Effects of pelvic floor muscle training on strength and predictors of response in the treatment of urinary incontinence

Aims: The objectives of this study were (1) to determine the effect of training on pelvic floor muscle strength; (2) to determine whether changes in pelvic floor muscle strength correlate with changes in continence; and (3) to determine whether demographic characteristics, clinical incontinence severity indices, or urodynamic measures predict response to pelvic floor muscle training. Methods: One hundred thirty-four women with urinary incontinence (95 = genuine stress incontinence [GSI]; 19 = detrusor instability [DI]; 20 = mixed incontinence [GSI + DI]) were randomized to pelvic floor muscle training (n = 67) or bladder training (n = 67). Urinary diaries, urodynamic evaluation, and vaginal pressure measurements by using balloon manometry were performed at baseline and after 12 weeks of therapy. Primary outcome measures consisted of incontinent episodes per week and vaginal pressure measurements. Results: Both treatment groups had a reduction in incontinent episodes (P ≤ 0.004). Vaginal pressures increased more with pelvic floor muscle training than with bladder training (P = 0.0003). Other than a weak correlation between a reduction in incontinent episodes/week and an increase in maximum sustained vaginal pressure in women with GSI (r = 0.32, P = 0.04), there were no significant correlations between increases in pelvic floor muscle strength and improvement in continence status. There were no significant correlations between baseline demographic characteristics, clinical incontinence severity, or urodynamic measures and increases in vaginal pressure or improvement in clinical severity after pelvic floor muscle training. Conclusions: Pelvic floor muscle training improves continence and increases vaginal pressure measurements, but the direct correlations between these alterations are weak. A woman's response to behavioral treatment does not depend on her demographic characteristics, clinical incontinence severity, urodynamic measures, or initial pelvic floor muscle strength.