Pelvic floor muscle reflex activity during drop-landings and mini-trampolining - an exploratory study
IUGA Academy. Luginbuehl H. Jun 30, 2018; 212802; 360 Topic: Stress Incontinence
Helena Luginbuehl
Helena Luginbuehl

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Pelvic floor muscle reflex activity during drop-landings and mini-trampolining – an exploratory study

Wassmer Saeuberli, P1; Schraknepper, A2; Eichelberger, P2;Luginbuehl, H2; Radlinger, L2

1: Zurich University of Applied Sciences, School of Health Professions, Institute of Physiotherapie, Winterthur, Switzerland and Cantonal Hospital Baden AG, Baden, Section Physiotherapy, Switzerland; 2: Bern University of Applied Sciences, Department of Health Professions, Division of Physiotherapy, Bern, Switzerland

Introduction: Impact activities like jumps can provoke symptoms of stress urinary incontinence (SUI) even in young female athletes (1). Women practicing high-impact sports, where both feet leave the ground, show a higher SUI prevalence than those practicing low-impact sports (2). To date, hardly any studies are available testing pelvic floor muscle (PFM) activity during high impact sports activities.

Objective: The aim of this study was to investigate and to describe PMF activity in young and healthy women during drop-landings and mini-trampolining.

Methods: An exploratory cross-sectional pilot study with experimental measurements was conducted to gain knowledge about involuntary reflex activity of the PFM during jumps. PFM surface electromyography (EMG) was measured in 16 healthy women (age 26.8 ± 5.2 years, body mass index 22.3 ± 2.4 kg/m2) with a vaginal probe during five drop-landings from 0.15, 0.30 and 0.45 m height as well as during 20 seconds mini-trampolining with 75 and 90 jumps per minute, which led to higher and lower jumps height respectively. Root mean square values of the EMG signals were analyzed from 30 ms before to 150 ms after foot strike and were divided into six time intervals of 30 ms. The peak activity during maximum voluntary contraction (MVC) was used for EMG normalization (= 100 %MVC). Activity-onset threshold was determined as the mean of rest activity plus 2 standard deviations. Statistical analyses were performed with Wilcoxon and Friedman tests. The study was approved by the local Ethics Committee.

Results: EMG activity during drop landing and mini-trampolining was significantly above PFM onset threshold, pre-activity and reflex activity increased significantly with jumping height (all p < 0.05). During drop-landings, the maximum PFM activity followed between 34 and 44 ms after foot strike and amounted to 115-182 %MVC, whereas during mini-trampolining the maximum PFM activity was reached at 133 ms and amounted to 85-115 %MVC. The vertical ground reaction force (GRF) during the drop-landings took 60 to 65 ms time to peak after foot strike whereas on the mini-trampoline the GRF took 180 to 210 ms to reach the peak.

Conclusions: PFM reflex activity depends on ground reaction forces. As a result of slower increase in GRF during mini-trampolining PFM reflex activity is lower and delayed in time compared to drop-landings. Further studies should firstly investigate the PFM reflex activity of patients suffering from SUI and secondly the responsiveness of the PFM EMG variables of the current study to a physical therapy intervention for SUI patients.

References: (1) Int Urogynecol J 2012;23(12):1687-91; (2) Int J Sports Med 2017 Nov;38(12):937-941


Work supported by industry: no.

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