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Background To propose cut-off points for older adults’ weakness for upper and lower limbs muscle strength normalized by body size with the ratio standard/muscle quality and allometric scaling. Methods Ninety-four community-dwelling older adults (69.1% women) were assessed for 49 body-size variables (anthropometry, body composition and body indexes), handgrip strength (HGS), one maximum repetition measurement for knee extensors (1RM), isokinetic knee extension peak torque at 60°/s (PT), and six-minute walk test (6MWT). Ratio standard or muscle quality (muscle strength/body size) and allometric scaling (muscle strength/body sizeb; when b is the allometric exponent) were applied for body-size variables significantly correlated with HGS, 1RM and PT. Cut-off points were computed according to sex based on mobility limitation (6MWT < 400 m) with ROC curve and Youden index. Results Absolute HGS, 1RM and PT cut-off points were not adequate because they were associated with body size (r > 0.30). But it was corrected with muscle strength normalization according to body size-variables: HGS (n = 1); 1RM (n = 24) and PT (n = 24). The best cut-off points, with the highest area under the curve (AUC), were found after normalization for men: HGS/forearm circumference (1.33 kg/cm, AUC = 0.74), 1RM/triceps skinfold (4.22 kg/mm, AUC = 0.81), and PT/body mass*height0.43 (13.0 Nm/kg*m0.43, AUC = 0.94); and for women: HGS/forearm circumference (1.04 kg/cm, AUC = 0.70), 1RM/body mass (0.54 kg/kg, AUC = 0.76); and PT/body mass0.72 (3.14 Nm/kg0.72; AUC = 0.82). Conclusions Upper and lower limbs muscle weakness cut-off points standardized according to body size were proposed for older adults of both sexes. Normalization removes the effect of extreme body size on muscle strength (both sexes) and improves the accuracy to identify weakness at population level (for women, but not in men), reducing the risk of false-negative/positive cases.

Background: Dynamic knee extensor muscle strength is a valid measure among healthy older adults but has not been tested in the sarcopenia condition. This study's objective was to test the validity of a one-repetition submaximal strength protocol to measure dynamic knee extension strength in older adults with and without sarcopenia. Methods: Ninety-four physically independent older adults (female: n = 64, 60 to 85 years; male: n = 29, 60 to 85 years) participated in this study in Brazil during 2016-2017. Sarcopenia was classified and isokinetic unilateral knee extension strength was measured at 60°/s. Bilateral dynamic knee extension strength was estimated with an extensor chair using one-repetition submaximal protocol. Validity was determined using Spearman's correlation with isokinetic muscle strength. Results: The frequency of sarcopenia was 11.7%. Sarcopenic individuals presented lower body mass, body mass index and skeletal muscle index. Only chronological age was higher among the sarcopenic individuals. A high correlation was found between isokinetic unilateral knee extension strength and bilateral estimated one-repetition with submaximal protocol (r = 0.74; p < 0.001), when the presence (r = 0.71; p = 0.014) and absence of sarcopenia (r = 0.74; p < 0.001) were considered. The validity of the one-repetition submaximal protocol for bilateral knee extension was confirmed. Conclusions: The estimated measure of bilateral knee extension muscle strength can be used to monitor adaptations promoted by physical exercise for older adults with and without sarcopenia. The validation enable studies that will propose cutoff points to identify sarcopenia with this submaximal protocol. This will enable early diagnosis and better management of sarcopenia, a disease with adverse impacts for older adults.

