Risk factors for football injuries in young players aged 7 to 12 years.

Football (soccer) is very popular among children. Little is known about risk factors for football injuries in children. The aim was to analyze potential injury risk factors in 7- to 12-year-old players. We collected prospective data in Switzerland and the Czech Republic over two seasons. Coaches reported exposure of players (in hours), absence, and injury data via an Internet-based registration system. We analyzed time-to-injury data with extended Cox models accounting for correlations on team- and intra-person levels. We analyzed injury risk in relation to age, sex, playing position, preferred foot, and regarding age-independent body height, body mass, and BMI. Further, we analyzed injury risk in relation to playing surface. In total, 6038 player seasons with 395 295 hours of football exposure were recorded and 417 injuries occurred. Injury risk increased by 46% (Hazard Ratio 1.46 [1.35; 1.58]; P < .001) per year of life. Left-footed players had a higher injury risk (Hazard Ratio 1.53 [1.07; 2.19]; P = .02) for training injuries compared to right-footed players. Injury risk was increased in age-adjusted taller players (higher percentile rank). Higher match-training ratios were associated with a lower risk of match injuries. Injury risk was increased on artificial turf (Rate Ratio 1.39 [1.12; 1.73]; P < .001) and lower during indoor sessions (Rate Ratio 0.68 [0.52; 0.88]; P < .001) compared to natural grass. Age is known as a risk factor in older players and was confirmed to be a risk factor in children's football. Playing surface and leg dominance have also been discussed previously as risk factors. Differences in injury risks in relation to sex should be investigated in the future.