Why Median Severity and Ordinal Scale Severity Values should not be used for Injury Burden Results: A Critical Review.

Injury burden is a composite measure of injury incidence and mean severity; this parameter has been reported as an output measure from injury surveillance studies in rugby for over 20 years. The benefits of reporting injury burden results have, more recently, been recognised in other sports. This wider use of injury burden as an output measure from injury surveillance studies has, however, highlighted misunderstandings about how to calculate, present and interpret injury burden data. The aim of this critical review is to explain why median severity and ordinal severity scales should not be used to calculate and report injury burden results in injury surveillance studies. Equations are presented to show how injury burden results should be calculated, and graphs and tables are presented to explain the errors that are introduced when median severity and ordinal scales of severity are used instead of mean severity. This critical review is intended to highlight the correct procedures for calculating, reporting and interpreting injury burden results in order to avoid incorrect results, conclusions and injury prevention recommendations being published.

Risk Factors for Knee Osteoarthritis in Retired Professional Footballers: A Cross-Sectional Study.

OBJECTIVE: To determine risk factors for 3 knee osteoarthritis (KOA) outcomes, knee pain (KP), radiographic KOA (RKOA), and total knee replacement (TKR) in professional footballers. DESIGN: This was a cross-sectional study involving a postal questionnaire, followed by radiographic assessment in a subcohort of responders. SETTINGS AND PARTICIPANTS: Four thousand seven hundred seventy-five questionnaires were sent to retired professional footballers, who had played in the English football league, and 1207 responded. Of these, 470 underwent knee radiographs. ASSESSMENT OF RISK FACTORS: Potential factors include age, body mass index (BMI), knee alignment, a history of football-related knee injury, and training hours (during career) were collected through the questionnaire. MAIN OUTCOME MEASURES: Knee osteoarthritis outcomes were current KP (pain for most days of the previous month), TKR (self-reported), and RKOA (observed through radiographs). RESULTS: Football-related injury was the strongest risk factor for KP [adjusted odds ratio (aOR), 4.22; 95% confidence interval (CI), 3.26-5.48], RKOA [aOR, 2.88; 95% CI, 1.81-4.59], and TKR [aOR, 4.83; 95% CI, 2.87-8.13]. Footballers had a 7% increased risk of RKOA for every 1000 hours trained. Although age and gout were associated with all 3 KOA outcomes, BMI, nodal osteoarthritis (OA), a family history of OA, knee malalignment, and 2D:4D ratio were associated with one or another of these 3 KOA outcomes. CONCLUSION: This study is the first to examine KOA risk factors in retired professional footballers. The study has identified several risk factors, both specific (eg, knee injury and training dose) and nonspecific (eg, age and gout) to footballers. This may be used to develop prevention strategies to reduce the risk of KOA in professional footballers after retirement.

Eight-season epidemiological study of match injuries in women's international rugby sevens.

This study aimed to describe anthropometry and incidence, nature and causes of match injuries in women's international rugby sevens and to compare these with results reported previously for men's international rugby sevens. The study comprised an 8-season, prospective study of World Rugby's women's Sevens World Series. Over the eight seasons, the overall incidence of injury was 105.6 (95% CI: 96.0 to 116.3) injuries/1000 player-match-hours with a mean injury severity of 53.4 (95% CI: 46.9 to 59.9) days-absence. There were no statistically significant trends for backs or forwards in the incidence (backs: p = 0.470; forwards: p = 0.242) or mean severity (backs: p = 0.098; forwards: p = 0.544) of injuries sustained over the 8-season period. Head/face (20.8%), knee (19.7%), ankle (11.3%) and shoulder/clavicle (8.4%) were the most common injury locations while ligament sprain (31.7%), concussion (15.6%), haematoma/bruise (11.5%) and fracture (11.5%) were the most common types of injury sustained. Being-tackled (35.4%), tackling (26.3%), collisions (13.8%) and rucks (8.8%) were the match events responsible for most injuries. The study indicates that injury burden in women's international rugby sevens (5,640 days-absence/1000 player-match-hours; 95% CI: 5,123 to 6,209) is similar to that reported previously for men's international rugby sevens (5,263 days-absence/1000 player-match-hours; 95% CI: 5,000 to 5,540).

The epidemiology of kicking injuries in professional Rugby Union: A 15-season prospective study.

