The impact of acute and chronic strenuous exercise on pelvic floor muscle strength and support in nulliparous healthy women

Abstract

Strenuous physical activity, which is known to increase intraabdominal pressure and theoretically places stress on the pelvic floor, may affect pelvic support in nulliparous women. The aims of this study were to: (1) examine the differences in maximal vaginal descent (MVD), vaginal resting pressure (VRP), and pelvic floor muscle strength (PFMS) between women who habitually perform strenuous exercise vs women who refrain from performing strenuous exercise; and (2) compare MVD, VRP, and PFMS before and immediately following physical activity in the strenuous and nonstrenuous groups separately. Participants were healthy nulliparous women ages 18-35 years who were habitual strenuous or nonstrenuous exercisers. Women in the strenuous group participated in CrossFit (CrossFit, Inc., Washington, DC) at least 3 days per week for at least 6 months. We assessed anthropometric and body composition values using standardized procedures. Participants completed the Pelvic Organ Prolapse Quantification examination and pelvic muscle strength assessment before and again within 15 minutes of completing exercise (CrossFit for the strenuous group and self-paced walking for the nonstrenuous). A research nurse masked to study group assignment recorded MVD, defined as the greatest value of anterior, posterior, or apical support, and VRP and PFMS using a perineometer. Maximal PFMS was recorded as the highest pressure measured in 3 vaginal contraction trials. Data were analyzed using parametric and nonparametric tests as appropriate. P < .05 was considered significant. Seventy nulliparous women participated in the study, 35 in each group. The mean age was 24.77 ± 4.3 years. Compared to the nonstrenuous group, strenuous participants were heavier (64.70 ± 7.78 kg vs 60.6 ± 8.99 kg, P= .027), had lower percent body fat (23.36 ± 5.88% vs 27.55 ± 7.07%, P= .003), and had higher handgrip strength (20.78 ± 5.97 kg vs 16.04 ± 11.04 kg, P= .001). Before exercise, there were no significant differences in VRP (P= .167), MVD (P= .49), or maximal PFMS (P= .773) between the strenuous and nonstrenuous groups. Immediately following exercise, we observed significant increases in MVD in both the strenuous (P= .008) and nonstrenuous (P= .025) groups, indicating marginal decreases in support. VRP significantly decreased in both groups after exercise. Maximal PFMS did not change significantly in either group after exercise. After an exercise bout typical for each group, vaginal support and VRP decreased slightly in both groups. Based on preexercise measures, chronic strenuous exercise demonstrated neither beneficial nor deleterious effects on pelvic floor strength or support. While strenuous women had greater grip strength than nonstrenuous women, PFMS was not significantly greater, suggesting that targeted pelvic floor muscle strengthening, rather than general muscle fitness, is needed to maximize PFMS.