Injury surveillance in male professional football; is medical staff reporting complete and accurate?

Since the 2000 season, an injury surveillance system has been established to monitor injury risk and injury patterns in the Norwegian professional football league. The aim of this study was to assess the accuracy of routine injury registration performed by medical staff in professional football. The team medical staff completed injury registration forms on a monthly basis throughout the 2007 season (January–October). Players were interviewed at the end of the season (October/November) about all injuries that occurred from July through September. Thirteen of fourteen teams, 296 of 310 A‐squad players were interviewed. An injury was recorded when a player was unable to take fully part in football training or match the day after injury. A total of 174 injuries were registered, 123 acute injuries and 51 overuse injuries. Of these, 141 were reported by medical staff and 122 by players. Eighty‐nine injuries (51%) were registered using both methods, 52 (30%) by medical staff only and 33 (19%) by player interviews only. Prospective injury surveillance by team medical staff in Norwegian male professional football underestimates the incidence of time‐loss injuries by at least one‐fifth.     

Stress fractures in elite male football players

The objective was to investigate the incidence, type and distribution of stress fractures in professional male football players. Fifty‐four football teams, comprising 2379 players, were followed prospectively for 189 team seasons during the years 2001–2009. Team medical staff recorded individual player exposure and time‐loss injuries. The first team squads of 24 clubs selected by UEFA as belonging to the 50 best European teams, 15 teams of the Swedish Super League and 15 teams playing their home matches on artificial turf pitches were included. In total, 51 stress fractures occurred during 1 180 000 h of exposure, giving an injury incidence of 0.04 injuries/1000 h. A team of 25 players can therefore expect one stress fracture every third season. All fractures affected the lower extremities and 78% the fifth metatarsal bone. Stress fractures to the fifth metatarsal bone, tibia or pelvis caused absences of 3–5 months. Twenty‐nine percent of the stress fractures were re‐injuries. Players that sustained stress fractures were significantly younger than those that did not. Stress fractures are rare in men's professional football but cause long absences. Younger age and intensive pre‐season training appear to be risk factors.     

Comparison of injuries sustained on artificial turf and grass by male and female elite football players

The objective of this study was to compare incidences and patterns of injury for female and male elite teams when playing football on artificial turf and grass. Twenty teams (15 male, 5 female) playing home matches on third‐generation artificial turf were followed prospectively; their injury risk when playing on artificial turf pitches was compared with the risk when playing on grass. Individual exposure, injuries (time loss) and injury severity were recorded by the team medical staff. In total, 2105 injuries were recorded during 246 000 h of exposure to football. Seventy‐one percent of the injuries were traumatic and 29% overuse injuries. There were no significant differences in the nature of overuse injuries recorded on artificial turf and grass for either men or women. The incidence (injuries/1000 player‐hours) of acute (traumatic) injuries did not differ significantly between artificial turf and grass, for men (match 22.4 v 21.7; RR 1.0 (95% CI 0.9–1.2); training 3.5 v 3.5; RR 1.0 (0.8–1.2)) or women [match 14.9 v 12.5; RR 1.2 (0.8–1.8); training 2.9 v 2.8; RR 1.0 (0.6–1.7)]. During matches, men were less likely to sustain a quadriceps strain (P=0.031) and more likely to sustain an ankle sprain (P=0.040) on artificial turf.     

The 11+ Kids warm-up programme to prevent injuries in young Iranian male high-level football (soccer) players: A cluster-randomised controlled trial