PURPOSE: While kicking in Rugby Union can be influential to match outcome, the epidemiology of kicking injuries remains unknown. This study therefore aimed to investigate the epidemiology of injuries attributed to kicking in professional rugby, including playing position-specific effects and differences in kicking volumes and kick types. METHODS: Fifteen seasons of injury surveillance data and two seasons of match kicking characteristics from professional rugby players were analyzed. Incidence, propensity, and severity of kicking-related injuries were calculated together with the locations and types of these injuries. Position-related differences in match kicking types and volumes were also established. RESULTS: Seventy-seven match and 55 training acute-onset kicking injuries were identified. The match kicking injury incidence for backs was 1.4/1000 player-match-hours. Across all playing positions, the propensity for match kicking injury was 0.57 injuries/1000 kicks. Fly-halves sustained the greatest proportion of match kicking injuries (47%) and performed the greatest proportion of match kicks (46%); an average propensity for match kicking injury (0.58/1000 kicks). Scrum-halves executed 27% of match-related kicks but had a very low propensity for match kicking injury (0.17/1000 kicks). All other positional groups executed a small proportion of match-related kicks but a high propensity for match kicking injury. Ninety-two percent of match kicking injuries occurred in the pelvis or lower limb, with the majority sustained by the kicking limb. 21% of all match kicking injuries were associated with the rectus femoris muscle. CONCLUSION: Match kicking profiles and kicking injuries sustained are position-dependent, which provides valuable insight for developing player-specific conditioning and rehabilitation protocols.

Ten-season epidemiological study of match injuries in men's international rugby sevens.

The aim of this study was to describe the incidence, nature and causes of match injuries in men's international rugby sevens and to compare these to values for international rugby fifteens. The study comprised a 10-season, whole population, prospective study of the Sevens World Series. Over the ten seasons, the overall incidence of injury was 122.4 (95% CI = 116.3 to 128.9) injuries/1000 player-match-hours and the mean severity of injury was 43.0 (95% CI = 40.3 to 45.7) days-absence. There was an increasing trend in the incidence of injury over the ten-season period (slope = 5.3 injuries/1000 player-hours/season, R2 = 0.68, p = 0.003) but no trend in the mean severity of injury (slope = 0.02 days/season, R2 < 0.01, p = 0.971). Head/face (15.7%), knee (15.6%), ankle (15.4%) and shoulder/clavicle (11.9%) were the most common injury locations and ligament sprain (30.5%), muscle strain (16.4%), concussion (12.6%) and haematoma/bruise (10.6%) the most common types of injury sustained. Being-tackled (33.1%), tackling (23.4%), running (16.1%) and collisions (12.4%) were the most common events leading to injury. These results indicate that the burden of injury in international rugby sevens is two to three times higher than that reported for international rugby fifteens.

Patterns of training volume and injury risk in elite rugby union: An analysis of 1.5 million hours of training exposure over eleven seasons.

Rugby union is a popular team sport that demands high levels of physical fitness and skill. The study aim was to examine trends in training volume and its impact on injury incidence, severity and burden over an 11-season period in English professional rugby. Data were recorded from 2007/08 through 2017/18, capturing 1,501,606 h of training exposure and 3,782 training injuries. Players completed, on average, 6 h 48 minutes of weekly training (95% CI: 6 h 30 mins to 7 h 6 mins): this value remained stable over the 11 seasons. The mean incidence of training-related injuries was 2.6/1000 player-hours (95% CI: 2.4 to 2.8) with a mean severity rising from 17 days in 2007/08 to 37 days in 2017/18 (Change/season = 1.773, P <0.01). Rate of change in severity was dependent on training type, with conditioning (non-gym-based) responsible for the greatest increase (2.4 days/injury/season). As a result of increasing severity, injury burden rose from 51 days absence/1000 player-hours in 2007/08 to 106 days' absence/1000 player-hours in 2017/18. Despite the low incidence of injury in training compared to match-play, training accounted for 34% of all injuries. Future assessments of training intensity may lead to a greater understanding of the rise in injury severity.

"Recognize and Remove": A Universal Principle for the Management of Sports Injuries.

