Evaluation of 18-week whole-body vibration training in normobaric hypoxia on lower-extremity muscle strength in elderly population

Abstract

Therapeutic benefits of hypoxic training have been suggested for clinical populations, such as elderly who could suffer loss of lower limb muscle strength and higher risk of falling. This study investigated the effects of 18 weeks of whole-body vibration (WBV) training in normobaric hypoxia on the strength parameters of an elderly population. Thirty-one healthy elderly participants were randomly assigned to a hypoxic whole-body vibration group (HWBV; n = 10), normoxic whole-body vibration group (NWBV; n = 11), or control group (n = 10). The experimental groups received the same vibration treatment in a hypoxia chamber (HWBV: 16.1% fraction of inspired oxygen [FiO2]; NWBV: 21.0% FiO2). Isokinetic leg muscle strength was evaluated using a Biodex System-3 isokinetic dynamometer. Body composition was obtained with dual-energy X-ray absorptiometry. There were no significant differences between groups in either strength or body composition parameters. The NWBV group showed statistically significant improvements in the maximal strength of knee extensors, with a small effect size ( p = 0.004; d = 0.54). No significant differences were found in any variable of the HWBV group. The combination of WBV training and exposure to normobaric cyclic hypoxia carried out in the present study did not have an effect on strength parameters in healthy elderly subjects.