Colin W Fuller

Consensus statement on injury definitions and data collection procedures in studies of football (soccer) injuries

Variations in definitions and methodologies have created differences in the results and conclusions obtained from studies of football (soccer) injuries, making interstudy comparisons difficult. Therefore an Injury Consensus Group was established under the auspices of Fédération Internationale de Football Association Medical Assessment and Research Centre. A nominal group consensus model approach was used. A working document on definitions, methodology, and implementation was discussed by the group. Iterative draft statements were prepared and circulated to members of the group for comment before the final consensus statement was produced. Definitions of injury, recurrent injury, severity, and training and match exposures in football together with criteria for classifying injuries in terms of location, type, diagnosis, and causation are proposed. Proforma for recording players’ baseline information, injuries, and training and match exposures are presented. Recommendations are made on how the incidence of match and training injuries should be reported and a checklist of issues and information that should be included in published reports of studies of football injuries is presented.

Incidence, Risk, and Prevention of Hamstring Muscle Injuries in Professional Rugby Union

Background The incidence of hamstring muscle injuries in professional rugby union is high, but evidence-based information on risk factors and injury-prevention strategies in this sport is limited. Purpose To define the incidence, severity, and risk factors associated with hamstring muscle injuries in professional rugby union and to determine whether the use of hamstring strengthening and stretching exercises reduces the incidence and severity of these injuries. Study Design Cohort study (prevention); Level of evidence, 3. Methods Team clinicians reported all hamstring muscle injuries on a weekly basis and provided details of the location, diagnosis, severity, and mechanism of each injury; loss of time from training and match play was used as the definition of an injury. Players’ match and training exposures were recorded on a weekly basis. Results The incidence of hamstring muscle injuries was 0.27 per 1000 player training hours and 5.6 per 1000 player match hours. Injuries, on average, resulted in 17 days of lost time, with recurrent injuries (23%) significantly more severe (25 days lost) than new injuries (14 days lost). Second-row forwards sustained the fewest (2.4 injuries/1000 player hours) and the least severe (7 days lost) match injuries. Running activities accounted for 68% of hamstring muscle injuries, but injuries resulting from kicking were the most severe (36 days lost). Players undertaking Nordic hamstring exercises in addition to conventional stretching and strengthening exercises had lower incidences and severities of injury during training and competition. Conclusion The Nordic hamstring strengthening exercise may reduce the incidence and severity of hamstring muscle injuries sustained during training and competition.

Consensus statement on injury definitions and data collection procedures in studies of football (soccer) injuries.

Variations in definitions and methodologies have created differences in the results and conclusions obtained from studies of football injuries; this has made inter‐study comparisons difficult.

Comparison of the incidence, nature and cause of injuries sustained on grass and new generation artificial turf by male and female football players. Part 1: match injuries

Objective: To compare the incidence, nature, severity and cause of match injuries sustained on grass and new generation artificial turf by male and female footballers. Methods: The National Collegiate Athletic Association Injury Surveillance System was used for a two-season (August to December) prospective study of American college and university football teams (2005 season: men 52 teams, women 64 teams; 2006 season: men 54 teams, women 72 teams). Injury definitions and recording procedures were compliant with the international consensus statement for epidemiological studies of injuries in football. Athletic trainers recorded details of the playing surface and the location, diagnosis, severity and cause of all match injuries. The number of days lost from training and match play was used to define the severity of an injury. Match exposures (player hours) were recorded on a team basis. Results: The overall incidence of match injuries for men was 25.43 injuries/1000 player hours on artificial turf and 23.92 on grass (incidence ratio 1.06; p = 0.46) and for women was 19.15 injuries/1000 player hours on artificial turf and 21.79 on grass (incidence ratio = 0.88; p = 0.16). For men, the mean severity of non-season ending injuries was 7.1 days (median 5) on artificial turf and 8.4 days (median 5) on grass and, for women, 11.2 days (median 5) on artificial turf and 8.9 days (median 5) on grass. Joint (non-bone)/ligament/cartilage and contusion injuries to the lower limbs were the most common general categories of match injury on artificial turf and grass for both male and female players. Most injuries were acute (men: artificial turf 24.60, grass 22.91; p = 0.40; women: artificial turf 18.29, grass 20.64; p = 0.21) and resulted from player-to-player contact (men: artificial turf 14.73, grass 13.34; p = 0.37; women: artificial turf 10.72; grass 11.68; p = 0.50). Conclusions: There were no major differences in the incidence, severity, nature or cause of match injuries sustained on new generation artificial turf and grass by either male or female players.

