Optimizing resistance training for body recomposition in postmenopausal women

We investigated the effectiveness of a resistance training (RT) protocol with lower volume and lower load in the body recomposition of postmenopausal women, and to determine whether changes in body recomposition induced by RT would be associated with changes in physical performance, independently of confounding factors. Participants were randomly assigned to one of three groups: I) Single set-high load (SSHL, n = 14, 1 set of 8 to 12 maximum repetitions), II) Single set-low load (SSLL, n = 15, 1 set of 25 to 30 maximum repetitions), and III) Multiple sets-high load (MSHL, n = 14, 3-6 sets of 8 to 12 maximum repetitions). The study extended over a duration of 27 weeks, encompassing 24 weeks of RT. We assessed body composition using dual-energy X-ray absorptiometry, physical performance using the Timed Up and Go and sit and stand tests, and muscle strength using the one-repetition maximum (1RM) test. We quantified body recomposition using a composite z score calculated as follows: (appendicular lean mass % delta z score) + (- 1 x fat mass delta % z score) / 2. Results showed significant improvements in physical performance (P < 0.001), significant reductions in visceral adipose tissue, total fat mass, and % fat (P = 0.003, P = 0.042, and P < 0.001, respectively), and increases in muscle mass and strength (P < 0.001), regardless of group assignment. Notably, the higher load groups (SSHL and MSHL) had significantly greater body recomposition compared to the lower load group (SSLL), particularly after adjusting for age, physical activity, and sitting time (P = 0.028). Therefore, the higher load of RT is a critical factor in the body recomposition of postmenopausal women. Furthermore, the positive effects of body recomposition induced by RT extend to physical performance and muscle strength.