ObjectiveTo assess the effectiveness of the 11+ Kids warm-up programme regarding injury reduction in male high-level children’s football players.DesignCluster-randomised controlled trial.MethodMale youth football teams of Iran’s high-level football schools were invited to participate. Inclusion criteria were: teams are competing in the highest league of their province; players are between 7 and 14 years old; regular training takes place at least twice per week. Teams were excluded if they used an injury prevention measure.Participating clubs were randomised to an intervention (INT, N = 20 teams) and a control group (CON, N = 22 teams), stratified by the number of teams and the age group. The groups were blinded against each other. The follow-up period was one season (9 months). INT replaced their warm-up by 11+ Kids. CON performed a standard warm-up programme. The primary outcome was the injury incidence density (injuries per 1000 h of football exposure), compared between groups by incidence rate ratios (RR).ResultsIn total, 64,047 h of football exposure of 962 players (INT = 443 players, 31,934 h of football, CON = 519 players, 32,113 h of football) were recorded. During the study, 90 (INT = 30; CON = 60) injuries occurred. The overall injury incidence density in INT was reduced by 50% compared to CON (RR 0.50; 95%-CI 0.32, 0.78). No injuries occurred during the execution of the intervention exercises.ConclusionsThe 11+ Kids reduces injuries in high-level children’s football players, thus supporting player health and potentially performance and player development.     

Football injuries during European Championships 2004–2005

The risk of injury in football is high, but few studies have compared men’s and women’s football injuries. The purpose of this prospective study was to analyse the exposure and injury characteristics of European Championships in football and to compare data for men, women and male youth players. The national teams of all 32 countries (672 players) that qualified to the men’s European Championship 2004, the women’s European Championship 2005 and the men’s Under-19 European Championship 2005 were studied. Individual training and match exposure was documented during the tournaments as well as time loss injuries. The overall injury incidence was 14 times higher during match play than during training (34.6 vs. 2.4 injuries per 1000 h, P < 0.0001). There were no differences in match and training injury incidences between the championships. Teams eliminated in the women’s championship had a significantly higher match injury incidence compared to teams going to the semi-finals (65.4 vs. 5.0 injuries per 1000 h, P = 0.02). Non-contact mechanisms were ascribed for 41% of the match injuries. One-fifth of all injuries were severe with absence from play longer than 4 weeks. In conclusion, injury incidences during the European Championships studied were very similar and it seems thus that the risk of injury in international football is at least not higher in women than in men. The teams eliminated in the women’s championship had a significantly higher match injury incidence than the teams going to the final stage. Finally, the high frequency of non-contact injury is worrying from a prevention perspective and should be addressed in future studies.     

Gradual increase in the risk of match injury in Norwegian male professional football: A 6‐year prospective study

The aim of this study was to monitor injury incidence and pattern in Norwegian male professional football over six consecutive seasons and compare the risk of injury between the preseason and competitive season. All time loss injuries were recorded by the medical staff of each club. In total, 2365 injuries were recorded. The incidence of acute injuries was 15.9/1000 match hours [95% confidence interval (CI): 14.9–16.8], 1.9/1000 training hours (95% CI: 1.7–2.0), and 1.4 (95% CI: 1.3–1.5) overuse injuries/1000 h. A linear regression model found an annual increase of 1.06 acute match injuries/1000 h (95% CI: 0.40–1.73), corresponding to a total increase of 49% during the 6‐year study period. When accounting for interteam variation and clustering effects using a general estimating equation model, the increase in injury incidence was 0.92 (95% CI: ?0.11–1.95, P = 0.083). No difference in the risk of acute match injuries (rate ratio (RR): 0.86, 95% CI: 0.73–1.01), acute training injuries (RR: 1.16, 95% CI: 0.99–1.36), or overuse injuries (RR: 1.04, 95% CI: 0.89–1.21) was observed between the preseason and competitive season. In conclusion, the overall risk of acute match injuries in Norwegian male professional football increased by 49% during the study period, although this increase was not fully consistent across teams. We detected no change in the risk of training and overuse injuries or any difference between the preseason and competitive season.     

UEFA Champions League study: a prospective study of injuries in professional football during the 2001-2002 season

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) v 24.0 (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 (67 v 36; 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.     

Previous injury as a risk factor for injury in elite football: a prospective study over two consecutive seasons

Background

Previous injury is often proposed to be a risk factor for football injury, but most studies rely on players reporting their own medical history and are thus potentially subject to recall bias. Little is known about the natural variation in injury pattern between seasons.

