Characterisation of Pelvic Floor Muscle Activation in Adults With Intellectual Disability Using Surface Electromyography: A Comparative Cross-Sectional Study.

INTRODUCTION: Adults with intellectual disability (ID) have high rates of urinary incontinence, yet objective neuromuscular data are limited. We compared pelvic floor muscle (PFM) activation using surface electromyography (sEMG) in adults with ID versus matched controls. METHODS: In this cross-sectional study, 104 participants were recruited to an ID group (n = 52) and a matched control group (n = 52). Perianal sEMG recorded five maximal voluntary contractions following a standardised protocol. Intensity, variability, contraction onset and relaxation times were analysed using t or Mann-Whitney tests, MANOVA and multiple regression. RESULTS: Compared with controls, the ID group showed lower mean activity (5.3 ± 6.0 vs. 8.8 ± 7.2 μV; p < 0.001; d = 0.52), lower peaks, longer onset and greater variability; relaxation parameters did not differ. MANOVA indicated a significant global group effect (Wilks' λ = 0.801, p = 0.003). Regression identified ID as the sole independent predictor of reduced activation. CONCLUSIONS: Adults with ID exhibit weaker, less stable and delayed PFM activation, supporting tailored physiotherapy.