Low-intensity resistance training to improve knee extension strength in community-dwelling older adults: Systematic review and meta-analysis of randomized controlled studies
Midori Kamiya, Hikaru Ihira, Yoshiaki Taniguchi, Daisuke Matsumoto, Tomoya Ishigaki, Akio Okamae, Tatsuya Ogawa, Shogo Misu, Toshinori Miyashita, Takeshi Ohnuma, Tomohisa Chibana, Natsu Morikawa, Tome Ikezoe, Hyuma Makizako
Abstract
AIM: The purpose of this systematic review and meta-analysis was to investigate the effects of low-intensity resistance training on knee extension strength with respect to intensity, frequency, duration and training site in community-dwelling older adults. METHODS: A literature search was conducted for articles published up to December 2018 on PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Physiotherapy Evidence Database (PEDro), OTseeker and Ichushi-Web. Randomized controlled trials involving resistance training with <60 % one repetition maximum (1RM) in community-dwelling older adults aged 60 years and older were eligible. RESULTS: In total, 7 studies involving 275 participants were included in the meta-analysis. The results showed significant improvements in knee extension strength with low-intensity resistance training [standardized mean difference (SMD) 0.62, 95 % confidence interval (CI) 0.32 to 0.91]. In subgroup analyses, significant improvements were observed in the group with intensity at 50-60 % 1RM (0.83, 0.46 to 1.19), but not in the group at 40 % or less 1RM (0.30, 95%CI: -0.08 to 0.68). Concerning frequency, there were significant improvements in knee strength for those receiving training three times (0.90, 0.52 to 1.27) and two times (0.36, 0.03 to 0.69) per week, with a significant difference between the groups (p = 0.04). CONCLUSIONS: Low-intensity resistance training should be considered as an effective intervention to improve knee extension strength in community-dwelling older adults. Older adults may show more improvement in knee extension strength if intensity of the training is set at 50-60 % 1RM and frequency of training is three times per week.