Objectives

To study whether prospectively recorded injuries during one season are associated with injuries sustained during the following season, and to compare injury risk and injury pattern between consecutive seasons.

Methods

The medical staffs of 12 elite Swedish male football teams prospectively recorded individual exposure and time loss injuries over two full consecutive seasons (2001 and 2002). A multivariate model was used to determine the relation between previous injury, anthropometric data, and the risk of injury.

Results

The training and match injury incidences were similar between seasons (5.1 v 5.3 injuries/1000 training hours and 25.9 v 22.7/1000 match hours), but analysis of injury severity and injury patterns showed variations between seasons. Players who were injured in the 2001 season were at greater risk of any injury in the following season compared with non‐injured players (hazard ratio 2.7; 95% confidence interval 1.7 to 4.3, p<0.0001). Players with a previous hamstring injury, groin injury, and knee joint trauma were two to three times more likely to suffer an identical injury in the following season, whereas no such relation was found for ankle sprain. Age was not associated with an increased injury risk.

Conclusions

This study confirmed previous results showing that previous injury is an important risk factor for football injury. Overall injury incidences were similar between consecutive seasons, indicating that an injury surveillance study covering one full season can provide a reasonable overview of the injury problem among elite football players in a specific environment. However, a prolonged study period is recommended for analyses of specific injury patterns.     

Self‐reported previous knee injury and low knee function increase knee injury risk in adolescent female football

Knee injuries are common in adolescent female football. Self‐reported previous knee injury and low Knee injury and Osteoarthritis Outcome Score (KOOS) are proposed to predict future knee injuries, but evidence regarding this in adolescent female football is scarce. The aim of this study was to investigate self‐reported previous knee injury and low KOOS subscale score as risk factors for future knee injuries in adolescent female football. A sample of 326 adolescent female football players, aged 15–18, without knee injury at baseline, were included. Data on self‐reported previous knee injury and KOOS questionnaires were collected at baseline. Time‐loss knee injuries and football exposures were reported weekly by answers to standardized text‐message questions, followed by injury telephone interviews. A priori, self‐reported previous knee injury and low KOOS subscale scores (< 80 points) were chosen as independent variables in the risk factor analyses. The study showed that self‐reported previous knee injury significantly increased the risk of time‐loss knee injury [relative risk (RR): 3.65, 95% confidence (CI) 1.73–7.68; P < 0.001]. Risk of time‐loss knee injury was also significantly increased in players with low KOOS subscale scores (< 80 points) in Activities of Daily Living (RR: 5.0), Sport/Recreational (RR: 2.2) and Quality of Life (RR: 3.0) (P < 0.05). In conclusion, self‐reported previous knee injury and low scores in three KOOS subscales significantly increase the risk of future time‐loss knee injury in adolescent female football.     

Injuries in youth amateur soccer and rugby players--comparison of incidence and characteristics

OBJECTIVES: In reviewing the literature on sports injuries, few studies could be found in which exposure related incidences of injury in different types of sport were compared. These studies indicated that ice hockey, handball, basketball, soccer, and rugby are popular team sports with a relatively high risk of injury. The aim of the study was to compare the characteristics and incidence of injuries in male youth amateur soccer and rugby players. METHODS: This prospective cohort study comprised an initial baseline examination to ascertain the characteristics of the players and their level of performance, and a one season observation period during which a physician visited the team weekly and documented all occurring injuries. Twelve soccer and 10 rugby school teams with male amateur players aged 14-18 years were selected for the study. 145 soccer and 123 rugby players could be followed up over one season. RESULTS: Comparison of the incidence of soccer and rugby injuries indicated that rugby union football was associated with a significantly higher rate of injury than soccer. The differences were pronounced for contact injuries, injuries of the head, neck, shoulder, and upper extremity, as well as for concussion, fractures, dislocations, and strains. Rugby players incurred 1.5 times more overuse and training injuries in relation to exposure time, and 2.7 times more match injuries than soccer players. Three rugby players but no soccer players had to stop their participation in sport because of severe injury. CONCLUSION: The incidence of injury in New Zealand school teams playing soccer or rugby union is high, probably in part because of the low ratio of hours spent in training relative to hours spent playing matches. The development and implementation of preventive interventions to reduce the rate and severity of injury is recommended.     