OBJECTIVE: To identify the locations and types of injury that result in players not being immediately removed from the field of play when injured and to quantify the magnitude of the situation. DESIGN: Prospective cohort epidemiological study with definitions and procedures compliant with the international consensus statement for studies in rugby. SETTING: Sevens World Series (SWS) (2008-2016) and Rugby World Cup (RWC) (2007, 2011, 2015). PARTICIPANTS: Players from 17 countries taking part in the SWS and 22 countries taking part in the RWC. MAIN OUTCOME MEASURES: Location, type, and mean severity of injury, period of match when the injury occurred and whether players were removed from the field of play when injured. RESULTS: Injured players (51.5%) in the SWS and 33.1% of injured players in the RWC were immediately removed from the field of play at the time of injury. The percentages of players immediately removed varied from 16.7% for hand fractures (severity: 71 days) to 96.7% for shoulder dislocations/subluxations (severity: 105 days) during the SWS and from 4.5% for shoulder ligament sprains (severity: 25 days) to 65.9% for concussions (severity: 9 days) during the RWC. The percentage of players immediately removed from play when injured was not related to the severity of the injury sustained. CONCLUSIONS: A high proportion of players continue to play (in the same game) after sustaining an injury although the likelihood of being removed from play is not dependent on injury severity.

Eight-season epidemiological study of injuries in men's international Under-20 rugby tournaments.

The aim of this study was to define the incidence and nature of match injuries sustained in men's international under-20 rugby. The study comprised an 8-season prospective study of 16 international under-20 rugby tournaments. Procedures complied with the consensus statement for epidemiological studies in rugby. Outputs included players' mean age, stature and body mass and incidence, severity, location, type and cause of match injuries. The overall incidence of injury was 49.7 injuries/1000 player-match-hours (backs: 48.3; forwards: 50.9) with a mean severity of 32.2 days-absence (backs: 29.4; forwards: 34.4). There were no significant changes in incidence or severity of injury over the study period. Shoulder/clavicle (18.3%), head/face (16.4%), knee (13.7%) and ankle (13.7%) were the most common injury locations and ligament sprain (35.4%), haematoma/bruise (15.9%), concussion (12.5%) and muscle strain (11.2%) the most common types of injury. Being-tackled (29.2%), tackling (24.0%) and collisions (14.3%) were the most common events leading to injury. The results confirm that international under-20 rugby has a high incidence and severity of injury but the incidence is half that reported for senior international players. There was no significant change in the overall incidence of injury at the Under-20 level in the period 2008 to 2016.

2016 Rio Olympics: an epidemiological study of the men's and women's Rugby-7s tournaments.

OBJECTIVE: To determine the incidence, severity and nature of injuries sustained during the men's and women's 2014/2015 and 2015/2016 Sevens World Series (SWS) and 2016 Olympic Games Rugby Sevens tournaments. DESIGN: A prospective cohort study. PARTICIPANTS: All players from the core teams competing in the men's and women's 2014/2015 and 2015/2016 SWS (men: 15 teams; women: 11 teams) and all players from the men's (12 teams) and women's (12 teams) 2016 Rio Olympics tournaments. RESULTS: The gold, silver and bronze medal-winning women's teams contained bigger players (body mass and stature) than other teams but the men's medal winning teams came from across the size spectrum of men's teams competing at Rio 2016. The incidences of injury in the men's tournaments (2014/2015 SWS: 107.7 injuries/1000 player-match-hours (95% CI 90.9 to 127.4); 2015/2016 SWS: 109.7 (95% CI 93.7 to 128.6); Rio 2016: 124.5 (95% CI 73.7 to 210.2)) were higher but not statistically significant than those in the equivalent women's tournaments (2014/2015 SWS: 88.5 (95% CI 68.4 to 114.5), p=0.250; 2015/2016 SWS: 109.4 (95% CI 84.2 to 142.2), p=0.984; Rio 2016: 71.1 (95% CI 35.6 to 142.2), p=0.208). There were no statistically significant differences between the incidences of injury at the men's and women's 2016 Rio Olympics and the equivalent 2014/2015 (men: p=0.603; women: p=0.562) and 2015/2016 (men: p=0.652; women: p=0.254) SWS. CONCLUSIONS: The incidence, severity and nature of the injuries sustained during the men's and women's Rio 2016 Rugby-7s tournaments fell within the normal range of values for international Rugby-7s tournaments.

Rugby World Cup 2015: World Rugby injury surveillance study.

