Association between isokinetic abdominal muscle strength, pelvic floor muscle strength and stress urinary incontinence severity

Objectives Studies have shown that there is co-activation between abdominal and pelvic floor muscles (PFM) in physiological conditions. This study aimed to assess pelvic floor and isokinetic trunk flexors function in non-active incontinent women, and to investigate the association between the strength of these muscle groups and the severity of stress urinary incontinence (SUI). Methods A cross-sectional study was carried out. Twenty-five incontinent women were enrolled after one-hour pad test results and compared to twenty asymptomatic women. The severity of SUI was determined by the Pad test and Urinary Distress Inventory, Short Form (UDI-6). PFM function was assessed using the modified Oxford Scale, intra-vaginal PFM electromyography, and PFM endurance according to the PERFECT scheme. Trunk flexors strength was assessed using a Cybex Norm II dynamometer. Results Incontinent women had a weaker PFM and isokinetic abdominal muscle strength compared to continent women (P<0,05). SUI severity was negatively correlated with PFM strength (r=–0,620, P=0,001), isokinetic trunk flexors strength (r=–0,605, P=0,001), and PFM endurance (r=–0,561, P=0,003) in incontinent women. A positive correlation between PFM function and isokinetic trunk flexors strength was found in incontinent women (r=0,488, P=0,013). Conclusion Non-active incontinent women had weaker pelvic floor muscles and isokinetic trunk flexors strength compared to continent ones. The positive correlation found between these two muscle groups may be explained by their synergic activity. These findings suggest that the severity of SUI could be related not only to PFM strength but also to abdominal muscle weakness. Further research is needed to recommend abdominal wall training as an alternative method to treat SUI. Level of proof 3.