The effect of trunk-stabilizing muscle training in women with stress urinary incontinence: A randomized controlled trial

Introduction: There is little evidence regarding the effect of trunk-stabilizing muscle training on the improvement of stress urinary incontinence (SUI) symptoms.Objective: To investigate the effect of trunk-stabilizing muscle training on transabdominal ultrasonography (TAUS) and clinical urological indices, and on the quality of life (QoL) in women with SUI.Design: Randomized controlled trial.Setting: A university hospital.Participants: Forty-six women with SUI, ages 20-55 years, were randomly assigned to an experimental (n = 23) and control group (n = 23).Interventions: The experimental group performed trunk-stabilization exercises according to the Sapsford protocol, whereas the control group performed pelvic floor muscle (PFM) exercises for 8 weeks.Main Outcome Measures: The primary outcome measure was bladder base displacement (BBD), assessed by TAUS during PFM contraction (PFMC), Valsalva, and abdominal curl. The secondary outcome measures were PFM strength, the severity of urinary incontinence (UI), voiding diary, and QoL, assessed by the Modified Oxford Grading System, the severity index, frequency chart, and lower urinary tract symptoms-QoL questionnaire, respectively. All variables were assessed at baseline and after 8 weeks of intervention.Results: The interaction of group and time was not significant for BBD during PFMC (p = .98), Valsalva (p = .28), abdominal curl (p = .34), and secondary variables (p > .05). The main effect of time was significant in both groups for BBD during PFMC, PFM strength, the severity of UI, voiding diary, and QoL (p < .001), with effect size (d) of 0.30, 0.80, 2.05, 1.07, and 1.03 in the control; and 0.49, 0.52, 1.75, 0.66, and 0.88 in the experimental group, respectively. The main effect of the group was not significant for BBD during PFMC (p = .68), Valsalva (p = .22), abdominal curl (p = .53), and secondary variables (p > .05).Conclusions: Trunk-stabilizing muscle training and PFM exercise are equally effective in the improvement of PFM function, UI symptoms, and QoL in women with SUI. Both methods can be used interchangeably by physical therapists.