Brief Article
Copyright ©2013 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Orthop. Oct 18, 2013; 4(4): 291-298
Published online Oct 18, 2013. doi: 10.5312/wjo.v4.i4.291
Acute effects of stochastic resonance whole body vibration
Achim Elfering, Jasmine Zahno, Jan Taeymans, Angela Blasimann, Lorenz Radlinger
Achim Elfering, Jasmine Zahno, Department of Work and Organizational Psychology, University of Bern, 3000 Bern 9, Switzerland
Jan Taeymans, Angela Blasimann, Lorenz Radlinger, Health, Bern University of Applied Sciences, CH-3008 Bern, Switzerland
Author contributions: Zahno J did the analyses and performed the study; Taeymans J and Blasimann A co-ordinated and provided the collection of data and were also involved in editing the manuscript; Elfering A and Radlinger L designed the study and wrote the manuscript.
Correspondence to: Achim Elfering, PhD, Department of Work and Organizational Psychology, University of Bern, Fabrikstrasse 8, 3012 Bern, Switzerland. achim.elfering@psy.unibe.ch
Telephone: +41-31-6313639 Fax: +41-31-6318212
Received: June 12, 2013
Revised: August 15, 2013
Accepted: September 4, 2013
Published online: October 18, 2013
Processing time: 137 Days and 21.9 Hours
Abstract

AIM: To investigate the acute effects of stochastic resonance whole body vibration (SR-WBV) training to identify possible explanations for preventive effects against musculoskeletal disorders.

METHODS: Twenty-three healthy, female students participated in this quasi-experimental pilot study. Acute physiological and psychological effects of SR-WBV training were examined using electromyography of descending trapezius (TD) muscle, heart rate variability (HRV), different skin parameters (temperature, redness and blood flow) and self-report questionnaires. All subjects conducted a sham SR-WBV training at a low intensity (2 Hz with noise level 0) and a verum SR-WBV training at a higher intensity (6 Hz with noise level 4). They were tested before, during and after the training. Conclusions were drawn on the basis of analysis of variance.

RESULTS: Twenty-three healthy, female students participated in this study (age = 22.4 ± 2.1 years; body mass index = 21.6 ± 2.2 kg/m2). Muscular activity of the TD and energy expenditure rose during verum SR-WBV compared to baseline and sham SR-WBV (all P < 0.05). Muscular relaxation after verum SR-WBV was higher than at baseline and after sham SR-WBV (all P < 0.05). During verum SR-WBV the levels of HRV were similar to those observed during sham SR-WBV. The same applies for most of the skin characteristics, while microcirculation of the skin of the middle back was higher during verum compared to sham SR-WBV (P < 0.001). Skin redness showed significant changes over the three measurement points only in the middle back area (P = 0.022). There was a significant rise from baseline to verum SR-WBV (0.86 ± 0.25 perfusion units; P = 0.008). The self-reported chronic pain grade indicators of pain, stiffness, well-being, and muscle relaxation showed a mixed pattern across conditions. Muscle and joint stiffness (P = 0.018) and muscular relaxation did significantly change from baseline to different conditions of SR-WBV (P < 0.001). Moreover, muscle relaxation after verum SR-WBV was higher than after sham SR-WBV (P < 0.05).

CONCLUSION: Verum SR-WBV stimulated musculoskeletal activity in young healthy individuals while cardiovascular activation was low. Training of musculoskeletal capacity and immediate increase in musculoskeletal relaxation are potential mediators of pain reduction in preventive trials.

Keywords: Musculoskeletal system; Electromyography; Quasi-experimental study; Prevention; Relaxation

Core tip: Musculoskeletal function improves after application of stochastic whole body vibration (SR-WBV). The pathway of the beneficial effect, however, is unclear. This study shows SR-WBV to increase muscle activity of descending trapezius muscle, the muscle that is often associated with reported pain in computer work. Participants report improved muscular relaxation after SR-WBV while the cardiovascular activation was very low. In addition to ergonomic interventions SR-WBV may help to prevent trapezius muscle related pain at work.