Muscle injuries are among the main reasons for medical leavings of soccer athletes, being a major concern within professional teams and their prevention associated with sport success. Several factors are associated with a greater predisposition to injury, and genetic background is increasingly being investigated. The aim of this study was to analyze whether ACTN3 R577X and ACE I/D polymorphisms are predictors of the incidence and severity of muscle injury in professional soccer athletes from Brazil, individually and in association. Eighty-three professional athletes from the first and second divisions of the Brazilian Championship were evaluated regarding the polymorphisms through blood samples. Nighty-nine muscle injuries were identified during the seasons of 2018, 2019 and 2020 and categorized according to severity. ACTN3 XX individuals had a higher frequency of severe injuries compared to the RX and RR genotypes (p = 0.001), and in the dominant model (compared to RX+RR), with p < 0.001. The trend p-value test showed an increased number of injuries/season following the order XX > RX > RR (p = 0.045). Those with the ACE II genotype had almost 2 fold the number of injuries per season compared to those with the ID+DD genotypes (p = 0.03). Logistic regression showed that the polymorphisms are predictors of the development of severe injury (ACTN3 R577X model with p = 0.004, R2: 0.259; ACE I/D model with p = 0.045, R2: 0.163), where ACTN3 XX individuals were more likely to suffer from severe injury (OR: 5.141, 95% CI: 1.472–17.961, p = 0.010). The combination of the ACTN3 577X allele and the ACE II genotype showed an increased number of injuries per season, enhanced by 100% (1.682 injuries/season versus 0.868 injuries/season, p = 0.016). Our findings suggest that both polymorphisms ACTN3 R577X and ACE I/D (and their interaction) are associated with the susceptibility and severity of non-contact muscle injury in soccer players.

Purpose. the aim of the study was to examine the differences of the anaerobic speed reserve (ASr) in soccer players according to the playing positions (defenders, midfielders, and forwards). Methods. Overall, 120 elite-level national Brazilian soccer players (46 defenders, 45 midfielders, and 29 forwards) performed a field incremental test to estimate maximal aerobic speed (MAS) and a 30-m sprint to determine maximal sprinting speed (MSS). the difference between MAS and MSS was used to estimate ASr. Players were classified by position and by MAS and MSS performance. For each playing position, they were ranked and divided into higher and lower MSS (MSS-H and MSS-L, respectively) and MAS (MAS-H and MAS-L, respectively) groups. the players' ASr was compared among these groups. Results. the comparison of ASr within playing position showed no difference among defenders, midfielders, or forwards. In addition, a higher ASr was found for the fastest players (MSS-H) in all playing positions as compared with their MSS-L counterparts. When ASr was compared between MASH and MAS-L, a significant difference (p < 0.05) was observed. A high correlation was noted between ASr and MSS (r = 0.72; p < 0.001) and between ASr and MAS (r =-0.63; p < 0.001). Conclusions. MSS is the main index that determines the magnitude of ASr, which should be considered when characterizing the soccer players' running speed profile. However, no difference was found when the playing positions were compared, indicating similar characteristics of the running profile in a large sample of soccer players.

O objetivo do estudo foi verificar os sintomas de distúrbios osteomusculares - SDO em professores de academias e sua associação com jornada de trabalho, sexo e função exercida. O estudo foi do tipo transversal e contou com a participação de 54 professores. Os SDO foram verificados através do Questionário Nórdico de Sintomas Osteomusculares. A média de idade foi de 31,2 (± 6,9) anos. Verificou-se que 41 (75,9%) professores relataram SDO em pelo menos uma região anatômica nos últimos 12 meses e 25 (46,3%) nos últimos sete dias. Trabalhar mais de oito horas/dia e exercer duas ou mais funções apresentaram relação positiva com SDO na "parte inferior das costas". Apesar deste profissional apregoar a saúde e o bem-estar físico, a prevalência de SDO foi alta e semelhante com a de outras profissões.

No abstract