The aim was to investigate the association of injuries with male football player continuity, progression and chances of reaching the First team in an elite academy. Injuries and exposure time were prospectively recorded, following the FIFA guidelines, over 6 seasons (2011-2017) in Under (U)12, U14, U16, U19, 2nd/3rd team and First team players from the same professional football club. Results showed that U19 and 2nd/3rd team players progressing to the next level had a lower injury burden and higher match availability compared to players that did not progress. Injury burden was lower in players progressing from U12 to U14. All players progressing from the 2nd/3rd teams to the First team had a match availability higher than 84% and did not suffer an anterior cruciate ligament (ACL) rupture or an injury requiring over 200 (+200) days to return to play. In U19 and 2nd/3rd team players, injuries requiring +100 and +200 days to return to play, ACL ruptures and groin pain, but not hamstring and ankle ligament injuries, were associated with lower odds of continuing in the academy each season. In conclusion, injuries were negatively associated with player progression, and injury prevention and return-to-play strategies should be a priority for football academies.

Monocarboxylate transporters (MCTs) have been proposed as important mediators of the exchange between lactate (La⁻) producer and La⁻ recipient (consumer) cells. Previous studies have suggested that the MCT1 A1470T genotype could be related to different physical performance phenotypes. This study followed the guidelines for Strengthening the Reporting of Genetic Association Studies (STREGA) and aimed to evaluate the distribution of the MCT1 polymorphism rs1049434 in endurance-trained athletes compared to the untrained population. Moreover, this study explored the potential influence of the polymorphism alleles phenotypes on high-intensity exercise performance. In a cross-sectional study fashion, a total of 85 triathletes from northern Spain were genotyped for MCT1 rs1049434 and compared to a control group of 107 healthy male participants (1000 Genomes Research Study for Iberian Populations in Spain). All athletes performed a 30 s Wingate all-out test (WAnT) on a cycle ergometer. Peak and mean power (absolute and relative) were measured. After verification of the Hardy–Weinberg equilibrium, the findings indicated that the MCT1 TT genotype was overrepresented in triathletes in comparison to the genotypic frequency of the general Spanish population. No significant associations were found between any MCT1 genotype and peak or mean power performance in the WAnT. Further studies are required to understand the relationship among MCT1 A1470T polymorphism, endurance-trained athletes, and high-intensity performance.

The effect of birthplace (the place where a player is born and grows up) is one of the key variables associated with soccer player development and achievement. However, recent studies have questioned the influence of contextual variables on selection and promotion processes related to birthplace. The main purposes of this study were: (1) establish whether there is a difference between the birthplace and sporting growth according to the stages of entry into the academy, (2) to evaluate the influence of geographical and contextual variables on sporting development, and (3) assess the chances of making a professional team debut. Applied logistic regression was used in order to analyse the birthplace and growth of 1411 male soccer players, of which 40.1% are incorporated in the U-12 category from a Spanish First division club, and the results showed a statistically significant association between a change from one’s birthplace to the place of sporting growth and later success (79%). Key contextual variables such as number of inhabitants, population density, proximity to sports facilities, average household income and presence of sports clubs have been considered. The analysis of the contextual variables revealed that there was a positive relationship between certain variables, like a higher population, and being selected for the academy (p < 0.01; r = 0.28). Finally, the findings showed that players who experienced a geographical transition were 38% more likely to make a professional debut. The importance of considering the place of sporting growth when analysing the “birthplace effect” has therefore been demonstrated.