Exposure and injury risk in Swedish elite football: a comparison between seasons 1982 and 2001

The long-term development of injury risk in Swedish male elite football was studied. Two prospective cohort studies from seasons 1982 and 2001 were compared with respect to exposure to football, injury incidence and injury severity. The mean number of training sessions during the season had increased by 68% between 1982 and 2001 (142 vs. 238, P<0.001), whereas teams played more matches in 1982 (49 vs. 41, P=0.02). The total exposure to football had increased by 27%. Three out of four players incurred an injury in both seasons. In 2001, players suffered more training injuries due to an increased training exposure. Accounting for risk exposure, there was no difference in injury incidence or severity between the two seasons. The incidence was 8.3 injuries/1000 h of total exposure (4.6 in training and 20.6 in matches) in 1982, compared to 7.8/1000 h-1 (5.2 in training and 25.9 in matches) in 2001. Major injuries accounted for 9% of all injuries, corresponding to an incidence of 0.8/1000 h of football, in both seasons. A trend from semi-professionalism to full professionalism in Swedish elite football was seen during the last two decades. The injury risk did not change over the same period.     

Preventing injuries in female youth football--a cluster-randomized controlled trial

A set of exercises--the "11"--have been selected to prevent football injuries. The purpose of this cluster-randomized controlled trial was to investigate the effect of the "11" on injury risk in female youth football. Teams were randomized to an intervention (n=59 teams, 1091 players) or a control group (n=54 teams, 1001 players). The intervention group was taught the "11," exercises for core stability, lower extremity strength, neuromuscular control and agility, to be used as a 15-min warm-up program for football training over an 8-month season. A total of 396 players (20%) sustained 483 injuries. No difference was observed in the overall injury rate between the intervention (3.6 injuries/1000 h, confidence interval (CI) 3.2-4.1) and control group (3.7, CI 3.2-4.1; RR=1.0, CI 0.8-1.2; P=0.94) nor in the incidence for any type of injury. During the first 4 months of the season, the training program was used during 60% of the football training sessions, but only 14 out of 58 intervention teams completed more than 20 prevention training sessions. In conclusion, we observed no effect of the injury prevention program on the injury rate, most likely because the compliance with the program was low.     

Injuries among male and female elite football players

All 12 female football clubs (228 players) and 11 of 14 male clubs (239 players) in the Swedish premier league were followed prospectively during the 2005 season. Individual exposure (playing time), injuries (time loss), and injury severity (days lost due to injury) were recorded by the team medical staffs. Injury incidence was higher for male players during both training (4.7 vs 3.8 injuries/1000 h, P=0.018) and match play (28.1 vs 16.1, P<0.001). However, no difference was found in the incidence of severe injury (absence >4 weeks) (0.7/1000 h in both groups). The thigh, especially the hamstrings, was the overall most commonly injured region in both sexes, while the hip/groin was more commonly injured in male players and the knee in female players. Knee ligament injuries accounted for 31% and 37% of the total time lost from football for male and female players, respectively. In conclusion, male elite players had a higher injury incidence than their female counterparts although no difference was observed in the incidence of moderate to severe injury. We recommend that preventive measures should be focused on hamstring and knee ligament injury in order to reduce the overall injury burden.     

Upper extremity injuries in male elite football players

Purpose

To investigate the epidemiology of upper extremity injuries in male elite football players and to describe their characteristics, incidence and lay-off times.

Methods

Between 2001 and 2011, 57 male European elite football teams (2,914 players and 6,215 player seasons) were followed prospectively. Time-loss injuries and exposure to training and matches were recorded on individual basis.

