Postural response of the pelvic floor and abdominal muscles in women with and without incontinence

Authors

  • Michelle D. Smith,

    1. Division of Physiotherapy, School of Health and Rehabilitation Sciences, The University of Queensland, St. Lucia, Queensland 4072, Australia
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  • Michel W. Coppieters,

    1. Division of Physiotherapy, School of Health and Rehabilitation Sciences, The University of Queensland, St. Lucia, Queensland 4072, Australia
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  • Paul W. Hodges

    Corresponding author
    1. Division of Physiotherapy, School of Health and Rehabilitation Sciences, The University of Queensland, St. Lucia, Queensland 4072, Australia
    • Division of Physiotherapy, The University of Queensland, St. Lucia, Qld 4072, Australia.
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  • No conflict of interest reported by the author(s).

Abstract

Aims

To determine whether activity of the pelvic floor (PF) and abdominal muscles differs between continent and incontinent women in response to a postural perturbation with a moderately full or empty bladder.

Methods

Electromyographic (EMG) activity of the PF and abdominal muscles was recorded with surface electrodes prior to and after a postural perturbation in which a 1 kg weight was dropped 30 cm into a bucket held by the subject. Perturbations were applied to the trunk in trials in which the timing of the weight drop was unknown (unexpected) or predictable (expected). Trials were performed with the bladder empty, and when the subject reported a sensation of moderate bladder fullness after drinking between 200 and 1,000 ml of water.

Results

Women with incontinence demonstrated increased PF EMG compared to continent women both prior to and during the postural response associated with unexpected loading. In addition, obliquus externus abdominis EMG was increased in incontinent women during these trials. When the bladder was moderately full, PF EMG decreased, whereas abdominal muscle EMG tended to increase.

Conclusions

These data suggest that women with incontinence have increased PF and abdominal muscle activity associated with postural perturbations. This finding challenges the clinical assumption that incontinence is associated with reduced PF muscle activity, and suggests that training control and coordination of abdominal muscle activity may be important in treatment of this condition. The contrasting effects of increased bladder volume on PF and abdominal muscle EMG are likely to present further challenges to the maintenance of continence. Neurourol. Urodynam. 26:377–385, 2007. © 2007 Wiley-Liss, Inc.

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