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Koenig I1,2, Eichelberger P1, Luginbuehl H1, Kuhn A3, Lehmann C4, Taeymans J1,2, Radlinger L1
1Bern University of Applied Sciences, Department of Health Professions, Bern, Switzerland, 2Vrije Universiteit Brussel, Faculty of Physical Education and Physiotherapy, Brussels, Belgium, 3University Hospital and University of Bern, University Clinic of Gynecology, Bern, Switzerland, 4University Hospital Bern, Department of Physiotherapy, Bern, Switzerland
Background: Running causes urinary leakage in women with stress urinary incontinence (SUI). Small and large alpha-motoneurons (α-MN) of pelvic floor muscles (PFM) are recruited to match their contractile muscle properties to the impact of initial contact while running. Wavelet analyses of electromyograms (EMG) allow to extract EMG frequencies among time with fine time resolution. Hence, task specific fiber type recruitment can be estimated with wavelets since small α-MN generate lower frequencies in the signal and large α-MN higher frequencies.
Purpose: The aim of the study was to compare PFM EMG spectral changes of an experimental group perfoming involuntary reflexive PFM training in addition to standard training versus spectral changes of a control group performing standard training alone.
Methods: In this triple-blinded RCT 77 women with SUI were randomly allocated to the control group (CON, n=39) or the experimental group (EXP, n=38). PFM EMG was measured before intervention and after nine personal physiotherapy sessions. PFM EMG was recorded during 10 s at 7, 9 and 11 km/h treadmill running and analyzed with Morse wavelets. The relative distribution of power (%) over six frequency bands (20-200 Hz) was extracted and analyzed within six time intervals of 30 ms, from -30 ms before to 150 ms after initial contact. A two-factorial analysis of variance for repeated measures and a post-hoc t-test were performed to identify power spectra differences pre and post intervention, within and between the two groups. The significance level was set at p ≤ 0.05.
Results: The power spectra of each time interval showed no statistically significant group differences.
Lowest frequency band 20-50 Hz: The time intervals from 30 ms before to 30 ms after initial contact showed significantly less signal power than the intervals from 30-150 ms after initial contact for all running speeds and both groups. Highest frequency bands 140-200 Hz: The time intervals from 30 ms before to 30 ms after initial contact showed significantly more signal power than the time intervals from 30-150 ms after initial contact for all running speeds and both groups.
Conclusion(s): Although the groups did not differ significantly, differences in the α-MN recruitment behavior in the pre- and post-initial contact phase could be identified.
The evaluated specific differences of EMG spectra in the pre-initial and the post-initial contact phase seem to indicate two different muscle activation events. Power spectra shifts towards higher frequency bands in the pre-initial contact phase could indicate a feed-forward anticipation and a muscle tuning for the expected impact of initial contact event in order to maintain continence.
Implications: Urinary leakage while running can cause a reduction in the quality of life of women. Therefore, a deeper insight into continence mechanisms while running is needed. Differences of pre- and post-initial contact activation behavior of PFM during different running speeds as well as spectral changes towards high or low frequencies could be extracted with wavelets. This information sheds light on specific differences of involuntary reflexive activation patterns while running.
Keywords: Wavelet analysis, electromyography, urinary stress incontinence
Funding acknowledgements: Swiss National Science Foundation (SNSF; 320030_153424/1).
Purpose: The aim of the study was to compare PFM EMG spectral changes of an experimental group perfoming involuntary reflexive PFM training in addition to standard training versus spectral changes of a control group performing standard training alone.
Methods: In this triple-blinded RCT 77 women with SUI were randomly allocated to the control group (CON, n=39) or the experimental group (EXP, n=38). PFM EMG was measured before intervention and after nine personal physiotherapy sessions. PFM EMG was recorded during 10 s at 7, 9 and 11 km/h treadmill running and analyzed with Morse wavelets. The relative distribution of power (%) over six frequency bands (20-200 Hz) was extracted and analyzed within six time intervals of 30 ms, from -30 ms before to 150 ms after initial contact. A two-factorial analysis of variance for repeated measures and a post-hoc t-test were performed to identify power spectra differences pre and post intervention, within and between the two groups. The significance level was set at p ≤ 0.05.
Results: The power spectra of each time interval showed no statistically significant group differences.
Lowest frequency band 20-50 Hz: The time intervals from 30 ms before to 30 ms after initial contact showed significantly less signal power than the intervals from 30-150 ms after initial contact for all running speeds and both groups. Highest frequency bands 140-200 Hz: The time intervals from 30 ms before to 30 ms after initial contact showed significantly more signal power than the time intervals from 30-150 ms after initial contact for all running speeds and both groups.
Conclusion(s): Although the groups did not differ significantly, differences in the α-MN recruitment behavior in the pre- and post-initial contact phase could be identified.
The evaluated specific differences of EMG spectra in the pre-initial and the post-initial contact phase seem to indicate two different muscle activation events. Power spectra shifts towards higher frequency bands in the pre-initial contact phase could indicate a feed-forward anticipation and a muscle tuning for the expected impact of initial contact event in order to maintain continence.
Implications: Urinary leakage while running can cause a reduction in the quality of life of women. Therefore, a deeper insight into continence mechanisms while running is needed. Differences of pre- and post-initial contact activation behavior of PFM during different running speeds as well as spectral changes towards high or low frequencies could be extracted with wavelets. This information sheds light on specific differences of involuntary reflexive activation patterns while running.
Keywords: Wavelet analysis, electromyography, urinary stress incontinence
Funding acknowledgements: Swiss National Science Foundation (SNSF; 320030_153424/1).
Topic: Women's & men's pelvic health
Ethics approval required: Yes
Institution: Bern University of Applied Sciences
Ethics committee: Ethics Committee of the Canton of Bern
Ethics number: Reference number 249/14
All authors, affiliations and abstracts have been published as submitted.