OBJECTIVE: To determine the incidence, severity and nature of injuries sustained during the Rugby World Cup (RWC) 2015 together with the inciting events leading to the injuries. DESIGN: A prospective, whole population study. POPULATION: 639 international rugby players representing 20 countries. METHOD: The study protocol followed the definitions and procedures recommended in the consensus statement for epidemiological studies in rugby union; output measures included players' age (years), stature (cm), body mass (kg) and playing position, and the group-level incidence (injuries/1000 player-hours), mean and median severity (days-absence), location (%), type (%) and inciting event (%) for match and training injuries. RESULTS: Incidence of injury was 90.1 match injuries/1000 player-match-hours (backs: 100.4; forwards: 81.1) and 1.0 training injuries/1000 player-training-hours (backs: 0.9; forwards: 1.2). The mean severity of injuries was 29.8 days-absence (backs: 30.4; forwards: 29.1) during matches and 14.4 days-absence (backs: 6.3; forwards: 19.8) during training. During matches, head/face (22.0%), knee (16.2%), muscle-strain (23.1%) and ligament-sprain (23.1%) and, during training, lower limb (80.0%) and muscle-strain (60.0%) injuries were the most common locations and types of injury. Being-tackled (24.7%) was the most common inciting event for injury during matches and rugby-skills-contact activities (70.0%) the most common during training. CONCLUSIONS: While the incidence, nature and inciting events associated with match injuries at RWC 2015 were similar to those reported previously for RWCs 2007 and 2011, there were increasing trends in the mean severity and total days-absence through injury.

Evaluation of World Rugby's concussion management process: results from Rugby World Cup 2015.

OBJECTIVE: To evaluate World Rugby's concussion management process during Rugby World Cup (RWC) 2015. DESIGN: A prospective, whole population study. POPULATION: 639 international rugby players representing 20 countries. METHOD: The concussion management process consisted of 3 time-based, multifaceted stages: an initial on-pitch and/or pitch-side assessment of the injury, a follow-up assessment within 3 hours and an assessment at 36-48 hours. The initial on-pitch assessment targeted obvious signs of concussion, which, if identified, lead to a 'permanent removal from play' decision and a diagnosis of concussion. If the on-pitch diagnosis was unclear, a 10-min off-pitch assessment was undertaken for signs and symptoms of concussion leading to a 'suspected concussion with permanent removal from play' or a 'no indication of concussion with return to play' decision. Evaluations at 3 and 36-48 hours postmatch lead to diagnoses of 'confirmed concussion' or 'no concussion'. Medical staff's decision-making was supported during each stage by real-time video review of events. Players diagnosed with confirmed concussion followed a 5-stage graduated-return-to-play protocol before being allowed to return to training and/or competition. RESULTS: Players were evaluated for concussion on 49 occasions, of which 24 resulted in diagnoses of concussion. Fourteen players showing on-pitch signs of concussion were permanently removed from play: 4 of the 5 players removed from play following off-pitch medical room evaluation were later diagnosed with a confirmed concussion. Five players not exhibiting in-match signs or symptoms of concussion were later diagnosed with concussion. The overall incidence of concussion during RWC 2015 was 12.5 concussions/1000 player-match-hours. CONCLUSIONS: This study supports the implementation of a multimodal, multitime-based concussion evaluation process to ensure that immediate and late developing concussions are captured.

'FIFA 11 for Health' for Europe. 1: effect on health knowledge and well-being of 10- to 12-year-old Danish school children.

AIM: To modify the 'FIFA 11 for Health' programme to the European situation, and to assess its effects on health knowledge and well-being in Danish school children. METHOD: A two-cohort study with seven intervention and two control schools. Of the 546 Danish children (boys 269; girls 277) of mean age 11.1 (±0.4) years from five city and four country-side schools, 402 undertook the 'FIFA 11 for Health' programme and 144 acted as controls. As part of each school's PE curriculum, seven intervention schools received a 45 min Play Football period (football skills and 3 vs 3 games) and a 45 min Play Fair period (health issues and football drills) on a weekly-basis for 11 weeks. Control participants continued with their regular school PE activities. Participants completed preintervention and postintervention health knowledge and well-being questionnaires. RESULTS: Overall, health knowledge increase was significantly (p<0.05) greater for the intervention group (11.9%) than the control group (2.6%). Significant (p<0.05) between-group differences were obtained for 8 of 10 health topics (6.1-20.2%) related to physical activity, nutrition, hygiene and well-being. The social dimension of the well-being questionnaire was significantly (p<0.05) improved in the intervention group compared to the control group, but there were no significant between-group effects for the physical, emotional and school dimensions. Positive reporting about the programme was given by 72.4% of the children and only 4.8% reported negatively. CONCLUSIONS: The 'FIFA 11 for Health' programme modified for Europe demonstrated positive effects on children's health knowledge and social dimension of well-being, thereby providing evidence that the football-based health education programme can be used effectively within a European school's curriculum to increase physical activity, well-being and health knowledge.

