Leitner M1, Moser H1, Patric E1, Kuhn A2, Radlinger L1
1Bern University of Applied Sciences, Department of Health Professions, Bern, Switzerland, 2Bern University Hospital, Gynaecology, Bern, Switzerland
Background: A prevalence of 41% of stress urinary incontinence (SUI) has been found in female athletes with the highest prevalence in sports involving impact activities. Dynamic measurements of the pelvic floor muscles (PFMs) during whole body movements, such as running, contribute to better understand the pathophysiology of stress urinary incontinence.
Purpose: Analysis of reliability is important in order to get information about the consistency of a measurement and whether a systematic measurement error affected the results. Aspects of intra-session reliability of PFM activity during running in a continent sample have been reported previously. The aim of this study was to determine the intra-session reliability of the temporal and magnitude components of EMG activity during running at three different speeds in continent (CON) and SUI-affected women.
Methods: Fifty women were included in this exploratory cross-sectional study (CON: n=28; SUI: n=22). SUI was diagnosed according to the ICIQ-UIsf questionnaire. Surface EMG activity from the PFMs during running on a treadmill was recorded with a vaginal probe. EMG was measured during 10 steps at speeds of 7, 11 and 15 km/h. Data from 30 ms before to 150 ms after heel-strike were RMS-parameterized to 6 time- intervals of 30 ms. The reference value, set as 100% for EMG normalization, was calculated as the mean of the peak activity during two maximum voluntary contractions (MVC). Descriptive statistics, ICC (2,1), SEM, MD and ANOVA were computed for the EMG of the 6 time-intervals, amplitude (EMGmax) and time point (tEMGmax) of maximum EMG.
Results: All variables demonstrated no systematic error (ANOVA n. s.). Ranges of reliability indices of the seven EMG-variables (%MVC) are presented for CON and SUI and different speeds: (CON, 7 km/h: ICC = .535-.692, SEM = 12.3-22.0, MD = 8.8-15.4), (CON, 11 km/h: ICC = .581-.777, SEM = 16.0-33.9, MD = 9.7-19.3), (CON, 15 km/h: ICC = .699-.864, SEM = 20.3-37.1, MD = 11.9-15.5), (SUI, 7 km/h: ICC = .746-.915, SEM = 18.2-32.7, MD = 9.9-11.1), (SUI, 11 Km/h: ICC = .780-.926, SEM = 18.2-31.5, MD = 7.4-14.6), (SUI, 15 km/h: ICC = .750-.886, SEM = 27.6-47.2, MD = 14.0-20.0). Referring to the time variable (ms), ICCs ranged from .392-.585 in CON and .380-.623 in SUI, SEM ranged from 369.4-441.0 in CON and 507.6-511.9 in SUI and MD from 357.3-387.9 in CON and 389.9-499.5 in SUI.
Conclusion(s): ICC values (relative reliability) of the EMG variables indicate a moderate to good reliability. SEM and MD values (absolute reliability) show moderate reliability. Higher reliability with increasing speeds can be observed and may be interpreted as less variation in running performance with higher speed. Low reliability of time variables may imply that temporal function varies more across the strides.
Implications: Contrary to the low reliability seen in the temporal component of muscle activity, the magnitude components of muscle activity (%MVC) were more reliable. Analysis of reliability showed no systematic error of measurement. Prospective efforts for the evaluation of PFMs EMG should consider inter-session reliability and whether the average of 20-30 steps might yield better reliability indices.
Keywords: Pelvic Floor, Female, Stress Urinary Incontinence
Funding acknowledgements: Bern University of Applied Sciences, Switzerland
Purpose: Analysis of reliability is important in order to get information about the consistency of a measurement and whether a systematic measurement error affected the results. Aspects of intra-session reliability of PFM activity during running in a continent sample have been reported previously. The aim of this study was to determine the intra-session reliability of the temporal and magnitude components of EMG activity during running at three different speeds in continent (CON) and SUI-affected women.
Methods: Fifty women were included in this exploratory cross-sectional study (CON: n=28; SUI: n=22). SUI was diagnosed according to the ICIQ-UIsf questionnaire. Surface EMG activity from the PFMs during running on a treadmill was recorded with a vaginal probe. EMG was measured during 10 steps at speeds of 7, 11 and 15 km/h. Data from 30 ms before to 150 ms after heel-strike were RMS-parameterized to 6 time- intervals of 30 ms. The reference value, set as 100% for EMG normalization, was calculated as the mean of the peak activity during two maximum voluntary contractions (MVC). Descriptive statistics, ICC (2,1), SEM, MD and ANOVA were computed for the EMG of the 6 time-intervals, amplitude (EMGmax) and time point (tEMGmax) of maximum EMG.
Results: All variables demonstrated no systematic error (ANOVA n. s.). Ranges of reliability indices of the seven EMG-variables (%MVC) are presented for CON and SUI and different speeds: (CON, 7 km/h: ICC = .535-.692, SEM = 12.3-22.0, MD = 8.8-15.4), (CON, 11 km/h: ICC = .581-.777, SEM = 16.0-33.9, MD = 9.7-19.3), (CON, 15 km/h: ICC = .699-.864, SEM = 20.3-37.1, MD = 11.9-15.5), (SUI, 7 km/h: ICC = .746-.915, SEM = 18.2-32.7, MD = 9.9-11.1), (SUI, 11 Km/h: ICC = .780-.926, SEM = 18.2-31.5, MD = 7.4-14.6), (SUI, 15 km/h: ICC = .750-.886, SEM = 27.6-47.2, MD = 14.0-20.0). Referring to the time variable (ms), ICCs ranged from .392-.585 in CON and .380-.623 in SUI, SEM ranged from 369.4-441.0 in CON and 507.6-511.9 in SUI and MD from 357.3-387.9 in CON and 389.9-499.5 in SUI.
Conclusion(s): ICC values (relative reliability) of the EMG variables indicate a moderate to good reliability. SEM and MD values (absolute reliability) show moderate reliability. Higher reliability with increasing speeds can be observed and may be interpreted as less variation in running performance with higher speed. Low reliability of time variables may imply that temporal function varies more across the strides.
Implications: Contrary to the low reliability seen in the temporal component of muscle activity, the magnitude components of muscle activity (%MVC) were more reliable. Analysis of reliability showed no systematic error of measurement. Prospective efforts for the evaluation of PFMs EMG should consider inter-session reliability and whether the average of 20-30 steps might yield better reliability indices.
Keywords: Pelvic Floor, Female, Stress Urinary Incontinence
Funding acknowledgements: Bern University of Applied Sciences, Switzerland
Topic: Women's & men's pelvic health; Sport & sports injuries; Human movement analysis
Ethics approval required: Yes
Institution: Bern University of Applied Sciences, Switzerland
Ethics committee: Ethical Committee of the Canton of Bern, Switzerland
Ethics number: No. 391/14
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