Do posture and straining influence urinary-flow parameters in normal women?

The influence of posture of the pelvis and straining on urinary flow was investigated in 21 normal women, mainly physiotherapists, who were asked to urinate on an uro-flow chair at their usual time and frequency. Subjects were at random instructed to urinate in five different test situations: anteversion, anteversion with straining, retroversion, retroversion with straining, and forward bending without straining. The urinary-flow parameters investigated were volume, peak flow, time to peak, peak-to-end time, total time, and mean flow. The analysis was done by means of analysis of variance but only for micturition volumes >150 mL. The morphology of the urinary-flow curves was examined for the presence of irregularities and increasing (after top) or decreasing (for top) curve tops and after-dribbling. Results demonstrated no significant differences for peak flow, total time, and mean flow in the anteversion, retroversion, and the forward-bending position. This holds for test situations and re-test controls. However, straining increased the peak flow and mean flow rates in all positions and in all women, whereas it reduced the total voiding time. The voided volumes were lowest in anteversion. Irregularities were less frequent in the forward-bending position. It can be concluded that the forward-bending position is the most preferable urinating position to relax the pelvic floor muscles. Neurourol. Urodynam. 19:3-8, 2000.