In this paper, a method that combines image analysis techniques, such as segmentation and registration, is proposed for an advanced and progressive evaluation of thermograms. The method is applied for the prevention of muscle injury in high-performance athletes, in collaboration with a Brazilian professional soccer club. The goal is to produce information on spatio-temporal variations of thermograms favoring the investigation of the athletes’ conditions along the competition. The proposed method improves on current practice by providing a means for automatically detecting adaptive body-shaped regions of interest, instead of the manual selection of simple shapes. Specifically, our approach combines the optimization features in Otsu’s method with a correction factor and post-processing techniques, enhancing thermal-image segmentation when compared to other methods. Additional contributions resulting from the combination of the segmentation and registration steps of our approach are the progressive analyses of thermograms in a unique spatial coordinate system and the accurate extraction of measurements and isotherms.

Introduction: Muscular strength is an essential capacity for soccer players; however, the profile of this capacity has not yet been clearly established in young players. Objective: To compare muscular strength performance in the countermovement jump (CMJ) task and the presence of lower limb asymmetry among soccer athletes of the under 15 (U15), under 17 (U17) and under 20 (U20) categories, and between two teams of different competitive levels. Methods: One hundred and fifty one young soccer players of three different categories (U15, U17 and U20) from two teams in the Brazilian first and second divisions performed six vertical jumps in a system of two force plates. Ground reaction force (GRF) was used to calculate jump height and to obtain the variables Peak force (FMAX), Impulse (I) and Peak power (PMAX) with regard to body mass and the respective asymmetry values. Results: No differences were found in the performance and asymmetry variable between the categories (Jump height: p=0.23; FMAX: p=0.15; I: p=0.11; PMAX: p=0.32; FMAX asymmetry: p=0.21; I asymmetry: p=0.58; PMAX asymmetry: p=0.58). The first division club had higher muscle strength and asymmetry values than the second division club (Jump height: p<0.01; I: p<0.01; PMAX: p<0.01; FMAX asymmetry: p<0.01; I asymmetry: p<0.01; PMAX asymmetry: p<0.01), except for FMAX (p=0.63). No variable had an interaction effect (club x category). Conclusion: As categories progress, jump height, relative I, PMAX and FMAX values and their respective asymmetries are stable. The asymmetry and strength performance of the first division club were higher than that of the second division club, except for FMAX, indicating that the competitive level may influence strength performance and the development of asymmetry. Level of Evidence II; Diagnostic study – Investigating a diagnostic test.

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.

Genetic factors demonstrate influence on the components of athletic performance, but also on the activation and resolution of inflammation, muscle tissue immunity and other phenotypes. Titin (TTN) is a giant sarcomere protein that plays an essential role in muscle contraction with actin and myosin filaments. Its polymorphism may contribute to the inter-individual variation in the structural and functional properties of the muscle and tendon and its response to mechanical load, which may imply susceptibility to muscle injury. The identification of genes that may influence the levels of molecules involved in the sarcomeric structure can help to elucidate the factors and mechanisms related to muscle damage and consequent inflammatory process. The aim of the present study was to investigate the association of a TTN polymorphism, TTN-AS1 (RS1001238), with inflammation-related phenotypes in soccer players after a training session with predominance of eccentric actions. The sample consisted of 47 under-20 men's soccer players belonging to clubs in the first division of Brazilian soccer. Blood samples were collected before, 24, and 48 hours after the training session to evaluate the inflammatory responses (hematological neutrophil analysis, high sensitivity quantitative protein (CRP), tumor necrosis factor (TNFα)), muscle damage (creatine kinase (CK)), and insulin-like growth factor 1 (IGF-1). It was observed that individuals with the CC genotype for the TTN-AS1 Polymorphism (RS1001238) showed greater inflammatory responses (p<0.01) in relation to the TT and TC genotypes, with greater damage verified by CK (p<0.01) concentrations, TTN-AS1 (RS1001238) phenotypes and its possible structural alterations in skeletal striated muscle sarcomeres.