Independent and combined effect of home-based progressive resistance training and nutritional supplementation on muscle strength, muscle mass and physical function in dynapenic older adults with low protein intake: A randomized controlled trial.

BACKGROUND: With the aging phenomenon, there is growing interest in developing effective strategies to counteract dynapenia, the age-related loss of muscle strength. The positive effect of progressive resistance training on muscle strength is well known, however, the effect of nutritional supplementation or its synergistic effect along with exercise on muscle strength is not a consensus in the literature, especially in populations with low protein intake. METHODS: We analyzed the muscle strength (handgrip strength and sit-to-stand test), muscle mass, body mass index, insulin resistance, and physical function (gait speed, timed up & go test, and single-leg-stance test) of 69 dynapenic older adults with low protein intake, before and after the intervention period of three months. The participants were randomly allocated into four groups: resistance training, supplementation, resistance training plus supplementation, and control. RESULTS: There was a significant group x time interaction on the following outcome measures: handgrip strength (p <  0.001), gait speed (p =  0.023), and sit-to-stand test (p <  0.001). Considering the outcomes that showed a significant difference between and within groups, only the resistance training group and the resistance training plus supplementation group showed a large effect size in handgrip strength, gait speed, and sit-to-stand test, whereas the supplementation group showed a moderate effect size in gait speed. After the intervention period, there was no difference between the resistance training and the resistance training plus supplementation groups. CONCLUSION: This study reinforces the value of resistance training in improving muscle strength. The nutritional supplementation added no further benefits in this specific population. Registration number at the Brazilian registry of clinical trials: RBR-4HRQJF.

Associação entre adiposidade, índice de massa corporal, força de preensão palmar e velocidade de marcha em idosos comunitários / Association between adiposity, body mass index, grip strength and walking speed in community-dwelling elderly

Esta pesquisa objetivou avaliar a relação entre índice de massa corporal e adiposidade com força de preensão palmar e velocidade de marcha em idosos. É um estudo transversal aninhado em um estudo de intervenção com idosos comunitários assistidos por Unidades Básicas de Saúde no Município de Diamantina/MG. Foram avaliados dados socioeconômicos, antropométricos, de adiposidade, clínicos, bioquímicos, de força de preensão palmar e de velocidade de marcha. Testes de correlação de Pearson ou Spearman e regressão linear foram utilizados na análise dos dados. Foram estudados 49 idosos, com idade média de 77,21 ± 6,24 anos e predomínio de mulheres (69,29%). Valores elevados de adiposidade e índice de massa corporal ocorreram respectivamente em 69,39% e 34,69% dos idosos. A análise de regressão, estratificada por gênero e ajustada por variáveis de controle, indica que os índices de massa corporal e adiposidade não se associaram à força de preensão palmar e à velocidade de marcha dos idosos. No entanto, na análise considerando a amostra geral, a adiposidade influenciou negativamente na força de preensão palmar (para cada aumento de 1% na adiposidade, há uma redução de 0,226 kg no valor desta variável). Em relação à velocidade de marcha, a cada aumento de um ano de vida há uma redução de 0,014 m/s no valor desta variável, e o aumento de cada kg na força causa um aumento de 0,0193 m/s na velocidade de marcha. Pode-se concluir que a adiposidade e a idade influenciaram negativamente na força de preensão palmar dos idosos avaliados, e maior força influenciou positivamente na velocidade de marcha. (AU)

The objective of this research is to evaluate the relationship between body mass index and adiposity with handgrip strength and gait speed in the elderly. It is a cross-sectional study nested in an intervention study with community-based elderly people assisted by Basic Health Units in the municipality of Diamantina/MG. Socioeconomic, anthropometric, adiposity, clinical, biochemical, handgrip strength and gait velocity data were evaluated. Pearson or Spearman correlation tests and linear regression were used in data analysis. We studied 49 elderly people, with mean age of 77.21 ± 6.24 years and predominance of women (69.29%). High values of adiposity and body mass index occurred respectively in 69.39% and 34.69% of the elderly. The results of the regression analysis, stratified by gender and adjusted for control variables, indicate that body mass index and adiposity were not associated with handgrip strength and gait speed of elderly. However, in the analysis considering the general sample, adiposity negatively influenced handgrip strength (for each increase of 1% in adiposity, there is a reduction of 0.226 kg in the value of this variable). Regarding the gait speed, for every full year of life, there is a reduction of 0.014 m/s in the value of this variable, and, for each kg increased in force, there is an increase of 0.0193 m/s in gait speed. It can be concluded that adiposity and age negatively influenced the handgrip strength of the evaluated elderly, and greater strength influenced positively in gait speed. (AU)