Background Current knowledge on anterior cruciate ligament (ACL) injury mechanisms in male football players is limited. Aim To describe ACL injury mechanisms in male professional football players using systematic video analysis. Methods We assessed videos from 39 complete ACL tears recorded via prospective professional football injury surveillance between 2001 and 2011. Five analysts independently reviewed all videos to estimate the time of initial foot contact with the ground and the time of ACL tear. We then analysed all videos according to a structured format describing the injury circumstances and lower limb joint biomechanics. Results Twenty-five injuries were non-contact, eight indirect contact and six direct contact injuries. We identified three main categories of non-contact and indirect contact injury situations: (1) pressing (n=11), (2) re-gaining balance after kicking (n=5) and (3) landing after heading (n=5). The fourth main injury situation was direct contact with the injured leg or knee (n=6). Knee valgus was frequently seen in the main categories of non-contact and indirect contact playing situations (n=11), but a dynamic valgus collapse was infrequent (n=3). This was in contrast to the tackling-induced direct contact situations where a knee valgus collapse occurred in all cases (n=3). Conclusions Eighty-five per cent of the ACL injuries in male professional football players resulted from non-contact or indirect contact mechanisms. The most common playing situation leading to injury was pressing followed by kicking and heading. Knee valgus was frequently seen regardless of the playing situation, but a dynamic valgus collapse was rare.

Objective To evaluate the effectiveness of neuromuscular training in reducing the rate of acute knee injury in adolescent female football players.Design Stratified cluster randomised controlled trial with clubs as the unit of randomisation.Setting 230 Swedish football clubs (121 in the intervention group, 109 in the control group) were followed for one season (2009, seven months).Participants 4564 players aged 12-17 years (2479 in the intervention group, 2085 in the control group) completed the study.Intervention 15 minute neuromuscular warm-up programme (targeting core stability, balance, and proper knee alignment) to be carried out twice a week throughout the season.Main outcome measures The primary outcome was rate of anterior cruciate ligament injury; secondary outcomes were rates of severe knee injury (>4 weeks’ absence) and any acute knee injury.Results Seven players (0.28%) in the intervention group, and 14 (0.67%) in the control group had an anterior cruciate ligament injury. By Cox regression analysis according to intention to treat, a 64% reduction in the rate of anterior cruciate ligament injury was seen in the intervention group (rate ratio 0.36, 95% confidence interval 0.15 to 0.85). The absolute rate difference was −0.07 (95% confidence interval −0.13 to 0.001) per 1000 playing hours in favour of the intervention group. No significant rate reductions were seen for secondary outcomes.Conclusions A neuromuscular warm-up programme significantly reduced the rate of anterior cruciate ligament injury in adolescent female football players. However, the absolute rate difference did not reach statistical significance, possibly owing to the small number of events.Trial registration Clinical trials NCT00894595.

Objectives To: (1) describe hamstring injury incidence and burden in male professional football players over 21 seasons (2001/02 to 2021/22); (2) analyse the time-trends of hamstring muscle injuries over the most recent eight seasons (2014/15 to 2021/22); and (3) describe hamstring injury location, mechanism and recurrence rate. Methods 3909 players from 54 teams (in 20 European countries) from 2001/02 to 2021/22 (21 consecutive seasons) were included. Team medical staff recorded individual player exposure and time-loss injuries. Time-trend analyses were performed with Poisson regression using generalised linear models. Results 2636 hamstring injuries represented 19% of all reported injuries, with the proportion of all injuries increasing from 12% during the first season to 24% in the most recent season. During that same period, the percentage of all injury absence days caused by hamstring injuries increased from 10% to 20%. Between 2014/15 and 2021/22, training hamstring injury incidence increased (6.7% annually, 95% CI 1.7% to 12.5%) as did burden (9.0% annually, 95% CI 1.2% to 18.3%). During those years, the match hamstring injury incidence also increased (3.9% annually, 95% CI 0.1% to 7.9%) and with the same trend (not statistically significant) for match hamstring injury burden (6.2% annually, 95% CI −0.5% to 15.0%). Conclusions Hamstring injury proportions—in number of injuries and total absence days—doubled during the 21-year period of study. During the last eight seasons, hamstring injury rates have increased both in training and match play.

Background:No previous study on adult football involving several different countries has investigated the incidence and pattern of injuries at the highest club competitive level.Objective:To investigate the risk exposure, risk of injury, and injury pattern of footballers involved in UEFA Champions League and international matches during a full football season.Method:Eleven top clubs (266 players) in five European countries were followed prospectively throughout the season of 2001–2002. Time-lost injuries and individual exposure times were recorded during all club and national team training sessions and matches.Results:A total of 658 injuries were recorded. The mean (SD) injury incidence was 9.4 (3.2) injuries per 1000 hours (30.5 (11.0) injuries per 1000 match hours and 5.8 (2.1) injuries per 1000 training hours). The risk of match injury was significantly higher in the English and Dutch teams than in the teams from France, Italy, and Spain (41.8 (3.3)v24.0 (7.9) injuries per 1000 hours; p = 0.008). Major injuries (absence >4 weeks) constituted 15% of all injuries, and the risk of major injury was also significantly higher among the English and Dutch teams (p = 0.04). National team players had a higher match exposure, with a tendency towards a lower training injury incidence than the rest of the players (p = 0.051). Thigh strain was the most common injury (16%), with posterior strains being significantly more common than anterior ones (67v36; p<0.0001).Conclusions:The risk of injury in European professional football is high. The most common injury is the thigh strain typically involving the hamstrings. The results suggest that regional differences may influence injury epidemiology and traumatology, but the factors involved are unclear. National team players have a higher match exposure, but no higher risk of injury than other top level players.