Managing player load in professional rugby union: a review of current knowledge and practices.

BACKGROUND: The loads to which professional rugby players are subjected has been identified as a concern by coaches, players and administrators. In November 2014, World Rugby commissioned an expert group to identify the physical demands and non-physical load issues associated with participation in professional rugby. OBJECTIVE: To describe the current state of knowledge about the loads encountered by professional rugby players and the implications for their physical and mental health. FINDINGS: The group defined 'load' as it relates to professional rugby players as the total stressors and demands applied to the players. In the 2013-2014 seasons, 40% of professional players appeared in 20 matches or more, and 5% of players appeared in 30 matches or more. Matches account for ∼5-11% of exposure to rugby-related activities (matches, team and individual training sessions) during professional competitions. The match injury rate is about 27 times higher than that in training. The working group surmised that players entering a new level of play, players with unresolved previous injuries, players who are relatively older and players who are subjected to rapid increases in load are probably at increased risk of injury. A mix of 'objective' and 'subjective' measures in conjunction with effective communication among team staff and between staff and players was held to be the best approach to monitoring and managing player loads. While comprehensive monitoring holds promise for individually addressing player loads, it brings with it ethical and legal responsibilities that rugby organisations need to address to ensure that players' personal information is adequately protected. CONCLUSIONS: Administrators, broadcasters, team owners, team staff and the players themselves have important roles in balancing the desire to have the 'best players' on the field with the ongoing health of players. In contrast, the coaching, fitness and medical staff exert significant control over the activities, duration and intensity of training sessions. If load is a major risk factor for injury, then managing training loads should be an important element in enabling players to perform in a fit state as often as possible.

Subsequent Injuries and Early Recurrent Diagnoses in elite Rugby Union Players.

An eight-season (2005/06-2012/13) prospective cohort design was used to record time-loss injuries in 15 English Premiership teams. Data pertaining to a total of 1 556 players and 9 597 injuries (8 180 subsequent) were included in the analysis. Injuries subsequent to an index injury were classified as (1) New: different site; (2) Local: same site (and different type); or (3) Recurrent: same site and type. The severity of subsequent injuries (days missed) was compared with their related index injury. The proportions of early (<2 months), late (2-12 months) and delayed (>12 months) subsequent injuries were compared across injury classifications and diagnosis groupings. The majority of subsequent injuries (70%) were classified as new injuries, with 14% local and 16% recurrent. A large proportion of recurrent subsequent injuries (42%) occurred within two months of return-to-play. Subsequent injuries were not more severe than their corresponding index injury (effect sizes <0.20). Specific local and recurrent subsequent injury diagnoses with the highest risk of occurring within two months of return-to-play were: 'neck muscle strain', 'ankle joint capsule sprain', and 'cervical nerve root' injuries. These findings may be used to drive targeted secondary prevention efforts, such as reconsideration of return-to-play protocols for neck muscle strain injuries.

Should player fatigue be the focus of injury prevention strategies for international rugby sevens tournaments?

OBJECTIVE: To assess the incidence, severity and nature of injuries, to determine risk factors for injury and to identify potential injury prevention strategies in men's international Rugby-7s tournaments. DESIGN: A prospective cohort study. PARTICIPANTS: Players from core teams competing in matches at 6 Sevens World Series from 2008/2009 to 2014/2015. RESULTS: The incidence of injury across all Series was 108.3 injuries/1000 player-match-hours (backs: 121.0; forwards: 91.5) with a mean severity of 44.2 days (backs: 46.1; forwards: 40.9) and a median severity of 28 days (backs: 29; forwards: 26). The proportion of injuries sustained in the second half was significantly higher (60%; p<0.001) than the first half of matches and the proportion increased from match to match and day to day in a tournament. The knee (17.4%), ankle (15.9%) and posterior thigh (13.2%) were the most common injury locations for backs and the knee (18.5%), head/face (17.3%) and shoulder/clavicle (13.0%) for forwards. The four most common injuries across all players were knee ligament (13.0%), ankle ligament (12.8%), concussion (10.4%) and posterior thigh muscle strains (9.8%). CONCLUSIONS: The incidence of injury in Rugby-7s suggests that teams require squads of around 20 players for a Sevens World Series. The higher incidence of injury in the second half of matches is probably the result of player fatigue; therefore, injury prevention strategies for teams and the Governing Body should address this issue. The results presented support the World Rugby trial allowing 'rolling substitutes' during Sevens World Series matches, as this approach may help to mitigate the effects of player fatigue during the second half of matches.

