Lack of both sex differences and influence of resting blood pressure on muscle pain intensity.

OBJECTIVE

To test whether muscle pain intensity caused by different intensities of unaccustomed eccentric exercise was moderately and negatively associated with resting blood pressure, and whether women reported higher pain ratings compared with men in response to such exercise.

DESIGN AND SUBJECTS: The repeated measures design involved random assignment of 42 young adults (21 women, 7 per condition) to complete elbow extension exercises with a weight that was 80%, 100%, or 120% of their maximal voluntary concentric strength. Total work was equated by manipulating the number of repetitions performed in the 80% (n = 45), 100% (n = 36), and 120% (n = 30) condition groups.

SETTING

A clinical laboratory in a large university in the southeastern U.S.

OUTCOME MEASURES: Pain intensity ratings averaged over 3 days and resting blood pressure measurements averaged over 6 days.

RESULTS

For both sexes there was a dose-response relation between the relative intensity of the unaccustomed eccentric exercise and mean pain intensity ratings. Mean pain intensity was not significantly related to systolic or diastolic blood pressure. There was no significant sex difference in pain intensity, although men's ratings, in contrast to expectations, tended to be higher than the women's ratings.

CONCLUSIONS

The negative findings, contrary to those predicted from previous experiments in which other types of noxious stimuli have been used, suggest that sex and blood pressure associations with pain intensity are stimulus dependent.