RESUMO
BACKGROUND: Ageing, inactivity and obesity are associated with chronic low-grade inflammation contributing to a variety of lifestyle-related diseases. Transforming growth factor-ß (TGF-ß) is a multimodal protein with various cellular functions ranging from tissue remodelling to the regulation of inflammation and immune functions. While it is generally accepted that aerobic exercise exerts beneficial effects on several aspects of immune functions, even in older adults, the effect of resistance training remains unclear. The aim of this study was to investigate whether progressive resistance training (6 months) with or without nutritional supplementation (protein and vitamins) would influence circulating C-reactive protein and TGF-ß levels as well as TGF-ß signalling in peripheral mononuclear cells (PBMCs) of institutionalised adults with a median age of 84.5 (65.0-97.4) years. RESULTS: Elastic band resistance training significantly improved performance as shown by the arm-lifting test (p = 0.007), chair stand test (p = 0.001) and 6-min walking test (p = 0.026). These results were paralleled by a reduction in TGF-ß receptor I (TGF-ßRI) mRNA expression in PBMCs (p = 0.006), while circulating inflammatory markers were unaffected. Protein and vitamin supplementation did not provoke any additional effects. Interestingly, muscular endurance of upper and lower body and aerobic performance at baseline were negatively associated with changes in circulating TGF-ß at the early phase of the study. Furthermore, drop-outs of the study were characterised not only by lower physical performance but also higher TGF-ß and TGF-ßRI mRNA expression, and lower miRNA-21 expression. CONCLUSIONS: Progressive resistance training with elastic bands did not influence chronic low-grade inflammation but potentially affected TGF-ß signalling in PBMCs through altered TGF-ßRI mRNA expression. There appears to be an association between physical performance and TGF-ß expression in PBMCs of older adults, in which the exact mechanisms need to be clarified.
RESUMO
OBJECTIVES: To evaluate the effects of elastic band resistance training in combination with nutrient supplementation on muscular strength and the ability to perform mobility-related activities of daily living in older adults living in retirement care facilities. DESIGN: Randomized controlled trial, with a 6-month intervention period. SETTING: A retirement care facility, Vienna, Austria. PARTICIPANTS: One hundred and seventeen older adults (14 males (12%) and 103 females (88%)), aged 65 to 97 years (mean age: 82.8 ± 6.0), having a mini-mental state examination score ≥ 23 and no chronic diseases posing a medical contraindication to training therapy. INTERVENTION: Participants were randomly assigned, but stratified by sex, to one of three intervention groups: supervised resistance exercise training (RT), RT in combination with nutrient supplementation (RTS), or cognitive training group (CT). All interventions were performed two times a week for 6 months. RT was designed to train all major muscle groups using elastic bands. The nutrient supplement (rich in proteins, vitamin D, B2, B12) was distributed every morning as well as after each RT session. MEASUREMENTS: A battery of motor ability tests and functional test were performed prior to as well as following 3 months and finally after 6 months of intervention. These tests included isokinetic torque measurements of the knee extensors and flexors in concentric mode at 60 and 120°/s, isometric handgrip strength, senior arm-lifting test, chair stand test, maximum walking speed and a 6-minute walking test (6 MWT). RESULTS: A repeated-measures ANOVA analysis revealed significant improvements in physical function of lower (p=0.002) and upper extremities (p=0.006) for RT and/or RTS in comparison to CT. For isokinetic measurements, 6 MWT, and gait speed time effects (p<0.05) were detected without any group × time interaction effects. Dropouts showed lower performance in chair stand test (p=0.012), 6 MWT (p=0.003), and gait speed (p=0.013) at baseline than that of the finishers of the study. CONCLUSION: Six months of a low intensity resistance exercise using elastic bands and own body weight is safe and beneficial in improving functional performance of institutionalised older people. Multinutrient supplementation did not offer additional benefits to the effects of RT in improving muscular performance.