'FIFA 11 for Health' for Europe. II: effect on health markers and physical fitness in Danish schoolchildren aged 10-12†years.

OBJECTIVES: To evaluate whether a modified 'FIFA 11 for Health' programme for non-communicable diseases had effects on body composition, blood pressure and physical fitness of Danish schoolchildren aged 10-12 years. DESIGN: A cluster-randomised controlled study with 7 intervention and 2 control schools. PARTICIPANTS: 546 Danish 5th grade municipal schoolchildren allocated to an intervention group (IG; n=402: 11.1±0.4 (±SD) years, 150.1±7.0 cm, 41.3±8.4 kg) and a control group (CG; n=144: 11.0±0.5 years, 151.2±7.8 cm, 41.3±9.0 kg). INTERVENTION: As part of the physical education (PE) curriculum, IG carried out 2 weekly 45 min 'FIFA 11 for Health' sessions focusing on health issues, football skills and 3v3 games. CG continued regular school PE activities. Measurements of body composition, blood pressure at rest, Yo-Yo intermittent recovery level 1 children's test (YYIR1C), balance, jump and sprint performance were performed before and after the 11-week study period. RESULTS: During the 11-week study period, systolic blood pressure (-3.5 vs 0.9 mm Hg), mean arterial blood pressure (-1.9 vs 0.4 mm Hg), body mass index (-0.02 vs 0.13 kg/m2) and body fat percentage (-0.83% vs -0.04%) decreased more (p<0.05) in IG than in CG. Within-group improvements (p<0.05) were observed in IG for 20 m sprint (4.09±0.29 to 4.06±0.28 s) and YYIR1C performance (852±464 to 896±517 m), but these changes were not significantly different from CG, and balance or jump performance remained unchanged in both groups. CONCLUSIONS: The modified 'FIFA 11 for Health' programme has beneficial effects on body composition and blood pressure for Danish schoolchildren aged 10-12 years, thereby providing evidence that this football-based health education programme can directly impact participants' cardiovascular health profile.

Time loss injuries compromise team success in Elite Rugby Union: a 7-year prospective study.

BACKGROUND: A negative association between injuries and team success has been demonstrated in professional football, but the nature of this association in elite Rugby Union teams is currently unclear. AIM: To assess the association between injury burden measures and team success outcomes within professional Rugby Union teams. METHODS: A seven-season prospective cohort design was used to record all time-loss injuries incurred by English Premiership players. Associations between team success measures (league points tally and Eurorugby Club Ranking (ECR)) and injury measures (injury burden and injury days per team-match) were modelled, both within (changes from season to season) and between (differences averaged over all seasons) teams. Thresholds for the smallest worthwhile change in league points tally and ECR were 3 points and 2.6%, respectively. RESULTS: Data from a total of 1462 players within 15 Premiership teams were included in the analysis. We found clear negative associations between injury measures and team success (70-100% likelihood), with the exception of between-team differences for injury days per team-match and ECR, which was unclear. A reduction in injury burden of 42 days (90% CI 30 to 70) per 1000 player hours (22% of mean injury burden) was associated with the smallest worthwhile change in league points tally. CONCLUSIONS: Clear negative associations were found between injury measures and team success, and moderate reductions in injury burden may have worthwhile effects on competition outcomes for professional Rugby Union teams. These findings may be useful when communicating the value of injury prevention initiatives within this elite sport setting.

Defining a safe player run-off zone around rugby union playing areas.

