Healthy adults can more easily elevate the pelvic floor in standing than in crook-lying: an experimental study

Questions: Are there any differences in the displacement and endurance of an elevating voluntary pelvic floor muscle contraction in standing and in crook-lying? Are there any differences in these variables between males and females in either test position? Design: An experimental study. Participants: Forty-five nulliparous female and 20 male participants aged 23 years (SD 3) with no symptoms of urinary incontinence or low back pain. Intervention: Voluntary pelvic floor muscle contraction was measured in both standing and crook-lying. Outcome measures: Transabdominal ultrasound was used to measure the displacement (mm) and endurance (s) of pelvic floor elevation. Results: Displacement was greater in standing than in crook-lying (mean difference 2.6 mm, 95% CI 1.5 to 3.7). There was no difference between males and females (mean difference 1.3 mm, 95% CI -0.5 to 3.2). Similarly, endurance of pelvic floor elevation was longer in standing than in crook-lying (mean difference 173 s, 95% CI 12.2 to 22.4). Again there was no difference between males and females (mean difference 0.5 s, 95% CI -9.3 to 8.3). Conclusion: Standing was found to be a more effective position for achieving and sustaining an elevation of the pelvic floor compared to crook-lying, regardless of sex, and this should be taken into account when assessing and training pelvic floor muscle contraction.