Abstract
Pelvic floor muscle (PFM) training is the first-line treatment for women of all ages with urinary incontinence (UI), but evidence supporting its effects on the functional anatomy of the pelvic floor is scarce in older women. We aimed to evaluate the long-term (one-year) effects of PFM training on the shape of the levator hiatus (LH) in older women with UI and its association with PFM force, incontinence severity, and potential effect modifiers (age, UI severity, BMI, and UI type). This is a secondary analysis of the GROUP study, a non-inferiority RCT assessing the effects of a structured and progressive 12-week PFM training program to treat UI in older women. Data were available from 264/308 participants at the one-year follow-up. PFM training resulted in reduced LH size toward a more "circular" shape, which was consistently associated with greater PFM force and reduced UI severity. Further, no significant interactions were found between LH shape changes and any of the potential effect modifiers, suggesting that women will potentially benefit from PFM training, regardless of age, UI severity, BMI, and UI type (stress or mixed), with changes that can be observed in the functional anatomy of the pelvic floor and sustained in the long-term.