RESUMEN
There is a recent and growing interest in assessing differential responders to resistance training (RT) for diverse outcomes. Thus, the individual ability to respond to an intervention for a specific measurement, called responsiveness, remains to be better understood. Thus, the current study aimed to summarize the available information about the effects of RT on functional performance and muscle strength, power, and size in healthy adults, through the prevalence rate in different responsiveness classifications models. A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and was registered at the International Prospective Register of Systematic Reviews (PROSPERO, CRD42021265378). PubMed/MEDLINE, Scopus, and Embase databases were systematically searched in October 2023. A total of 13 studies were included, totaling 921 subjects. Only two studies presented a low risk of bias. Regarding the effectiveness of RT, the prevalence rate for non-responders ranged from 0% to 44% for muscle strength, from 0% to 84% for muscle size, and from 0% to 42% for functional performance, while for muscle power, the only study found showed a responsiveness rate of 37%. In conclusion, a wide range of differential responders is described for all variables investigated. However, the evidence summarized in this systematic review suggested some caution while interpreting the findings, since the body of evidence found seems to be incipient, and widely heterogeneous in methodological and statistical aspects.
RESUMEN
OBJECTIVE: The aim of this study was to compare the effects of 12 weeks of traditional resistance training (TRT) or resistance training using Cluster-set (CS) on functional performance and physical fitness of postmenopausal and elderly women. METHODS: Participants (61.1 ± 4.9 years, body mass 64.5 ± 1.8 kg, height 155.7 ± 4.7 cm) were randomized to TRT (n = 35) or CS (n = 31). Anthropometric measures, muscle strength and power, gait speed, core stability, flexibility, and functional performance tests were performed before and after 12 weeks of training. The difference between protocols was the structure of rest intervals. The TRT group performed 120 s of rest between sets of 8 repetitions, while the CS performed 30 s of rest after every 2 repetitions. Two-way ANOVA with repeated measures was applied for each variable and, when needed, the Bonferroni post hoc was used. Statistical significance was set at p < 0.05. RESULTS: No group by time interaction was found for any variable. Regarding between-moment comparisons, there were significant improvements for 1 repetition maximum (RM) bench press (F = 104.6; ηp2 = 0.62; p < 0.001), 1RM leg press (F = 74.6; ηp2 = 0.53; p < 0.001), medicine ball throw (F = 64.0; ηp2 = 0.26; p < 0.001), standing long jump (F = 27.6; ηp2 = 0.30; p < 0.001), countermovement jump (F = 17.4; ηp2 = 0.21; p < 0.001), squat jump (F = 23.2; ηp2 = 0.26; p < 0.001), plank time (F = 31.6; ηp2 = 0.33; p < 0.001), 6 m walking test (F = 18.0; ηp2 = 0.22; p < 0.001), sit-to-stand test (F = 20.4; ηp2 = 0.24; p < 0.001), sit and reach test (F = 56.8; ηp2 = 0.47; p < 0.001) and 2 kg elbow curls (F = 15.9; ηp2 = 0.19; p < 0.001). CONCLUSION: Considering that both CS and TRT methods were equally effective to improve the physical fitness and functionality of elderly women, the decision of which protocol to use should be based on individual preferences and practical aspects.