Pelvic floor muscle activity during fast voluntary contractions in continent and incontinent women
IUGA Academy. Leitner M. Jun 30, 2018; 212803
Topic: Stress Incontinence
Dr. Monika Leitner
Dr. Monika Leitner

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Pelvic floor muscle activity during fast voluntary contractions in continent and incontinent women

Leitner, M1; Moser, H1; Eichelberger, P1; Kuhn, A2; Radlinger, L1

1: University of Applied Sciences Bern, Department of Health Professions, Division of Physiotherapy; 2: Bern University Hospital, Urogynecology, Bern, Switzerland

Introduction: Stress urinary incontinence (SUI), defined as involuntary loss of urine during effort or physical exertion or upon sneezing or coughing [1], has also been attributed to a lower speed of contraction of the pelvic floor muscles (PFM) [2]. Therefore it was suggested that PFM assessment and training should also include fast voluntary contractions (FVCs). For this, women are instructed to ‘contract-relax’ as quickly and strongly as possible [3].
However, up to date, the feasibility of electromyographic measurements (EMG) as well as the parametrization of data and the comparison between continent and incontinent women has not been reported.

Objective: The purpose of the study was to explore FVC regarding the feasibility of EMG-measurements, contraction on-/offset detection, rate of activity and differences between continent (CON) and stress urinary incontinent (SUI) women.

Methods: Fifty women were included in this exploratory cross sectional study (CON: n=28; SUI: n=22) and examined by means of PFM EMG during rest, maximum voluntary contractions (MVC) and five FVCs. On-/offset of muscle activity was determined as mean of rectified rest activity plus 1 standard deviation. Linear regression was calculated for rate of activity from onset to peak, peak to offset and within 200ms after both, onset and peak. Peak activity and time variables related to onset, peak, and offset were calculated. Descriptive statistics, parametric t-tests and nonparametric Mann-Whitney-U-tests were computed for all respective variables.

Results: All 250 FVC measurements were feasible. On-/offsets were evaluable for 234 of 250 FVCs by a computer-based algorithm, 16 on-/offsets had to be determined manually. FVC almost approached MVC activity level just over 500 ms. Groups did not significantly differ during activity increase and its peak, whereas the SUI group showed a slower activity decrease. The regression model fitted well for linear function.

Conclusions: Feasibility of the parametrisation of activity-time-curve was almost perfect and the introduced parametrisation of the activity time curve can be recommended for future investigations. The significant difference observed between the groups interestingly did not refer to activity increase but instead to a prolonged relaxation phase in the SUI group. This prompts to reconsider the interpretation of FVC in PFM testing and training: FVC obviously do not differentiate SUI from CON regarding activity increase but their ability to relax. It also remains unclear whether FVC rather trains PFM relaxation.

Figure 1: Mean pelvic floor muscles activity (%MVC) with its increase and decrease during fast voluntary contractions (FVC) in continent (CON) and incontinent (SUI) women. Thin lines correspond to one standard deviation (SD) of CON and SUI data. ON indicates the onset-threshold between rest activity and FVC as mean of rest activity plus one standard deviation.


  1. Urology, 2003. 61(1): p. 37-49.
  2. Neurourol Urodyn, 2004. 23(7): p. 668-74.
  3. Physiotherapy, 2001. 87(12): p. 631-642.


Work supported by industry: no.

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