Ultrasound assessment of the abdominal, diaphragm, and pelvic floor muscles during the respiratory and postural tasks in women with and without postpartum lumbopelvic pain: a case-control study.

Introduction And Hypothesis: Postpartum lumbopelvic pain (PLPP) is common among women. Abdominal, diaphragm, and pelvic floor muscles (PFMs) modulate intraabdominal pressure as a part of the force closure mechanism. These muscles are exposed to changes during pregnancy that compromise the force closure mechanism. It was hypothesized that abdominal and PFMs activity, the direction of bladder base displacement, diaphragm thickness, and excursion might differ between women with and without PLPP during respiratory and postural tasks.

Methods: Thirty women with and 30 women without PLPP participated in this case-control study. Ultrasound imaging was used to assess the abdominal, diaphragm, and PFMs during rest, active straight leg raising (ASLR) with and without a pelvic belt, and deep respiration.

Results: The bladder base descent was significantly greater in the PLPP group than in the controls during deep respiration and ASLR without a belt (p = 0.026; Chi-squared = 6.40). No significant differences were observed between the groups in the abdominal muscles activity and diaphragm muscle thickness. There was a significant interaction effect of the group and the task for diaphragm excursion (F (2, 116) = 6.08; p = 0.00) and PFM activity (F (2, 116) = 5.22; p = 0.00). In the PLPP group, wearing a belt compromised altered PFM activation and direction of bladder base displacement.

Conclusion: The PFM activity, direction of bladder base displacement, and diaphragm excursion differed between groups during postural and respiratory tasks. Therefore, it is recommended to involve retraining of the PFMs and diaphragm muscle in the rehabilitation of women with PLPP.