Temporal trends in trunk flexor endurance and intra-abdominal pressure in postpartum women.

Abstract

Objectives: To describe change in trunk flexor endurance and intra-abdominal pressure (IAP) associated with trunk flexor assessment and explore factors associated with change in trunk flexor endurance during the first postpartum year.Design: Ancillary analysis of an ongoing prospective cohort study.Methods: Participants (N\xa0=\xa0282) were primiparous women delivered vaginally. They completed trunk flexor endurance testing while assessing IAP, body habitus measures (body mass index, waist circumference, and body composition), and questionnaires 5-10\xa0weeks and 11-15\xa0months postpartum. We investigated change in trunk flexor endurance by quartile of improvement and factors associated with improvement (Q4 vs. Q1-Q3) using multivariable models, adjusted for baseline endurance.Results: Mean age was 28\xa0±\xa05\xa0years. The median (IQR) trunk flexor hold time increased from early to late postpartum (129/IQR\xa0=\xa068, 217 vs 148/IQR\xa0=\xa080, 265\xa0seconds, p =\xa0.01) and mean (SD) IAP decreased (55/SD\xa0=\xa013 vs 48/SD\xa0=\xa014\xa0cmH20, p <\xa0.0001). The most improved group (Q4) increased endurance time by 176\xa0seconds (95% CI\xa0=\xa0103, 254), were less likely to be Hispanic, more likely to be older, more educated, and have lower measures of body habitus than women in Q1-Q3. Conclusion: Trunk flexor endurance increased and IAP decreased over one year postpartum. Lower body habitus and higher age early postpartum predicted greatest improvement in trunk flexor endurance at 1 year.