Results

In total, 11,750 injuries were recorded, 355 (3 %) of those affected the upper extremities giving an incidence of 0.23 injuries/1,000 h of football. The incidence in match play was almost 7 times higher than in training (0.83 vs. 0.12 injuries/1,000 h, rate ratio 6.7, 95 % confidence interval 5.5–8.3). As much as 32 % of traumatic match injuries occurred as a result of foul play situations. Goalkeepers had a significantly higher incidence of upper extremity injuries compared to outfield players (0.80 vs. 0.16 injuries/1,000 h, rate ratio 5.0, 95 % confidence interval 4.0–6.2). The average absence due to an upper extremity injury was 23 ± 34 days.

Conclusions

Upper extremity injuries are uncommon among male elite football players. Goalkeepers, however, are prone to upper extremity injury, with a five times higher incidence compared to outfield players.

Level of evidence

II.     

Injuries in Swedish elite football--a prospective study on injury definitions, risk for injury and injury pattern during 2001

The purpose of this study was to study the risk for injury and injury pattern in Swedish male elite football and to compare two different injury definitions. A prospective cohort study was conducted during 2001 on all 14 teams (310 players) in the Swedish top division. Injuries and individual exposure were recorded. Injury was defined as time-lost injury (715 injuries) and for comparison as tissue injury (765 injuries). No significant difference in the risk for injury between tissue injuries and time-lost injuries was found during matches (27.2 vs. 25.9 injuries per 1000 match hours, P=0.66) or training sessions (5.7 vs. 5.2 injuries per 1000 training hours, P=0.65). The risk for injury during training was significantly higher during the pre-season compared with the competitive season (P=0.01). Thigh strain was the single most common injury (14%). Knee sprain was the most common major injury (absence >4 weeks). Overuse injuries and re-injuries were frequent and constituted 37% and 22% of all injuries. Re-injuries caused significantly longer absence than their corresponding initial injuries (P=0.02). The risk for re-injury (P=0.02) and overuse injury (P<0.01) was significantly higher during the pre-season compared with the competitive season.     

Modeling the impact of players’ workload on the injury‐burden of English Premier League football clubs

The loss of players through injury is known to affect team performance in many sports; it is important, therefore, for professional teams to be able to quantify the likely injury‐burden that will be encountered throughout a season. A kinetic model, based on the rates at which match and training injuries are sustained and resolved, a team's squad size and the 2017/2018 season fixture schedule for teams competing in the English Premier League, is used to produce daily forecasts of injury‐burden experienced by a typical team. The incidences and median severities of match (incidence: 26.9 injuries/1000 player‐match hours, 95% CI : 21.5‐33.7; severity: 17.5 days, 95% CI : 13.0‐28.0) and training (incidence: 4.3 injuries/1000 player‐training hours, 95% CI : 3.4‐5.5; severity: 14.0 days, 95% CI : 11.0‐22.0) injuries were determined using data collected from four English Premier League football clubs during the 2016/2017 season. Time‐to‐recovery curves for the match and training injuries sustained in the Premier League closely matched the time‐to‐recovery curves predicted by the kinetic model used in this study. The kinetic model predicted higher match and lower training injury burdens and a higher overall injury burden for successful teams competing in both national and European club competitions compared to teams competing only in national competitions. The model also showed that, in terms of injury‐burden, there were no benefits in adopting a 4‐week mid‐season break during the season: reducing the number of clubs competing in the Premier League would, however, reduce the overall injury burden during a season.     