Contact events in rugby union and their propensity to cause injury

Objective: The objective of this study was to determine the incidence of contact events in professional rugby union matches and to assess their propensity to cause injury. Design: The study was a two-season (2003/2004 and 2005/2006) prospective cohort design. It included 645 professional rugby union players from 13 English Premiership rugby union clubs. The main outcome measures were: incidence of match contact events (events per game); incidence (injuries per 1000 player-hours and per 1000 contact events), risk (days lost per 1000 player-hours and per 1000 contact events) and diagnosis of injury; referee’s decision. Risk factors were player–player contact, position on pitch and period of play. Results: Tackles (221.0 events/game) and rucks (142.5 events/game) were the most common events and mauls (13.6%) and scrums (12.6%) the most penalised. Tackles (701.6 days/1000 player-hours) were responsible for the greatest loss of time but scrums (213.2 days lost/1000 events) and collisions (199.8 days lost/1000 events) presented the highest risk per event. Conclusions: Tackles were the game event responsible for the highest number of injuries and the greatest loss of time in rugby union because they were by far the most common contact event. Collisions were 70% more likely to result in an injury than a tackle and scrums carried a 60% greater risk of injury than a tackle. The relative propensities for contact events to cause injury were rated as: lineout – very low; ruck – low; maul and tackle – average; collision and scrum – high.

The influence of methodological issues on the results and conclusions from epidemiological studies of sports injuries : Illustrative examples

Data obtained from epidemiological studies of sports injuries are an essential requirement for developing injury prevention, treatment and rehabilitation strategies. Although many authors have discussed the strengths and weaknesses of research methods employed in epidemiology, the potential effects that variations in research design and methods of analysis can have on study conclusions have not been clearly illustrated. This article addresses a number of methodological issues and illustrates their potential effects using examples based on injury data obtained from a single, large epidemiological study in professional rugby union. The examples demonstrate that conflicting conclusions can be reached depending on how the data are collected and analysed. The pivotal roles played by injury definition (loss-of-time, missed matches, diagnostic assessment and surgery), recurrent injury definition (clinical judgement and same injury/same location/same season), method of reporting injuries (number, proportions and incidence) and method of calculating incidence (injuries per 1000 player-hours, per 1000 athlete-exposures and per 1000 matches) are highlighted and illustrated. Other examples show that if training and match injuries are combined, the incidence of injury is more likely to reflect the incidence of training injuries but the distributions of injuries are more likely to reflect the distributions of match injuries. An example is presented that demonstrates that the identification of injuries causing the greatest concern within a sport depends on whether the assessment is based on injury incidence, severity or risk. Finally, examples are presented to show that the relationships identified between sports injuries and risk factors may be dependent on whether case-control or cohort study designs are used.Although there are no simple solutions available to resolve the issues raised, the discussion demonstrates the importance, at least within a sport, of reaching consensus agreements on acceptable study designs and methods of data analysis in sports epidemiology.

Injury risks associated with tackling in rugby union

Objective To examine factors associated with tackles in rugby union and to assess their impact on the risk of injury. Design Two-season (2003/2004 and 2005/2006) prospective cohort design with video analysis. Setting 13 English Premiership clubs. Participants 645 players. Main outcome measure RR (95% CI) calculated by comparing the frequency of occurrence of risk factors in a cohort of players injured during tackles with their frequency of occurrence in tackles in general play. Risk factors Playing position; player’s speed, impact force, head position, head/neck flexion and body region struck in the tackle; sequence, direction and type of tackle; and location and type of injury. Results High-speed going into the tackle, high impact force, collisions and contact with a player’s head/neck were identified as significant (p<0.01) risk factors for ball carriers (BCs) and tacklers. Midfield backs were significantly (p<0.01) more prone to injury when tackling than other players. Relatively few tacklers were penalised by referees for collision tackles (general play: 2.0%; injured players: 3.3%) and tackles above the line of the shoulder (general play: 5.9%; injured players: 16.7%). Conclusions Advice in national and international injury prevention programmes for reducing the risk of injury in tackles is strongly supported by the results obtained from this study. These programmes should be reviewed, however, to provide specific advice for each type of tackle. Stricter implementation of the Laws of Rugby relating to collisions and tackles above the line of the shoulder may reduce the number of head/neck injuries sustained by BCs.

