The Physical Implications of Diastasis Recti Abdominis Among Women at the End of Their First Postpartum Year
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A separation of the abdominal muscles at the linea alba, diastasis recti abdominis (DRA), appears to persist beyond the first postpartum year in a substantial proportion of women. Although tissue strain at the linea alba should theoretically cause difficulties during tasks that require load transfer across the midline, there is limited evidence to support that DRA impairs trunk muscle function. Four studies are presented in this dissertation, in which we aimed to investigate the impact of DRA on women’s health. The first two studies established the reliability and validity of two key outcome measures. A custom isometric trunk dynamometer (IFLEXD) was validated against the Biodex 3TM dynamometer. Torque values from the two systems were found to be strongly correlated. The between-day reliability for outcomes derived from the IFLEXD were excellent. In the next study we investigated whether the angle at which an ultrasound transducer is held influences measurements of inter-rectus distance (IRD). Transducer angle did not appear to impact IRD measured in parous women. The latter two studies investigated the impact of DRA on trunk symptoms and function. In the third study we explored whether women with and without DRA at one-year postpartum demonstrated differences in their maximal trunk flexion, extension, and rotation torque generating capacity, trunk flexion, extension, and lateral flexion endurance, ability to perform a sit-up and the Sitting-Rising Test, and/or self-reported pain and dysfunction. The results suggest that women who present with DRA at one-year postpartum have reduced maximal trunk rotation torque generating capacity and perform more poorly on a sit-up test. Women with DRA did not report higher levels of lumbopelvic pain or dysfunction. In the final study, we investigated whether a recently proposed measurement of DRA severity, the distortion index (DI) predicted impairment and dysfunction associated with DRA more strongly than IRD. DI and IRD were highly correlated, and, as such, DI was associated with women’s ability to generate trunk rotation torque and to perform a sit-up. Yet, our sample of women with mild DRA, relative to IRD, DI did not appear to contribute to our understanding of the functional impacts of DRA.