Effects of short-term strength training on body composition, muscle strength and functional capacity of elderly: a systematic review and meta-analysis
To examine the effects of short-term strength training (STST) on different manifestations of muscle strength in the lower limbs, functional capacity and body composition of people 65 years old or older. We searched the electronic databases (PubMed, Web of Science and Cochrane) to identify all publications using STST (up to 12 weeks) in people aged 65 or older, published in the last five years, prior to May 2018. Results were analyzed as continuous data using random effects to calculate the standardized mean difference (SMD) and the 95% confidence interval (95%CI). 28 studies with 921 subjects met the inclusion criteria and were analyzed. These works were grouped into three categories for analysis: Muscular Strength, Functional Capacity and Body Composition. In Muscular Strength category, the overall pooled effect estimate was 0.95 (95%CI: 0.63; 1.26), with a significant STST effect (Z= 5.93; p<0.001), over the different strength manifestations analyzed. In Functional Capacity category, the STST decreased the Time Up-and-Go test run time (SMD: -1.01; 95%CI: -1.56; -0.47) and increased the repetitions’ number performed in 30-s chair-stand test (SMD: 1.07, 95% CI: 0.79, 1.34). In Body Composition category, the overall pooled effect estimate was 0.13 (95%CI: -0.16; 0.42), without finding a significant effect of STST (Z= 0.87; p= 0.38). STST has a moderate to large effect in improving the different manifestations of muscle strength and functional capacity. However, this type of intervention has no effect on body composition.