The Epidemiology of Head Injuries in English Professional Rugby Union

Objectives:To undertake a detailed epidemiological study of head injuries sustained by professional rugby union players in order to define their incidence, nature, severity, and causes. Design:A 3-season prospective cohort design. Setting:13 English Premiership rugby union clubs. Participants:757 male rugby union players. Main Outcome Measures:Anatomical location, diagnosis, severity (number of days unavailable for training and match play), injury incident, and incidence of match and training injuries (injuries/1000 player-hours). Risk Factors:Playing position, use of headgear, and activity. Results:The overall incidence of match head injury was 6.6 injuries/1000 player-hours, and each injury resulted, on average, in 14 days lost-time. The overall incidence of match concussions was 4.1 injuries/1000 player-hours resulting, on average, in 13 days lost-time. Concussion was the third most common match injury for all players. A large proportion of the players (48%) were able to return to play safely within 7 days. Match concussions were most commonly associated with tackling head-on (28%), collisions (20%), and being tackled head-on (19%). The midfield backs were the playing position at the greatest risk of sustaining a concussion. Only 42% of players were removed from the field of play immediately after a concussion. Foul play was reported by the player to be associated with match head injury in 17% of cases. Mouthguard and headgear usage was associated with a reduced incidence of concussive injury. The overall incidence of training head injury was 0.05 injuries/1000 player-hours, and the overall incidence of training concussions was 0.02 injuries/1000 player-hours. Conclusions:The results showed that rugby union players were exposed to a high risk of noncatastrophic head injury and concussion, particularly whilst tackling and being tackled head-on. In all, 48% of players sustaining a concussion were able to return to play in less than 7 days. The clinical challenge when assessing the potentially concussed player during a game is compounded by the current regulations regarding the permanent replacement of injured players. Injury prevention strategies should be focussed on minimizing the risk and force of direct contact to the head in the tackle.

Consensus statement on epidemiological studies of medical conditions in tennis, April 2009

Background: The reported incidence, severity and nature of injuries sustained in tennis vary considerably between studies. While some of these variations can be explained by differences in sample populations and conditions, the main reasons are related to differences in definitions and methodologies employed in the studies. Objective: This statement aims to review existing consensus statements for injury surveillance in other sports in order to establish definitions, methods and reporting procedures that are applicable to the specific requirements of tennis. Design: The International Tennis Federation facilitated a meeting of 11 experts from seven countries representing a range of tennis stakeholders. Using a mixed methods consensus approach, key issues related to definitions, methodology and implementation were discussed and voted on by the group during a structured 1-day meeting. Following this meeting, two members of the group collaborated to produce a draft statement, based on the group discussions and voting outcomes. Three revisions were prepared and circulated for comment before the final consensus statement was produced. Results: A definition of medical conditions (injuries and illnesses) that should be recorded in tennis epidemiological studies and criteria for recording the severity and nature of these conditions are proposed. Suggestions are made for recording players’ baseline information together with recommendations on how medical conditions sustained during match play and training should be reported. Conclusions: The definitions and methodology proposed for recording injuries and illnesses sustained during tennis activities will lead to more consistent and comparable data being collected. The surveillance procedures presented here may also be applicable to other racket sports.

A framework for recording recurrences, reinjuries, and exacerbations in injury surveillance.

A previous injury can increase the risk of sustaining a similar injury by up to an order of magnitude. To understand the role of previous injury as a risk factor, it is necessary to consider, among other issues, the clinical status of the first (index) injury at the time of the subsequent (recurrent) injury: currently, the inconsistent use of descriptive terms for recurrent injuries makes this extremely difficult. Although recent consensus statements on injury definitions based on return-to-play criteria have provided a consistent methodology for recording and reporting index and recurrent injuries, these statements do not differentiate between the types of recurrent injuries that can occur. This paper presents a recording and reporting framework that subcategorizes recurrent injuries into reinjuries and exacerbations on the basis of whether a player was fully recovered from the preceding index injury, with the state of fully recovered determined by medical opinion. A reinjury is a repeat episode of a fully recovered index injury and an exacerbation is a worsening in the state of a nonrecovered index injury. With this more detailed framework, researchers will be able to investigate risk factors for reinjuries and exacerbations separately, and they will be able to investigate how well players have been rehabilitated before returning to full training and match play.