The Influence of Posture on Pelvic Floor Muscle Activation and Sensory Awareness in Women With and Without Stress Urinary Incontinence

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Auchincloss, Cindy C.
Pelvic floour muscles , Stress urinary incontinence , Electromyography , Lumbopelvic posture , PFM sensory awareness , Hip position , Rehabilitation Science
The integration of the sensory and motor systems is essential to optimal motor control. Despite the importance of the pelvic floor muscles (PFMs) to continence control and the successful use of PFM training to improve continence function, the sensory awareness of the PFMs has not been evaluated. The aims of this dissertation were to evaluate neuromuscular activation and sensory awareness of the PFMs in women with and without stress urinary incontinence and to examine the potential for position changes to alter sensorimotor function. Three studies were conducted from a single sample comprising continent women and women with mild and moderate stress urinary incontinence (SUI), as determined through a validated questionnaire. PFM electromyographic (EMG) signals were recorded at rest and during PFM maximum voluntary contractions (MVCs) performed in different positions and postures. During each MVC, participants rated their awareness of their PFMs contracting using a visual analog scale (VAS). Sensorimotor function was compared among the groups and among positions within each group. The relationship between PFM activation and sensory awareness of activation was determined using correlation analyses. Overall, sensorimotor function of the PFMs was lower in women with SUI. The group of women with moderate SUI generated the lowest amplitudes of PFM activity during MVCs and was the only group with lower maximal activation recorded in standing compared to lying. Changing positions influenced PFM activation and awareness, although the impact of position was inconsistent among the positions and groups. Those with SUI rated their sensory awareness lower than continent women; women with mild symptoms reported the lowest awareness. Further, when lying down, sensory awareness was not associated with PFM performance in women with SUI, and when standing the relationship between PFM activation and awareness was poor for all women. These findings suggest that PFM awareness may be compromised in women with SUI and neuromuscular activation is impaired among women with moderate SUI symptoms but not mild symptoms. What women report that they “feel” when their PFMs are contracting, may not reflect what the PFMs are doing. The results of this research suggest that verification of a correct PFM contraction is necessary when training the PFMs.
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