Evaluation of pelvic floor muscle activity, pulmonary function, respiratory muscle strength, core muscle endurance, and functional capacity in children with lower urinary tract dysfunction.

Introduction: Lower urinary tract dysfunction (LUTD) is a multifactorial condition affecting children, often presenting with voiding difficulties, urgency, and incontinence. While the condition has primarily been evaluated from a urological perspective, growing evidence suggests that pelvic floor dysfunction may also impact posture, respiration, and trunk muscle performance.

Objective: To evaluate pelvic floor muscles (PFMs) activity, pulmonary function, respiratory muscle strength, core muscle endurance and functional capacity in children with LUTD, and to compare these parameters with healthy peers.

Material and methods: This cross-sectional study evaluated 14 children with LUTD and 14 matched controls (ages 6-15). The symptom severity was evaluated via questionnaires. PFMs activity was measured using surface electromyography. Pulmonary function was evaluated with spirometry [(Forced Vital Capacity (FVC), Forced Expiratory Volume in the First Second (FEV₁), FEV₁/FVC, Peak Expiratory Flow (PEF), Forced Expiratory Flow at 25-75 % of FVC (FEF_25-75)], and respiratory muscle strength was measured using maximal inspiratory and expiratory pressures (MIP and MEP). Core muscle endurance was assessed via curl-up, static back endurance, prone plank, and side plank tests. Functional capacity was assessed using the 6-min walk test (6MWT).

Results: Symptom severity was significantly higher in the LUTD group (p < 0.001). They showed reduced PFMs activity during contraction (work average: p = 0.007; mode: p = 0.001; maximal voluntary contraction: p = 0.006) and weaker respiratory muscle strength (MIP: p = 0.001; MEP: p < 0.001). Although FVC and FEV₁ were similar between groups, the LUTD group had lower PEF (p = 0.017) and FEF_25-75 (p = 0.013). Core endurance was significantly reduced in all tests (p < 0.001), with no difference in 6MWT.

Conclusion: Children with LUTD show impaired pelvic floor function, weaker respiratory muscles, and poor core endurance, even without clear functional limitations. This highlights the need for a multidisciplinary approach including core and respiratory training alongside standard urological care.

Clinical trial registration: The study was prospectively registered on October 17, 2024, in the ClinicalTrials.gov database (Identifier: NCT06652178).