Felipe Segura-Ortiz

Anabolic resistance, consisting of a diminished ability of aging muscle to respond to anabolic stimuli such as exercise and protein intake, is a key contributor to age-related declines in muscle mass. However, diseases and lifestyle factors associated with aging, including insulin resistance states, overweight/obesity, persistent inflammation and specifically—as a focus herein—physical inactivity and inadequate dietary protein-intake habits, might interact with chronological impairments in muscle anabolism. In this context, master athletes, as individuals who have engaged in lifelong structured exercise, including regular training and sports participation, offer a valuable model for studying processes of chronological vs. inactivity-related aging. While these lifelong exercisers may present improved body composition parameters and other potential benefits in terms of muscle mass and function, it remains unclear whether exercise practice throughout life can prevent the development of anabolic resistance associated with aging. Albeit limited, evidence has indicated that even in lifelong-trained older individuals there is a blunted post-exercise muscle anabolic response compared to younger athletes. However, there is a paucity of data to systematically understand the differences in postprandial anabolic response to varying protein doses in older vs. young athletes. In lieu of the above, it seems reasonable that master athletes may benefit from increasing protein intake closer to the upper limit of current recommendations (1.6–2.0 g/kg/day). In addition, supplementing their diet with ingredients that have established anabolic potential, including branched chain amino acids (BCAAs) such as leucine, the leucine metabolite β-hydroxy-β-methylbutyrate (HMB), and n3-polyunsaturated fatty acids (n3-PUFA), may potentiate the anabolic response to protein and exercise.

Background: Bioelectrical impedance analysis (BIA) is a widely used field technique for assessing body composition in football. However, its reliance on population-specific regression equations limits its accuracy. Objective: This scoping review aimed to map the scientific literature on BIA applications in professional and semi-professional football, highlighting uses, limitations, and research opportunities. Methods: A comprehensive search was conducted in the scientific databases PubMed, EMBASE, Web of Science, and SPORTDiscus. Identified studies involved the use of BIA in professional and semi-professional football players (≥16 years) in the context of routine training and competition. Results: From 14,624 records, 39 studies met the inclusion criteria and were included. Three main applications were identified: (1) quantitative body composition assessment, (2) qualitative/semi-quantitative analysis (e.g., bioelectrical impedance vector analysis (BIVA)), and (3) muscle health and injury monitoring. Seven specific research areas emerged, including hydration monitoring, cross-method validation of body composition analyses, development of predictive models, sport phenotype identification, tracking training adaptations, performance/load assessment via phase angle, and localized BIA for injury diagnosis and recovery. Conclusions: While quantitative BIA estimates may lack individual-level precision, raw parameter analyses may offer valuable insights into hydration, cellular integrity, and muscle injury status, yet further research is needed to fully realize these applications.