Impact of Hip Exercise on Pelvic Muscle Strength and Incontinence in Older Women

Objectives: To examine changes in pelvic floor muscle strength from baseline to post-standardized 12-week hip muscle exercises in older women with urinary incontinence (UI). Additionally, impact of hip exercises on UI symptoms were assessed.

Methods: In this prospective cohort study, women ages 65 and older with UI for at least 3 months (scores ≥3 on the 2-item Incontinence Severity Index [ISI]) underwent a standardized 12-week hip muscle exercise program administered by licensed physical therapists (PTs). The exercise program focused on the external hip rotator muscles with progressive resistance training, alternating in-person and phone visits. Exclusion criteria include previous UI treatments (except for behavioral modification and overactive bladder medications), neurogenic bladder, urinary retention, pelvic organ prolapse beyond the hymen, and neuromuscular condition compromising independent mobility. No concurrent treatments were allowed. Primary outcome was peak pelvic floor muscle contraction measured with a perineometer. Hip muscle strength was measured by a hand-held dynamometer. Other secondary outcomes include UI episodes (UIEs) by 3-day bladder diaries, UI-specific symptom distress and impact assessed using validated questionnaires (ISI, Urinary Distress Index [UDI-6], Incontinence Impact Questionnaire [IIQ-7], and Geriatric Self-Efficacy Index for UI). Pre-post intervention assessments were compared via paired t-tests. Statistical significance was set at 0.05.

Results: Of 35 women, 28 (80%) completed the entire 12-week program. At baseline, mean age was 70.3 (95%CI 67.6-72.9), 54% White, BMI 30.6 (95%CI 28.2-32.9), 26% smoking, 66% osteoarthritis, median vaginal deliveries 2 (IQR 1-3), 37% with prior hysterectomy, 23% on vaginal estrogen, 49% having urgency-predominant, 11% stress-predominant, and 40% mixed UI. Baseline UIEs per 3-day diaries were total 7.4 (95%CI 5.5-9.3), urgency 5.0 (95%CI 3.3-6.7), stress 1.6 (95%CI 0.6-2.5), and insensate 0.9 (95%CI 0.3-1.4). Upon completion of the 12-week hip exercise program, participants demonstrated a significant improvement in hip strength, specifically, hip flexion (pre: 110.5±17.8, post: 128.0±18.6, ∆: +17.4±17.6 lb-force, p< 0.001, Table 1) indicating intervention efficacy. Peak pelvic floor muscle contraction (primary outcome) increased significantly (pre: 29.7±17.4, post: 34.2±19.1, ∆: +4.7±20.7 cm/H2O, p=0.045, Table 2). Improvement was also observed in total number of UIEs (pre: 7.4± 5.2, post: 4.9±4.5 ∆: -2.3±4.0, p=0.008), as well as the validated measure scores (ISI, UDI-6, IIQ-7, and Geriatric Self-Efficacy index, all p< 0.01, Table 2). Of the questionnaires, ISI, UDI-6, and Geriatric Self-Efficacy index met the distribution-based (0.5 standard deviation at baseline) minimum important difference criteria.

Conclusions: Completing the 12-week hip exercise program alone led by licensed PTs, older women with UI demonstrated clinically significant improvement not only in pelvic floor muscle strength but also reduction in UI episodes, UI-specific symptom severity and bother. The impact of hip strength and resistance training exercises on improving pelvic floor muscle strength and function as well as potential contribution to the continence mechanism warrants further investigation.