken into account the confounding problem of different endurance times for men and women of the sustained clench. Our aim was to determine whether a sustained clench significantly affects the changes in PPT in men compared to women.

The Effect of Spinal Muscle Fatigue and Psychosocial Factors on Pressure-Pain Threshold in Healthy Adults

“…However, in this previous study, the Sorensen test was held for a standardized duration, and so the muscles may not have been fatigued to failure. Sex differences in the local and systemic hypoalgesic response to fatiguing exercise may depend on testing location as conflicting results across studies suggest that these differences are muscle specific [ 3 , 19 ].…”