The state of pelvic floor muscle dynamometry: A scoping review

At What Point in the Menstrual Cycle Are the Pelvic Floor Muscles at Their Weakest?

Pelvic floor muscle (PFM) strength is a critical factor for optimal pelvic floor function. Fluctuations in strength values based on different phases of the menstrual cycle (MC) could signify a need for a paradigm shift in evaluating, approaching, and planning training. This research aims to examine and contrast the pelvic floor muscle strength during different phases of the menstrual cycle. A prospective observational study employing digital assessment with the modified Oxford scale and vaginal dynamometry measurements was performed, in order to assess the baseline strength and the contraction strength of the PFMs in eumenorrheic females at three different phases of the MC: the early follicular phase (EFP), the late follicular phase (LFP), and the mid-luteal phase (MLP). During two complete cycles, tympanic temperature and body weight were measured and the urinary luteinizing hormone concentration was tested to determine the time of ovulation. In total, 216 dynamometric measurements of PFM strength were obtained from eighteen nulliparous women (25.72 ± 5.03 years). There were no differences between the baseline strength (p = 0.886) and the contraction strength (p = 0.756) with the dynamometric speculum. In the post hoc analysis, the baseline strength, contraction strength, and strength showed no significant differences between MC phases. As no differences in PFM strength in women were found, the PFMs do not seem to be weaker at any time during the menstrual cycle. It appears that the assessment, establishment, and monitoring of a PFM training program could be initiated at any point in the cycle.

Is the Elite Female Athlete's Pelvic Floor Stronger?

Background: Exercise can stress the pelvic floor muscles (PFMs). This study sought to assess the strength of the PFMs according to the level of physical exercise. Methods: An analytical observational study was carried out using digital palpation and dynamometry measurements to assess PF strength. Healthy nulliparous women were stratified according to physical exercise (physically active and sedentary) and level of physical exercise (elite, amateur, and sedentary). Results: Fifty-four women were analyzed, with a mean age of 25.64 (5.33) years and a BMI of 21.41 (2.96) kg/m2. Differences in the passive force and strength were observed between both groups of women (p < 0.05), and the strength was around two times higher in physically active women (p < 0.05). The strength was similar between elite female athletes and sedentary women (p > 0.05), but statistical differences were found with amateurs (p < 0.05). The PFM strength (p = 0.019) of elite female athletes (0.34 N) was almost half that of amateurs (0.63 N) and twice as strong as that of sedentary women (0.20 N). However, these differences were not significant using digital palpation (p = 0.398). Conclusions: Women who exercise generally have greater PFM strength than women who do not exercise. Physical exercise could strengthen the PFM; however, the high intensity demanded by high-level sports does not seem to proportionally increase the strength of the PFMs.

The acute effects of running on pelvic floor morphology and function in runners with and without running-induced stress urinary incontinence

INTRODUCTION AND HYPOTHESIS

The aim of this study was to examine the impact of a single running session on pelvic floor morphology and function in female runners, and to compare those with and without running-induced stress urinary incontinence (RI-SUI).

METHODS

This cross-sectional, observational study involved two groups: female runners who regularly experienced RI-SUI (n = 19) and runners who did not (n = 20). Pelvic floor muscle (PFM) properties were assessed using intravaginal dynamometry during maximal voluntary contractions (MVC) and during passive tissue elongation. The morphology of the pelvic floor was assessed at rest, during MVC and during maximal Valsalva maneuver (MVM) using 2D and 3D transperineal ultrasound imaging before and after a running protocol. Mixed-effects ANOVA models were used to compare all outcomes between groups and within-groups, including the interaction between group and time. Effect sizes were calculated.

RESULTS

No changes in PFM function assessed using intravaginal dynamometry were observed in either group after the run. Significant and large within-group differences were observed on ultrasound imaging. Specifically, the area and antero-posterior diameter of the levator hiatus were larger after the run, the bladder neck height was lower after the run, and the levator plate length was longer after the run (p ≤ 0.05). At the peak MVM and MVC, the bladder neck height was lower after the run than before the run (p ≤ 0.05). No between-group differences were observed for any outcomes.

CONCLUSIONS

Running appears to cause transient strain of the passive tissues of the female pelvic floor in runners both with and without RI-SUI, whereas no concurrent changes are observed in PFM contractile function.