Skilling up for training: a feasibility study investigating acute effects of stochastic resonance whole-body vibration on postural control of older adults

Abstract

The present pilot study investigated the feasibility of applying a single bout stochastic resonance whole-body vibration in deconditioned elderly individuals and the effects on static and dynamic balance and reaction time. We report the results of a non-blinded randomized control trial with a pre-test/post-test design. Twenty elderly individuals were randomized into either single bout stochastic resonance whole-body vibration (SR-WBV) (n=10, frequency 5 Hz, Noise 4) or control (n=10). SR-WBV received 5 sets of 1 min stochastic whole-body vibration (5 Hz, Noise 4: vibration with a randomly varying frequency, 1=low, 4=high) with 1 min rest in between. The control group rested for 10 min without any intervention. Functional reach test (FRT), semi-tandem stand (STS), Expanded Timed Get Up-and-Go Test (ETGUG), single task- (ST) and dual task walking time (DT), chair rising (CR), and foot (RTF) and hand reaction time (RTH) were measured before and after the intervention. Within- and between group differences were analyzed using repeated measures. In order to assess the meaningfulness of pre-training to post-training changes, the effect size (ES) was calculated according to Cohen’s d. All participants in the study accepted and adhered to the WBV session and performed scheduled follow-up measurements. There were no adverse events. Change values for dynamic balance showed a strong trend towards improvement for FRT of about 4.5% (ES=0.52, P=0.161). Change values for RTF (5.9%; ES=0.55; P =0.169) showed a trend towards improvement in the SR-WBV only. The results suggest that stochastic resonance WBV is both safe and well accepted by elderly individuals in assisted living institutions, and might have beneficial effects on balance in these adults. Further research is warranted to determine whether this device might be of use in the <em>skilling-up</em> phase of an exercise program when training is initiated in strongly deconditioned and/or frail elderly. The new training protocol is expected to allow for safe <em>skilling-up</em> training of deconditioned older adults in assisted living institutions.