Incontinence happens when the muscles at the base of the abdomen–the pelvic floor muscles–can’t build enough pressure to support the inner organs. The pelvic floor muscles have to work when pressure in the abdominal cavity increases. Otherwise the organs in the abdomen push against the bowels or bladder, which can lead to incontinence.
These authors wondered whether nearby abdominal muscles could help the pelvic muscles do their work. Specifically, the authors wanted to know whether squeezing the abdominals would trigger the pelvic floor muscles, and how strongly. They also wanted to find out whether the pelvic floor muscles tighten in preparation for increases in abdominal pressure.
Six women and one man participated in the study. Five of the women had given birth vaginally. The other woman had never given birth. None of the subjects was incontinent, though two had mild symptoms now and then.
Electrodes were used to measure pelvic and abdominal muscle activity. An electrode probe was inserted into the anus of all participants as a way to monitor pelvic muscle actions. The women also wore this type of electrode inside their vaginas. Two round electrode pads were attached to the sides of the abdominal cavity over the surface of the lateral abdominal muscles. The authors also watched the way the muscles worked by hooking up an ultrasound imaging machine.
Electric readings and ultrasound images were monitored as participants did a series of exercises. While lying down with their hips flexed forward, they tightened their abdominal muscles gently. Then they worked the muscles harder and harder. A second group of exercises included muscle tightening and relaxing for the pelvic floor and abs while standing.
When participants tightened their abs, their pelvic muscles also contracted. And the stronger the abdominal contraction, the stronger the response from the pelvic floor muscles.
Surprisingly, pressure from the pelvic muscles went up before pressure from the abdominals started. This suggests that increased pelvic muscle activity isn’t just an afterthought. The authors think that the pelvic muscles respond first because they anticipate the pressure that will be needed to keep continence.
Results also showed that, for women, pelvic muscle activity during abdominal exercises was the same as the activity that came from working the pelvic muscles themselves. This suggests that, even if women don’t do special exercises to strengthen the pelvic floor, they may get strong pelvic muscles just by staying active and keeping their abs toned.
This is the first study to show that working the abdominal muscles activates the pelvic floor muscles. Doing specific abdominal exercises may strengthen the pelvic muscles and help prevent incontinence. More research is needed to find out whether these types of abdominal exercises can help people who already have problems with incontinence.