OBJECTIVES: To identify the circumstances in which international rugby players exit the playing area during match activities and to define a safe run-off distance around the playing area. METHOD: An observational study using video recordings of 102 matches associated with the Rugby World Cup (2011), Rugby Championship (2013, 2014) and Six Nations Championship (2013, 2014) were used to analyse every event in which one or more players exited the playing area during normal match activities. The circumstances in which a player exited the playing area were categorised using a range of parameters: playing position, location, out-of-play region, match activity, distance travelled over the touchline, contacts made with pitchside fixtures and fittings. RESULTS: Ninety-five per cent of player-excursions took place within 5.2 m of the touchline. Players exiting the playing area were nearly three times more likely to be a back than a forward (p<0.001) and the event was more likely to take place when a team was defending than attacking (p<0.001). Being forced out of play during a contact event (70%) was the major reason for players exiting the playing area. Most players (88%) exiting the playing area only made contact with the perimeter area surface; a small proportion of players contacted touchline flags (6.1%), advertising boards (2.3%) and TV cameras/equipment (1.0%). CONCLUSIONS: A minimum hazard-free distance of 5 m around a Rugby pitch is proposed based on the 95% percentile frequency distribution of player-excursion events into the areas contiguous with the playing area.

Does long-distance air travel associated with the Sevens World Series increase players' risk of injury?

OBJECTIVE: To assess whether players who cross ≥6 time zones and/or undertake ≥10 h air travel prior to competition experience a higher risk of injury during the Sevens World Series than players not required to undertake this level of travel. DESIGN: Five-year, prospective, cohort study. PARTICIPANTS: All players from nine core teams competing in the Sevens World Series from 2008/2009 to 2013/2014. RESULTS: A total of 436 match injuries and 3363 player-match-hours of exposure were recorded in the study, which corresponds to an overall incidence of 129.6 injuries/1000 player-match-hours, irrespective of the nature of pretournament travel. The incidence of injury for those players crossing ≥6 time zones and undertaking ≥10 h air travel prior to competition (99.3 injuries/1000 player-match-hours) was significantly lower than that of players undertaking ≥10 h air travel but crossing ≤2 time zones prior to competition (148.8 injuries/1000 player-match-hours; p=0.003) and of those undertaking ≤3 h air travel and crossing ≤2 time zones prior to competition (146.4 injuries/1000 player-match-hours; p=0.004). There was no significant difference in the incidence of injury for players crossing ≤2 time zones in the week prior to competition, irrespective of whether the length of air travel was ≤3 h or ≥10 h (p=0.904). Precompetition air travel had no significant effect (p=0.879) on the performance of teams in terms of their final Tournament ranking positions. CONCLUSIONS: There was no evidence to suggest that players were exposed to a greater risk of injury following extensive air travel and crossing multiple time zones prior to Tournaments in the Sevens World Series.

Epidemiology of concussion in men's elite Rugby-7s (Sevens World Series) and Rugby-15s (Rugby World Cup, Junior World Championship and Rugby Trophy, Pacific Nations Cup and English Premiership).

OBJECTIVE: To determine the incidence, nature and causes of concussions sustained during men's elite professional Rugby-7s and Rugby-15s. DESIGN: A prospective cohort study recording injuries classified as a time-loss concussion. POPULATION: Players competing in the following tournaments: Rugby 15s-English Premiership (2007/2008 to 2010/2011), Rugby World Cup (2007, 2011), Pacific Nations Cup (2012, 2013), Junior World Championship (2008, 2010-2013), Junior World Rugby Trophy (2008, 2010-2013); Rugby 7s-Sevens World Series (2008/2009, 2010/2011 to 2012/2013). METHOD: The study was implemented according to the international consensus statement for epidemiological studies in rugby union; the main outcome measures included the number, incidence (number of concussions/1000 player-match-hours), mean and median severity (days absence) and cause of concussion. RESULTS: The incidence of concussion in Rugby-7s was significantly higher than that in Rugby-15s (risk ratio=1.84; p<0.001). The severity of concussions were significantly higher in Rugby-7s than Rugby-15s (mean-Rugby-7s: 19.2, Rugby-15s: 10.1; median-Rugby 7s: 20, Rugby-15s: 7; p<0.001). The main causes of concussion were tackling (44.1%) in Rugby-7s and collisions (43.6%) in Rugby-15s. Significantly more (risk ratio=1.49; p=0.004) concussed players were removed immediately from the game in Rugby-7s (69.7%) compared to Rugby-15s (46.7%). CONCLUSIONS: Six actions were identified to improve the management of concussion in rugby: implement a pitch-side concussion assessment protocol; improve compliance with return-to-play protocols; work with referees to review the nature and consequences of collisions; improve players' tackle technique; investigate the forces involved in tackles and collisions; and evaluate reasons for the higher incidence of concussions in Rugby-7s.