BackgroundBody composition alterations, or lipodystrophy, can lead to serious health problems in people living with HIV/AIDS (PLWHA). The objectives of this study are to predict and validate sex-specific anthropometric predictive models for the diagnosis of lipodystrophy in PLWHA.MethodsA cross-sectional design was employed to recruit 106 PLWHA (men = 65 and women = 41) in Brazil during 2013–2014. They were evaluated using dual-energy X-ray absorptiometry, and 19 regions of body perimeters and 6 skinfold thicknesses were taken. Sex-specific predictive models for lipodystrophy diagnosis were developed through stepwise linear regression analysis. Cross-validations using predicted residual error sum of squares was performed to validate each predictive model.ResultsResults support the use of anthropometry for the diagnosis of lipodystrophy in men and women living with HIV/AIDS. A high power of determination with a small degree of error was observed for lipodystrophy diagnosis for men in model six (r2 = 0.77, SEE = 0.14, r2PRESS = 0.73, SEE PRESS = 0.15), that included ratio of skinfold thickness of subscapular to medial calf, skinfold thickness of thigh, body circumference of waist, formal education years, time of diagnosis to HIV months, and type of combined antiretroviral therapy (cART) (with protease inhibitor “WI/PI = 1” or without protease inhibitor “WO/PI = 0”); and model five for women (r2 = 0.78, SEE = 0.11, r2PRESS = 0.71, SEE PRESS = 0.12), that included skinfold thickness of thigh, skinfold thickness of subscapular, time of exposure to cART months, body circumference of chest, and race (Asian) (“Yes” for Asian race = 1; “No” = 0).ConclusionsThe proposed anthropometric models advance the field of public health by facilitating early diagnosis and better management of lipodystrophy, a serious adverse health effect experienced by PLWHA.

The aim of the study was to compare the impact of 12-week resistance training with blood flow restriction (G RTBFR ) versus, traditional resistance training (G TRT ) and non-training on the muscle strength and body composition HIV/AIDS participants. Muscle strength was tested at baseline, and on the 6th, 21st and 36th training sessions, using maximal repetition test. Pre-and post-intervention body composition changes were measured by dual-energy X-ray absorptiometry. Resistance training was undertaken three times a week comprising bilateral elbow extension and flexion exercises, unilateral flexion and bilateral knee extension. Changes in strength and body composition (pre-and post-intervention) between groups were evaluated by mixed models of repeated measures, and by paired and unpaired comparisons, considering the Effect Size. All groups were similar at baseline for muscle strength and body composition. Post-intervention, the training groups showed similar, statistically significant increases in muscle strength (G RTBFR =25.7-57.4%; G TRT= 24.5-52.3%) and skeletal muscle tissue (G RTBFR =8.4%; G TRT =8.3%). There was also a significant change in body fat (p=0.023-0.043), with significant effect sizes for strength and skeletal muscle tissue (0.41-2.27), respectively. These results suggest that both resistance training interventions promoted muscle hypertrophy, body fat reduction and positive impact on muscle strength in people living with HIV/AIDS. Resistance training with blood flow restriction proved to be an effective alternative to include patients with marked physical weakness, unable to engage in regular strength training programme.ClinicalTrials.gov identifier: NCT02783417.

O sobrepeso e o desenvolvimento motor pobre nas crianças e adolescentes, que podem ser constatados em diferentes regiões e classes sociais, decorrem sobretudo do estilo de vida sedentário. Por si, o sedentarismo é um fator de risco para as doenças crônicas e mortalidade, principalmente na vida adulta, e por isso deve ser combatido desde a infância. Urbanização, desenvolvimento industrial, meios de comunicação, aparelhos eletrônicos, falta de estímulo e de exemplo dos pais se constituem num ambiente favorável para prática insuficiente de atividades físicas por até 81% das crianças e adolescentes. Por outro lado, há grande número de possibilidades para prática de exercícios de intensidade moderada a vigorosa, que efetivamente possam proporcionar benefícios para os jovens. Quando a Educação Física escolar não é suficiente, seja por seu conteúdo ou limitação de número de aulas, as escolas de esportes, os exercícios de musculação nas academias, o treinamento funcional e o CrossFit estão entre as opções que podem motivar os jovens. Os esportes e modalidades de treinamento proporcionam o desenvolvimento de uma gama de capacidades físicas, o pleno desenvolvimento somático e de aspectos cognitivos e emocionais. Cabem aos pais dois importantes papéis neste início de caminhada dos filhos para o estilo de vida ativo. Em primeiro estimular e deixar de lado crenças e informações enganosas sobre riscos de algumas modalidades de treinamento; em segundo garantir que os filhos pratiquem a modalidade escolhida sob supervisão de um profissional de Educação Física, de forma a garantir a correção postural durante os exercícios, execução correta dos movimentos, o feedback para os aprendizes, a adequada densidade das sessões e o cumprimento dos princípios do treinamento físico para proporcionar os melhores benefícios.

Normalizing calf circumference to identify low skeletal muscle mass in older women: a cross-sectional studyNormalización de la circunferencia de la pantorrilla para identificar la masa muscular esquelética baja en las mujeres mayores: un estudio transversal

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