Background: Body composition (BC) in the elderly has been associated with diseases and mortality; however, there is a shortage of data on frailty in the elderly. Objective: To investigate the association between BC and frailty, and identify BC profiles in nonfrail, prefrail, and frail elderly people. Methods: A cross-sectional study comprising 235 elderly (142 females and 93 males) aged ≥65 years, from the city of Amparo, State of São Paulo, Brazil, was undertaken. Sociodemographic and cognitive features, comorbidities, medication, frailty, body mass index (BMI), muscle mass, fat mass, bone mass, and fat percent (%) data were evaluated. Aiming to examine the relationship between BC and frailty, the Mann–Whitney and Kruskal–Wallis nonparametric tests were applied. The statistical significance level was P<0.05. Results: The nonfrail elderly showed greater muscle mass and greater bone mass compared with the prefrail and frail ones. The frail elderly had greater fat % than the nonfrail elderly. There was a positive association between grip strength and muscle mass with bone mass (P<0.001), and a negative association between grip strength and fat % (P<0.001). Gait speed was positively associated with fat mass (P=0.038) and fat % (P=0.002). The physical activity level was negatively associated with fat % (P=0.022). The weight loss criterion was positively related to muscle mass (P<0.001), bone mass (P=0.009), fat mass (P=0.018), and BMI (P=0.003). There was a negative association between fatigue and bone mass (P=0.008). Discussion: Frailty in the elderly was characterized by a BC profile/phenotype with lower muscle mass and lower bone mass and with a higher fat %. The BMI was not effective in evaluating the relationship between BC and frailty. The importance of evaluating the fat % was verified when considering the tissue distribution in the elderly BC.

Background: Bioelectrical Impedance Analysis (BIA) is a fast, practical, non-invasive, and frequently used method for fat-free mass (FFM) estimation. The aims of this study were to validate predictive equations of BIA to FFM estimation in Army cadets and to develop and validate a specific BIA equation for this population. Methods: A total of 396 males, Brazilian Army cadets, aged 17–24 years were included. The study used eight published predictive BIA equations, a specific equation in FFM estimation, and dual-energy X-ray absorptiometry (DXA) as a reference method. Student’s t-test (for paired sample), linear regression analysis, and Bland–Altman method were used to test the validity of the BIA equations. Results: Predictive BIA equations showed significant differences in FFM compared to DXA (p < 0.05) and large limits of agreement by Bland–Altman. Predictive BIA equations explained 68% to 88% of FFM variance. Specific BIA equations showed no significant differences in FFM, compared to DXA values. Conclusion: Published BIA predictive equations showed poor accuracy in this sample. The specific BIA equations, developed in this study, demonstrated validity for this sample, although should be used with caution in samples with a large range of FFM.

The military are selected on the basis of physical standards and are regularly involved in strong physical activities, also related to particular sports training. The aims of the study were to analyze the effect of a 7-month military training program on body composition variables and the suitability of specific ‘bioelectrical impedance vector analysis’ (spBIVA), compared to DXA, to detect the changes in body composition. A sample of 270 male Brazilian cadets (19.1 ± 1.1 years), composed of a group practicing military physical training routine only (MT = 155) and a group involved in a specific sport training (SMT = 115), were measured by body composition assessments (evaluated by means of DXA and spBIVA) at the beginning and the end of the military routine year. The effect of training on body composition was similar in SMT and MT groups, with an increase in LST. DXA and spBIVA were correlated, with specific resistance (Rsp) and reactance (Xcsp) positively related to fat mass (FM), FM%, LST, and lean soft tissue index (LSTI), and phase angle positively related to LST and LSTI. Body composition variations due to physical training were recognized by spBIVA: the increase in muscle mass was indicated by the phase angle and Xcsp increase, and the stability of FM% was consistent with the unchanged values of Rsp. Military training produced an increase in muscle mass, but no change in FM%, independently of the sample characteristics at baseline and the practice of additional sports. SpBIVA is a suitable technique for the assessment of body composition in military people.

INTRODUÇÃO: Exércitos do mundo inteiro reconhecem a importância de uma boa condição física para o desempenho das funções militares. O treinamento físico militar (TFM) tenta proporcionar auxílio nessa busca por uma melhor condição física e corporal. OBJETIVO: Verificar o efeito de 13 semanas de TFM na composição corporal e no desempenho físico dos alunos da Escola Preparatória de Cadetes do Exército (EsPCEx). MÉTODOS: A amostra foi constituída de 287 alunos do sexo masculino da EsPCEx com idade média de 18,33 ± 1,26 anos. Tais alunos cumpriram uma rotina de internato, com horários, refeições e atividades definidas, da qual eram liberados somente nos finais de semana. O TFM foi realizado numa frequência semanal de cinco dias e englobou treinamentos aeróbicos e resistivos. Foram realizadas no período pré e pós-treinamento medidas da massa corporal, altura, dobras cutâneas (tricipital, abdominal e suprailíaca) e realizados os seguintes testes: corrida de 12 minutos, abdominal parafuso, flexão de braço e flexão na barra fixa. Com os dados antropométricos coletados, foi calculado o percentual de gordura, massa livre de gordura (MLG) e massa gorda (MG) baseado no protocolo de três dobras de Guedes. RESULTADOS: Quando comparados os valores dos dados antropométricos e da composição corporal dos períodos inicial e final de treinamento foi observada redução significativa na MG, no percentual de gordura, nas dobras cutâneas tricipital e abdominal e aumento na dobra cutânea suprailíaca e na MLG. Ocorreram melhoras significativas também em todos os testes físicos realizados, nos quais um melhor desempenho foi alcançado. CONCLUSÃO: Os dados obtidos sugerem melhora significativa na composição corporal e no desempenho físico através da realização do TFM, com frequência semanal de cinco dias.