No effect of a video-based awareness program on the rate of soccer injuries

BACKGROUND: The injury rate in soccer is high, and effective injury prevention methods are needed. PURPOSE: To test the effect of a video-based awareness program on the incidence of acute injuries in soccer. STUDY DESIGN: Randomized control trial; Level of evidence, 1. METHODS: Participants were elite male soccer players from the top 2 divisions in Iceland. Fifteen of 20 teams completed the study: 7 intervention teams (127 players) and 8 control teams (144 players) chosen by random. Just before the start of the 2000 soccer season, the intervention teams were visited with an intervention program. The program included a 15-minute presentation with information on the injury risk of playing elite soccer, typical injuries, and their mechanisms. Then the players worked together in pairs and analyzed video sequences to develop preventive strategies. The 12 video sequences were selected from the previous Icelandic soccer season, representing 3 typical injury mechanisms that accounted for more than half of all incidents recorded. During the season, team physical therapists prospectively recorded all acute injuries, and coaches recorded training exposure on a special form. Injury incidence was compared between groups and between the 1999 and 2000 seasons for teams that participated in both seasons. RESULTS: No difference was observed in injury incidence between the intervention (6.6 +/- 0.7 injuries per 1000 player hours) and control groups (6.6 +/- 0.7 injuries per 1000 player hours). Furthermore, there was no difference in injury location or type. CONCLUSION: The video-based injury awareness program showed no effect on injury rate.     

The association football medical research programme: an audit of injuries in professional football

OBJECTIVES: To undertake a prospective epidemiological study of the injuries sustained in English professional football over two competitive seasons. METHODS: Player injuries were annotated by club medical staff at 91 professional football clubs. A specific injury audit questionnaire was used together with a weekly form that documented each club's current injury status. RESULTS: A total of 6,030 injuries were reported over the two seasons with an average of 1.3 injuries per player per season. The mean (SD) number of days absent for each injury was 24.2 (40.2), with 78% of the injuries leading to a minimum of one competitive match being missed. The injury incidence varied throughout the season, with training injuries peaking during July (p<0.05) and match injuries peaking during August (p<0.05). Competition injuries represented 63% of those reported, significantly (p<0.01) more of these injuries occurring towards the end of both halves. Strains (37%) and sprains (19%) were the major injury types, the lower extremity being the site of 87% of the injuries reported. Most injury mechanisms were classified as being non-contact (58%). Re-injuries accounted for 7% of all injuries, 66% of these being classified as either a strain or a sprain. The severity of re-injuries was greater than the initial injury (p<0.01). CONCLUSIONS: Professional football players are exposed to a high risk of injury and there is a need to investigate ways of reducing this risk. Areas that warrant attention include the training programmes implemented by clubs during various stages of the season, the factors contributing to the pattern of injuries during matches with respect to time, and the rehabilitation protocols employed by clubs.     

Risk factors for noncontact ankle sprains in high school football players: the role of previous ankle sprains and body mass index

BACKGROUND: In a previous study, we noted a possible connection between an athlete's weight and risk of ankle sprain. HYPOTHESIS: A high body mass index and a history of a previous ankle sprain increase the risk of a subsequent noncontact sprain. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: One hundred fifty-two athletes from 4 football teams were observed (2 varsity and 2 junior varsity). Two teams were observed for 3 seasons, and 2 teams were observed for 1 season. Before each season, body mass, height, history of previous ankle sprains, and ankle tape or brace use were recorded. RESULTS: There were 24 ankle sprains, of which 15 were noncontact inversion sprains (11 grade I, 3 grade II, 1 grade III; incidence, 1.08 per 1000 athlete-exposures). Injury incidence was higher in athletes with previous ankle injuries (2.60 vs 0.39; P < .001). Body mass index was also a risk factor (P < .05): injury incidence was 0.52 for players with a normal body mass index, 1.05 for players at risk of overweight, and 2.03 for overweight players. Injury incidence was 0.22 for normal-weight players with no previous ankle sprain compared with 4.27 for overweight players who had a previous sprain. CONCLUSION: An overweight player who had a previous ankle sprain was 19 times more likely to sustain a noncontact ankle sprain than was a normal-weight player with no previous ankle sprain. CLINICAL RELEVANCE: Ankle sprain prevention strategies should be targeted at football players with a high body mass index and a history of previous ankle sprains.