Are motivation and overtraining reliable predictors of burnout in male professional soccer athletes over the course of the season? To answer this question, 32 Brazilian athletes from the same team (age: 24.16 ± 4.58 years) participated in this study and completed the following questionnaires during different periods of the season (n = 1 baseline, n = 2 preparatory, and n = 5 competitive): the Sport Motivation Scale (SMS I), the Recovery-Stress Questionnaire for Athletes (RESTQ-Sport 76), and the Athlete Burnout Questionnaire (ABQ). The results indicated positive and negative as well as moderate and strong associations among the dimensions of motivation, overtraining and burnout. Regression analysis was used to estimate three models during the season (baseline/preparatory, baseline/competitive, and preparatory/competitive). Model 1 showed that the amotivation dimension predicts emotional and physical exhaustion (SEE = 0.39; p = 0.001; $R_{\mathrm{a}\mathrm{d}\mathrm{j}\mathrm{u}\mathrm{s}\mathrm{t}\mathrm{e}\mathrm{d}}^2$ = 0.38) and total burnout (SEE = 0.25; p = 0.001; $R_{\mathrm{a}\mathrm{d}\mathrm{j}\mathrm{u}\mathrm{s}\mathrm{t}\mathrm{e}\mathrm{d}}^2$ = 0.32). Model 2 indicated that amotivation predicts emotional and physical exhaustion (SEE = 0.32; p = 0.002; $R_{\mathrm{a}\mathrm{d}\mathrm{j}\mathrm{u}\mathrm{s}\mathrm{t}\mathrm{e}\mathrm{d}}^2$ = 0.24) and total burnout (SEE = 0.40; p = 0.001; $R_{\mathrm{a}\mathrm{d}\mathrm{j}\mathrm{u}\mathrm{s}\mathrm{t}\mathrm{e}\mathrm{d}}^2$ = 0.35). Model 3 evidenced that amotivation and sport-specific stress predict emotional and physical exhaustion (SEE = 0.19; p = 0.001; $R_{\mathrm{a}\mathrm{d}\mathrm{j}\mathrm{u}\mathrm{s}\mathrm{t}\mathrm{e}\mathrm{d}}^2$ = 0.73) and total burnout (SEE = 0.27; p = 0.001; $R_{\mathrm{a}\mathrm{d}\mathrm{j}\mathrm{u}\mathrm{s}\mathrm{t}\mathrm{e}\mathrm{d}}^2$ = 0.72). In conclusion, it was verified that the dimensions of amotivation and sport-specific stress are effective markers to predict burnout in the preparatory and competitive periods.

A síndrome de burnout no âmbito esportivo está associada ao estresse crônico e excesso de treinamento que podem levar o atleta ao encerramento da careira. Porém pouco se sabe sobre os indicadores da síndrome em atletas profissionais de futebol no Brasil.

Muscle injuries are one of the biggest medical problems in professional soccer. Evidence has suggested that genetic polymorphism is a mediating factor in physiological and structural alterations that can lead to muscle injury. The TRIM63 gene polymorphism may affect the MuRF-1 protein, which is vital in the regulation of muscle mass, and is differentially regulated by exercise mode, muscle contraction, and training status. However, central aspects of the relationship between genetic variations, the environment, and muscle injuries still need to be explained. This study aimed to investigate whether MuRF-1/TRIM63 (A/G, rs2275950) was associated with the occurrence of muscle injury in professional soccer players. Forty-six Brazilian soccer players were evaluated. Genomic DNA was extracted using blood samples and semi-structured interviews on muscle injuries were applied after two seasons (2021-2022). Fisher's exact test was used to verify if MuRF-1/TRIM63 was associated with muscle injuries. The MuRF-1/TRIM63 genotypes (c2 = 2.19; p = 0.292), the dominant model (c2 = 1.04; p = 0.299), and the recessive model (c2 = 1.94; p = 0.208) showed no association with muscle injuries in soccer players. Preliminary evidence suggests that this genetic polymorphism may not be a reliable biomarker of muscle injuries in Brazilian professional soccer players. Keywords: Football; Genetic, Muscle injury, Performance, Single Nucleotide Polymorphism (SNP), Sport genomic.

Background/Objectives: Muscle-specific RING finger protein 1 (MuRF-1) is a pivotal regulator of muscle protein breakdown, an essential process for post-exercise muscle adaptation. This systematic review aimed to evaluate the effects of physical exercise on MuRF-1 mRNA expression in humans. Methods: A literature search was conducted in PubMed, Scopus, Cochrane Library, Google Scholar, and Web of Science following the PRISMA guidelines. The search was limited to studies published from 1 January 2001 to 1 December 2024. The inclusion and exclusion criteria were defined using the PICOS strategy. Two investigators independently performed the study selection, data extraction, and assessment of methodological quality, with any disagreements resolved by a third investigator. The PEDro scale was used to evaluate the risk of bias. Results: Forty-six studies met the eligibility criteria and were included. The findings evidenced that physical exercise significantly modulates MuRF-1 mRNA expression in humans. Resistance exercise induces transient increases, typically peaking between 1 and 4 h, whereas endurance exercise elicits similar responses within 40 min to 4 h post-exercise. Combined exercise protocols that include resistance and endurance exercises significantly increased MuRF-1 mRNA expression at 3 h post-exercise. The effects of physical exercise on MuRF-1 mRNA expression are influenced by factors such as exercise order, intensity, contraction mode, age, sex, and fitness level. Conclusions: This systematic review shows that MuRF-1 mRNA expression is significantly modulated by physical exercise in humans and is sensitive to different exercise modalities. These findings suggest that this key protein involved in muscle protein breakdown and turnover is essential for exercise-induced adaptations, contributing to skeletal muscle recovery and remodeling after exercise.