Abdominal muscles' thickness and bladder neck position in regular runners and controls: A comparative ultrasonography study

Aim: The aim of the present study was to compare and quantify with transabdominal ultrasound the IRD, the thickness of the external oblique (EO), internal oblique (IO), transversus abdominis (TrA), rectus anterior (RA) and the location of the bladder neck between runners and controls at rest and during response to different exercises. Methods: A total of 38 women, aged 18-45 years, were recruited from a private rehabilitation center specializing in sports health, and divided into two groups: runners (n = 19) and sedentary women (n = 19). Thickness measurements, using suprapubic ultrasongraphy in B-Mode, of the EO, IO, TrA and RA muscles were taken at rest and during active contraction. Location of the bladder neck at rest and during pelvic floor muscle (PFM) contraction was taken with the transducer located suprapubically in M-Mode. Results: There were no significant differences in EO TrA or RA muscle thickness at rest and during muscle contraction between runners and controls. For the IO muscle, significant differences were observed during ASLR, with runners showing greater muscle thickness (p = 0.032). Bladder neck displacement during a voluntary PFM contraction demonstrated statistically larger cranial movement for the runners of mean 0.76 +/- 0.31 cm than mean 0.40 +/- 0.26 cm for the sedentary group (p = 0.001). Conclusions: regular running is associated with increased thickness of the IO during ASLR, and significantly greater cranial bladder neck displacement during PFM contraction.