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Avni C.1, Jones R.2, Hanekom S.1
1Stellenbosch University, Health Sciences, Cape Town, South Africa, 2Southampton University, Southampton, United Kingdom
Background: The pelvic floor muscles (PFMs) are well researched with respect to their control of visceral function (bladder, bowel and sexual function). PFM activity is effected by weightbearing, although most research has been conducted in non-weightbearing positions for subject comfort and investigator convenience. Pelvic populations are often symptomatic in weightbearing with dynamic activities.
Purpose: The aim of this study was to describe the electromyographic (EMG) activity of the PFMs in healthy nulliparous female adults during the various weightbearing phases of the gait cycle. In order to fulfill the aim, certain objectives needed to be met. The primary objectives included reporting on subject characteristics; describing a base level of PFM EMG activity in standing; describing PFM EMG activity during gait; and establishing the support status with respect to time and its impact on PFM EMG activity. Secondary objectives were describing PFM EMG activity at rest (baseline), during MVC and sub-max in standing in order to establish a base level.
Methods: This was a descriptive observational study at the Motion Analysis Laboratory Stellenbosch University, including nine healthy nulliparous female volunteers to characterize PFM EMG during gait. The primary study included paperwork (consent and a questionnaire to confirm eligibility), set up (empty bladder, barefoot, height and weight measurements, 3D analysis heel toe makers, wireless adapter, electrode self insertion), test (base level and walking six times the length of the data capture area) and final aspects (electrode self-removal and feedback). A primary investigator performed the testing, with assistance from the motion analysis laboratory engineer and technician. We used four varibales of 3D motion analysis and five variables of PFM EMG to describe a base level in standing, and involuntary PFM activity with respect to the various weightbearing phases of the gait cycle.
Results: There was one trial with corrupt data, leaving eight subjects for analysis (age 33,5 ± 8,52 years; BMI 23,98 ± 5,06 kg/m2). A distinct wave pattern of involuntary PFM activity emerged during gait. Older subjects used a lower %MVC than younger subjects, from as low as 20%MVC to over 100%MVC. There was greater inter than intra subject variability. Pelvic floor muscle EMG decreased during double support, which showed less intra limb loading variation than single support, but greater inter limb loading differences. During single support PFM EMG tended to flatten out, then increase to a peak, before decreasing into double support.
Conclusion(s): PFM activity during gait presented as a characteristic wave, despite inter subject variations. This wave suggests involuntary activity of the PFMs based on weightbearing, with differential intra and inter limb loading strategies. Potential cross talk, and the representation of the PFMs as a single unit should limit the interpretation of these results. Further research should establish ranges of PFM acitivty during gait in different populations e.g. male vs. parous female vs. pelvic girlde pain populations.
Implications: Involuntary activity of the PFMs exists during gait, and appears to be related to weightbearing. The function of the PFMs during gait needs to be established, so as to provide focused treatment for pelvic populations.
Funding acknowledgements: South African Society of Physiotherapy R2000 (PPK fund)
Patterson Medical for sponsoring the Periform electrodes
Patterson Medical for sponsoring the Periform electrodes
Topic: Women's & mens pelvic health
Ethics approval: Stellenbosch University Health Research Ethics Committee approved the study (S15/08/170)
All authors, affiliations and abstracts have been published as submitted.
