The effects of whole body vibration therapy on bone mineral density and leg muscle strength in older adults: a systematic review and meta-analysis

Objective: A systematic review and meta-analysis of randomized controlled trials was undertaken to determine whether whole body vibration improves bone mineral density and leg muscle strength in older adults. Data sources: Sources included MEDLINE, CINAHL, EMBASE, PEDro, PubMed, Science Citation Index and the reference list of each eligible article. Review methods: Article search and selection was performed independently by two researchers. The methodological quality of each selected article was rated by the PEDro scale. Results: Thirteen randomized trials (18 articles) totalling 896 subjects fulfilled the selection criteria. Four were considered to have good or excellent methodological quality and the rest were rated as fair. Meta-analyses revealed that whole body vibration has no significant effect on hip or lumbar spine bone mineral density in older women when compared with no intervention or active exercise (P > 0.05). Whole body vibration, however, had a significant treatment effect on knee extension dynamic strength (standardized mean difference = 0.63, P=0.006), leg extension isometric strength (standardized mean difference = 0.57, P = 0.003), and functional measures of leg muscle strength such as jumping height (standardized mean difference 0.51, P = 0.010) and performance in sit-to-stand (standardized mean difference = 0.72, P < 0.001) among older adults compared with no intervention. Conclusion: Whole body vibration is beneficial for enhancing leg muscle strength among older adults. However, the review suggests that whole body vibration has no overall treatment effect on bone mineral density in older women. No randomized trial has examined the effects of whole body vibration on bone mineral density in older men.