Comparison of active and passive forces of the pelvic floor muscles in women with and without stress urinary incontinence.

BACKGROUND The reduction of the pelvic floor muscles (PFM) strength is a major cause of stress urinary incontinence (SUI). OBJECTIVES To compare active and passive forces, and vaginal cavity aperture in continent and stress urinary incontinent women. METHOD The study included a total of thirty-two women, sixteen continent women (group 1--G1) and sixteen women with SUI (group 2--G2). To evaluate PFM passive and active forces in anteroposterior (sagittal plane) and left-right directions (frontal plane) a stainless steel specular dynamometer was used. RESULTS The anteroposterior active strength for the continent women (mean±standard deviation) (0.3±0.2 N) was greater compared to the values found in the evaluation of incontinent women (0.1±0.1 N). The left-right active strength (G1=0.43±0.1 N; G2=0.40±0.1 N), the passive force (G1=1.1±0.2 N; G2=1.1±0.3 N) and the vaginal cavity aperture (G1=21±3 mm; G2=24±4 mm) did not differ between groups 1 and 2. CONCLUSION The function evaluation of PFM showed that women with SUI had a lower anteroposterior active strength compared to continent women.