Does Exercise Intervention Improve Muscle Strength and Balance of Japanese Subjects with Osteoporosis?: a Systematic Review and Meta-analysis of Randomized Controlled Trials

[Purpose] The purpose of this study was to confirm the positive effect of exercise intervention on risk factors of falls for Japanese subjects with osteoporosis (OP). [Subjects and Methods] A systematic review and meta-analysis of randomized controlled trials were performed to investigate the effect of exercise on muscle strength and balance, which are risk factors of falls for Japanese subjects with OP. The electronic databases of PubMed, CENTRAL, PEDro, CINAHL, and Ichushi-Web were searched. In the process of systematic review and meta-analysis, the Preferred Reporting Items for Systematic Reviews and Meta-analyses Statement protocol (PRISMA) was used. [Results] Three studies (4 exercise groups) were included in our review. These studies used exercise interventions to improve handgrip, trunk extensor muscle strength, knee extensor muscle strength, static balance, and dynamic balance. Regardless of final measurement outcome, none of the studies showed that the exercise group had a better result than that of the control group in terms of muscle strength or balance. Synthesized data did not reveal a positive effect of exercise intervention on trunk extensor muscle strength. [Conclusion] Our results do not provide high-quality evidence that muscle strength and balance, which are risk factors for falls, are improved by exercise intervention for Japanese subjects with OP.