Efeito das variáveis do treinamento resistido sobre a densidade mineral óssea em mulheres na pós-menopausa: uma revisão sistemática e metanálise

Abstract

The transition from menopause leads to a reduction in BMD. Resistance training has been suggested as a non-pharmacological intervention to prevent bone decline due to the positive effects on bone mineral density (BMD). However, there is still disagreement about the effect of RT variables on BMD in postmenopausal women (PMW). Understanding the effects of TR variables can assist in the development of adequate protocols to prevent or treat low BMD in PM. Aiming to determine the effect (size) of RT on BMD in the lumbar spine, femoral neck and trochanter in postmenopausal women. The secondary objective was to identify, by subgroup analysis, the RT variables relevant to the effect of RT on BMD. Systematic searches were carried out systematic searches in two electronic databases, PUBMED and EMBASE. The quality of the studies was assessed using the PEDro scale. Effect sizes were estimated in terms of the standardized mean difference (SMD). And subgroup analyzes were conducted by training variables. Results were found with positive effect of RT on BMD in the trochanter region (SMD = 0.33, 95% CI: 0.10 - 0.56 and P = 0.005) and in the lumbar spine (SMD = 0.30, 95% CI: 0.05 - 0.55 and P = 0.017). There was no effect of RT on the femoral neck. However, there was high heterogeneity for the lumbar spine and femoral neck. According to the subgroup analysis, a difference was observed in the training frequency (Lumbar spine: SMD = -0.589 and P = 0.025; Femoral neck: SMD: -0.734 and P = 0.036), demonstrating greater effect sizes for the lower training frequency (2 times, vs. 3 times). For the lumbar spine, there was a negative effect of the weekly volume measured in tons (SMD: -0.010 and P = 0.05). For the femoral neck, a difference was observed in the number of exercises used in training (SMD: -0.607 and P = 0.029), demonstrating greater effect sizes for the smaller number of exercises (≤ 8 exercises). In conclusion, through this systematic review and meta-analysis observed a low effect of RT on BMD in the regions of the trochanter and lumbar spine, but with no effect on the femoral neck. However, the subgroup analysis indicated that the training variables, such as frequency, volume and number of exercises, interfere with the effects of RT on the BMD of the femoral neck and lumbar spine. Thus, the amount of exercise should be considered when prescribing RT in order to improve BMD in PMW.