This study aimed to investigate the association between transversus abdominis (TrA) muscle activation, urinary incontinence severity, and pelvic floor symptoms in older women with stress urinary incontinence. Given the synergistic role of TrA with pelvic floor muscles in continence mechanisms, understanding this association may contribute to improved clinical assessment and rehabilitation strategies.

Twenty-two women aged 60–75 years with stress urinary incontinence were included in this pilot study (age: 66.77 ± 6.56 years; BMI: 30.02 ± 5.34 kg/m²). Urinary incontinence severity was assessed using the Incontinence Severity Index (ISI), and pelvic floor symptoms were evaluated using the Pelvic Floor Distress Inventory (PFDI-20), including its subdomains: Pelvic Organ Prolapse Distress Inventory (POPDI), Colorectal-Anal Distress Inventory (CRADI), and Urinary Distress Inventory (UDI). TrA muscle activation was measured using surface electromyography (sEMG) with the NeuroTrac MyoPlus 4 Pro (Verity Medical Ltd.). Self-adhesive surface electrodes were placed over the TrA region according to standard sEMG guidelines. All participants were assessed in a standardized position to ensure measurement consistency. sEMG recordings were obtained during voluntary contraction tasks. Muscle activation parameters, including work average (μV) and peak activation (μV), were recorded and analyzed. The associations between TrA muscle activation parameters, urinary incontinence severity, and pelvic floor symptoms were analyzed using Spearman correlation analysis. Ethical approval was obtained from the relevant institutional ethics committee prior to the study.

Work average activation of TrA muscle showed no significant correlation with ISI score (rho = -0.233, p = 0.297), POPDI (rho = -0.069, p = 0.760), CRADI (rho = -0.092, p = 0.684), UDI (rho = -0.203, p = 0.364), or PFDI total score (rho = -0.117, p = 0.605). Similarly, peak activation of TrA muscle showed no significant correlation with ISI score (rho = -0.260, p = 0.242), POPDI (rho = -0.081, p = 0.721), CRADI (rho = -0.010, p = 0.966), UDI (rho = -0.062, p = 0.785), or PFDI total score (rho = -0.040, p = 0.859). Although all correlations were negative in direction, none reached statistical significance (Table 1).

As a result of this study, all correlation coefficients were found to be negative, suggesting that increased TrA muscle activation may be associated with lower urinary incontinence severity and reduced pelvic floor symptom burden in older women with stress urinary incontinence. However, since none of these associations reached statistical significance. These findings indicate that stress urinary incontinence is a multifactorial condition and that factors such as pelvic floor muscle function, neuromuscular coordination, and other biomechanical components may play a more substantial role. Further studies with larger sample sizes and more comprehensive assessment methods are warranted to clarify the relationship between TrA activation and pelvic floor dysfunction.

The present study is noteworthy in that it evaluates TrA muscle activation not only as an indicator of muscle function, but also in relation to urinary incontinence severity and pelvic floor symptom burden in older women with stress urinary incontinence. In addition, the separate analysis of the PFDI subdomains provides a more detailed clinical perspective and contributes meaningful evidence to the existing literature.