Håkan Bengtsson

Objectives: Our aim was to describe the absence days caused by the 30 most frequent injury diagnoses in elite European women’s club football. Methods: Members of the medical staff in football clubs participating in the Union of European Football Associations (UEFA) Women’s Elite Club Injury Study (WECIS) reported injury occurrences from a total of 72 team-seasons. Injury absence was defined as the number of days between injury occurrence and when the injured player was allowed to return to full participation by the medical team. Results: In total, 2 390 injuries were registered and included in the study. Sixty-six per cent of these injuries were included among the 30 most common injury diagnoses. Most of the injuries included among the 30 most common were mild leading to a median absence of 7 days or less in 397 cases (23%) or moderate leading to a median absence of 7–28 days in 1177 cases (69%). Severe injuries accounted for a median absence of ≥28 days in 140 cases (8%) were less common and included only four diagnoses, all related to knee injuries. These four diagnoses, however, caused 35% of all absence during the study period. Conclusion: Most of the time lost due to injuries in elite European women’s football teams results from moderate and severe injuries. This article provides guidelines for expected time-loss for the most common injury types in women’s professional football and will aid clinicians to make more accurate estimations of when players can be expected to return to participation following injuries.

Objectives: To compare injury incidences between the 2022/23 season and the preceding five seasons, and between World Cup players and non-World Cup players during the 2022/23 season. Methods: During the 2022/23 season, 29 teams participated in the Union of European Football Associations Elite Club Injury Study and reported football exposures and injuries prospectively. Injury incidence was compared with that of the five preceding seasons for the full season and for periods before and after the Fédération Internationale de Football Association World Cup 2022. In addition, World Cup players were compared with non-World Cup players. Incidences were compared using rate ratio (RR) with 95% CI. Results: Injury incidences during the 2022/23 season were similar to previous seasons except for training incidence which, due to a significantly lower incidence in the 2017/18 season compared with all other seasons, was higher during the full season (RR 1.10, 95% CI 1.00 to 1.21) and in the period before the World Cup (RR 1.17, 95% CI 1.02 to 1.35). World Cup players had similar injury incidences before and after the tournament (training incidence; RR 0.95, 95% CI 0.65 to 1.38, match incidence; RR 1.15, 95% CI 0.87 to 1.52) but a significantly lower match incidence than non-World Cup players before the tournament (RR 0.84, 95% CI 0.71 to 1.00). Conclusions: No major changes in injury incidences were observed during the 2022/23 season compared with previous seasons. World Cup players experienced similar injury incidences before and after the tournament, and had a lower match injury incidence before the tournament compared with non-World Cup players.

Objective Injuries in women’s football (soccer) have scarcely been investigated, and no study has been conducted in the highest competitive level involving club teams from different countries. Our aim was to investigate the time-loss injury epidemiology and characteristics among women’s elite football players over four seasons. Methods 596 players from 15 elite women’s teams in Europe were studied prospectively during the 2018/2019 to 2021/2022 seasons (44 team seasons). Medical staff recorded individual player exposure and time-loss injuries. Injury incidence was calculated as the number of injuries per 1000 playing hours and injury burden as the number of days lost per 1000 hours. Results 1527 injuries were recorded in 463 players with an injury incidence of 6.7 (95% CI 6.4 to 7.0) injuries per 1000 hours and a nearly fourfold higher incidence during match play compared with training (18.4, 95% CI 16.9 to 19.9 vs 4.8, 95% CI 4.5 to 5.1; rate ratio 3.8, 95% CI 3.5 to 4.2). Thigh muscle injuries (hamstrings 12%, 188/1527, and quadriceps 11%, 171/1527) were the most frequent injury, while anterior cruciate ligament (ACL) injury had the highest burden (38.0 days lost per 1000 hours, IQR 29.2–52.1) with median days lost of 292 (IQR 246–334) days. Concussions constituted 3% (47/1527) of all injuries, with more than half of them (55%, 26/47) due to ball-related impact. Conclusion An elite women’s football team can expect approximately 35 time-loss injuries per season. Thigh muscle injury was the most common injury and ACL injury had the highest injury burden.

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: Studies on football and the coronavirus disease 2019 (COVID-19) have mainly focused on the lockdown consequences for player fitness, the resumption of football training, and how to safely restart the league play, but injury data are scarce. Objective: To describe the injury incidence and injury burden in men’s professional football teams during the pandemic year of 2020. Methods: Nineteen teams in 12 countries prospectively registered data on player-exposure and time-loss injuries throughout 2020. All major football leagues were paused as a direct response to the pandemic in March 2020 and were thereafter completely cancelled or restarted after a lockdown interval of at least two months. Historical data from 43 teams in the same cohort during the five preceding years (2015–2019) were used as reference. Between-season and within-season comparisons were made for injury incidence (number of injuries per 1000 h) and injury burden (number of absence days per 1000 h) with 95% confidence intervals and interquartile ranges. Results: There was no increased match injury incidence or injury burden following the restart in 2020 compared with other time periods of 2020 and the corresponding periods 2015–2019. There was an increased training injury incidence and injury burden immediately during the lockdown in 2020, and they remained elevated also following the restart, being higher in 2020 compared with 2015–2019, respectively. The injury characteristics during the first months of the new 2020/21 season (August/September–December) were similar between the five teams that cancelled their 2019/20 season in March 2020 and the 14 teams that restarted their season in May/June 2020. Conclusions: There was no increased match injury incidence or injury burden following the COVID-19 lockdown and restart of the football season in 2020, but training injury incidence and injury burden were elevated and higher than in 2015–2019.

