The role of lumbopelvic posture in pelvic floor muscle activation in continent women.

This study was undertaken to determine the effect of changing standing lumbopelvic posture on pelvic floor muscle (PFM) activation amplitude and timing and the resultant vaginal manometry values recorded during static and dynamic tasks. Sixteen nulliparous, continent women between the ages of 22 and 41 years performed five tasks (quiet standing, maximal effort cough, Valsalva manoeuvre, maximum voluntary contraction (MVC) of the PFMs, and a load-catching task) in three different standing postures (normal lumbopelvic posture, hyperlordosis and hypolordosis). Electromyographic (EMG) data were recorded from the PFMs bilaterally using a Periform™ vaginal probe coupled to Delsys™ Bagnoli-8 EMG amplifiers. In separate trials, vaginal manometry was obtained using a Peritron™ perineometer. Lumbopelvic angle was recorded simultaneously with EMG and vaginal manometry using an Optotrak™ 3D motion analysis system to ensure that subjects maintained the required posture throughout the three trials of each task. All data were filtered using a moving 100 ms RMS window and peak values were determined for each trial and task. Repeated-measures analyses of variance were performed on the peak PFM EMG, intra-vaginal pressure amplitudes, and lumbopelvic angles as well as activation onset data for the cough and load-catching tasks. There was significantly higher resting PFM activity in all postures in standing as compared to supine, and in the standing position, there was higher resting PFM activity in the hypo-lordotic posture as compared to the normal and hyperlordotic postures. During the MVC, cough, Valsalva, and load-catching tasks, subjects generated significantly more PFM EMG activity when in their habitual posture than when in hyper- or hypo-lordotic postures. Conversely, higher peak vaginal manometry values were generated in the hypo-lordotic posture for all tasks in all cases. These results clearly indicate that changes in lumbopelvic posture influence both the contractility of the PFMs and the amount of vaginal pressure generated during static postures and during dynamic tasks. Lumbopelvic posture does not, however, appear to have a significant effect on the timing of PFM activation during coughing or load-catching tasks.