Effects of short-term strength training on body composition, muscle strength and functional capacity of elderly: a systematic review and meta-analysis / Efeitos do treinamento de força de curta duração sobre a composição corporal, a força muscular e a capacidade funcional de idosos: revisão sistemática e meta-análise

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.

Examinar os efeitos do treinamento de força de curta duração (TFCD) em diferentes manifestações de força muscular nos membros inferiores, capacidade funcional e composição corporal de pessoas maiores de 65 anos. Foram pesquisadas bases de dados eletrônicas (PubMed, Web of Science e Cochrane) para identificar todas as publicações utilizando TFCD (até 12 semanas) em pessoas maiores de 65 anos, publicadas nos últimos cinco anos, antes de maio de 2018. Os resultados foram analisados como dados contínuos usando efeitos aleatórios para calcular a diferença padronizada da média (SMD) e o intervalo de confiança de 95% (IC95%). 28 estudos com 921 sujeitos preencheram os critérios de inclusão e foram analisados. Esses trabalhos foram agrupados em três categorias para análise: Força Muscular, Capacidade Funcional e Composição Corporal. Na categoria Força Muscular, a estimativa geral do efeito combinado foi de 0,95 (95% CI: 0,63; 1,26), com um efeito significativo do TFCD (Z = 5,93; p <0,001), sobre as diferentes manifestações de força analisadas. Na categoria Capacidade Funcional, o TFCD diminuiu o tempo de execução do teste Timed Up-and-Go (SMD: -1.01; 95% CI: -1.56; -0.47) e aumentou o número de repetições realizadas no teste de levantar e sentar na cadeira de 30 segundos (SMD: 1,07, IC 95%: 0,79, 1,34). Na categoria de Composição Corporal, a estimativa geral do efeito combinado foi de 0,13 (IC 95%: -0,16; 0,42), sem encontrar efeito significativo do TFCD (Z = 0,87; p = 0,38). O TFCD apresenta efeito moderado a grande na melhora das diferentes manifestações de força muscular e capacidade funcional. No entanto, este tipo de intervenção não tem efeito sobre a composição corporal.

Efecto del ejercicio agudo sobre la expresión del receptor tipo Toll-4 y los mecanismos inflamatorios en corazón de rata / Effect of an acute exercise bout on Toll-like receptor 4 and inflammatory mechanisms in rat hear

Background: Toll like receptor 4 (TLR-4) is a protein located in the cell membrane with an important function in the immune response of the organism. Its activation decreases heart contractility and activates nuclear transcription factor kappa B (NF-kB ). This in turn, increases the synthesis of different pro-inflammatory cytokines and the inducible enzyme nitric oxide (iNOS), which plays an important role in the inflammatory processes when nitric oxide production is enhanced. Aim: To determine if, after one session of acute exercise, expression of TLR-4 and iNOS, and activation of NF-kB are induced in rat cardiac tissue. Material and Methods: Exercise and control groups of eight male Wistar rats each, were studied. The exercise group was subjected to an acute exercise bout lasting one hour. After the exercise, the heart was excised to measure the expression of iNOS and TLR-4 genes by quantitative polyme-rase chain reaction, NF-kB activation by electrophoretic mobility shift assay (EMSA) and p50 by Western blot. Results: After exercise, there was an increase in TLR-4 and of iNOS mRNA levels (+46.7 and +74.3% respectively). NF-kB activation and the nuclear expression of its p50 subunit also increased significantly (+240 and +306% respectively). Conclusions: Increased expression of TLR4 following a session of acute exercise may contribute to the activation of the NF-kB signaling route, promoting the synthesis of nitric oxide, which could influence negatively the cardiac response to high intensity physical exercise.