Objective To describe the injury epidemiology in professional football in South America and compare it with European professional football. Methods Data about football exposures and injury occurrences were registered in Six teams participating in Copa Libertadores in 2016. These teams’ exposure and injury data were compared with teams participating in the UEFA Elite Club Injury Study during the 2015/2016 and 2016/2017 seasons. Results A total of 271 injuries were reported in the South American cohort representing a training injury incidence of 3.2 (95% CI=2.7 to 3.7) injuries/1000 hours of training exposure and 20.9 (95% CI=17.3 to 25.1) injuries/1000 hours of match exposure. While no differences in muscle injury incidence were observed between South American and European teams, the ligament injury incidence in training among South American teams was significantly higher than European teams (0.6 vs 0.3, RR 1.87, 95% CI 1.21 to 2.87). In addition, a significantly higher proportion of all reported injuries among South American teams than European teams occurred in training. Conclusions A larger proportion of injuries occur in training in South American compared with European professional football. Specifically, ligament injuries in training were more frequent among South American teams.

Background The UEFA Elite Club Injury Study is the largest and longest running injury surveillance programme in football. Objective To analyse the 18-season time trends in injury rates among male professional football players. Methods 3302 players comprising 49 teams (19 countries) were followed from 2000–2001 through 2018–2019. Team medical staff recorded individual player exposure and time-loss injuries. Results A total of 11 820 time-loss injuries were recorded during 1 784 281 hours of exposure. Injury incidence fell gradually during the 18-year study period, 3% per season for both training injuries (95% CI 1% to 4% decrease, p=0.002) and match injuries (95% CI 2% to 3% decrease, pConclusions Over 18 years: (1) injury incidence decreased in training and matches, (2) reinjury rates decreased, and (3) player availability for training and match play increased.

Background It has been hypothesised that injury risk after return to play following an injury absence is influenced by the amount of training completed before return to competition. Aim To analyse if the number of completed training sessions between return to play and the first subsequent match appearance was associated with the odds of injury in men’s professional football. Methods From a cohort study, including 303 637 individual matches, 4805 first match appearances after return to play following moderate to severe injuries (≥8 days absence) were analysed. Rate ratios (RRs) were used to compare injury rates in the first match appearances with the average seasonal match injury rate. Odds ratios (ORs) were used to analyse associations between the number of completed training sessions and general (all injuries), muscle, and non-muscle injury odds. Results Injury rate in the first match after return to play was increased by 87% compared with the average seasonal match injury rate (46.9 vs 25.0/1000 hours, RR=1.87; 95% CI 1.64 to 2.14). The odds of injury dropped 7% with each training session before the first match (OR 0.93; 95% CI 0.87 to 0.98). The same association was found for muscle injuries (OR 0.87; 95% CI 0.79 to 0.95) but not for non-muscle injuries (OR 0.99; 95% CI 0.91 to 1.07). Conclusions Injury rates in the first match after injury are higher than the average seasonal match injury rate, but the propensity for player injury is decreased when players complete more training sessions before their first match.

Objectives The objective was to describe the typical duration of absence following the most common injury diagnoses in professional football. Methods Injuries were registered by medical staff members of football clubs participating in the Union of European Football Association Elite Club Injury Study. Duration of absence due to an injury was defined by the number of days that passed between the date of the injury occurrence and the date when the medical team allowed the player to return to full participation. In total, 22 942 injuries registered during 494 team-seasons were included in the study. Results The 31 most common injury diagnoses constituted a total of 78 % of all reported injuries. Most of these injuries were either mild (leading to a median absence of 7 days or less, 6440 cases = 42%) or moderate (median absence: 7–28 days, 56% = 8518 cases) while only few (2% = 311 cases) were severe (median absence of >28 days). The mean duration of absence from training and competition was significantly different (p < 0.05) between index injuries and re-injuries for six diagnoses (Achilles tendon pain, calf muscle injury, groin adductor pain, hamstring muscle injuries and quadriceps muscle injury) with longer absence following re-injuries for all six diagnoses Conclusions The majority of all time loss due to injuries in professional football stems from injuries with an individual absence of up to 4 weeks. This article can provide guidelines for expected time away from training and competition for the most common injury types as well as for its realistic range.

Aim: To determine the epidemiology of isolated syndesmotic injuries in professional football players. Methods: Data from 15 consecutive seasons of European professional football between 2001 and 2016 contributed to the dataset of this study. Match play and training data from a total of 3677 players from 61 teams across 17 countries have been included. Team medical staff recorded player exposure and time loss injuries. Injury incidence was defined as the number of injuries per 1000 player-hours. Injury burden was defined as number of days absence per 1000 player-hours. Seasonal trends for isolated syndesmotic injury incidence, isolated syndesmotic injury proportion of ankle ligament injuries and isolated syndesmotic injury burden were analysed via linear regression. Results: The isolated syndesmotic injury incidence was 0.05 injuries per 1000 hours of exposure (95% CI 0.04 to 0.06) or one injury per team every three seasons. The injury incidence during match play was 13 times higher compared with during training, 0.21 (95% CI 0.16 to 0.26) and 0.02 (95% CI 0.01 to 0.02), respectively. Out of the 1320 ankle ligament injuries registered during the 15 seasons, 94 (7%) were diagnosed as isolated syndesmotic injuries. An annual increase in injury incidence was observed (R²=0.495, b=0.003, 95% CI 0.001 to 0.004, P=0.003). However, no significant annual change of injury burden was observed (R²=0.033, b=0.032, 95% CI −0.073 to 0.138, P=0.520). Seventy-four per cent of the injuries were contact related, and the mean (±SD) absence following an isolated syndesmotic injury was 39 (±28) days. Conclusions: The incidence of isolated syndesmotic injuries in elite professional European football annually increased between 2001 and 2016.