Methods for epidemiological study of injuries to professional football players: developing the UEFA model

The perceptions of professional soccer players on the risk of injury from competition and training on natural grass and 3rd generation artificial turf

BACKGROUND

The purpose of this study was to describe professional soccer players' perceptions towards injuries, physical recovery and the effect of surface related factors on injury resulting from soccer participation on 3rd generation artificial turf (FT) compared to natural grass (NG).

METHODS

Information was collected through a questionnaire that was completed by 99 professional soccer players from 6 teams competing in Major League Soccer (MLS) during the 2011 season.

RESULTS

The majority (93% and 95%) of the players reported that playing surface type and quality influenced the risk of sustaining an injury. Players believed that playing and training on FT increased the risk of sustaining a non-contact injury as opposed to a contact injury. The players identified three surface related risk factors on FT, which they related to injuries and greater recovery times: 1) Greater surface stiffness 2) Greater surface friction 3) Larger metabolic cost to playing on artificial grounds. Overall, 94% of the players chose FT as the surface most likely to increase the risk of sustaining an injury.

CONCLUSIONS

Players believe that the risk of injury differs according to surface type, and that FT is associated with an increased risk of non-contact injury. Future studies should be designed prospectively to systematically track the perceptions of groups of professional players training and competing on FT and NG.

Epidemiology of injuries in elite taekwondo athletes: two Olympic periods cross-sectional retrospective study

OBJECTIVE

Taekwondo injuries differ according to the characteristics of the athletes and the competition. This analytical cross-sectional retrospective cohort study aimed to describe reported taekwondo injuries and to determine the prevalence, characteristics and possible risk factors for injuries sustained by athletes of the Spanish national team. In addition, we compared each identified risk factor-age, weight category, annual quarter, injury timing and competition difficulty level-with its relation to injury location and type.

SETTINGS

Injury occurrences in taekwondo athletes of the Spanish national team during two Olympic periods at the High Performance Centre in Barcelona were analysed.

PARTICIPANTS

48 taekwondo athletes (22 male, 26 female; age range 15-31 years) were studied; 1678 injury episodes occurred. Inclusion criteria were: (1) having trained with the national taekwondo group for a minimum of one sports season; (2) being a member of the Spanish national team.

RESULTS

Independently of sex or Olympic period, the anatomical sites with most injury episodes were knee (21.3%), foot (17.0%), ankle (12.2%), thigh (11.4%) and lower leg (8.8%). Contusions (29.3%) and cartilage (17.6%) and joint (15.7%) injuries were the prevalent types of injury. Chronological age, weight category and annual quarter can be considered risk factors for sustaining injuries in male and female elite taekwondists according to their location and type (p≤0.001).

CONCLUSIONS

This study provides epidemiological information that will help to inform future injury surveillance studies and the development of prevention strategies and recommendations to reduce the number of injuries in taekwondo competition.

Injury incidence in a sports school during a 3-year follow-up

PURPOSE

This study prospectively analysed sports injury incidence over 3 seasons in a regional sports school within an injury surveillance project, involving 372 athletes (12-19 years) from 16 different disciplines.

METHODS

A personal sports diary was used to record all sporting activities daily for every athlete. Injuries (time-loss definition) were registered via a standardized questionnaire.

RESULTS

Sports injury incidence (injuries/1,000 h) evolved from 3.9 in the first year to 4.8 in the second (p < 0.01) and down to 2.8 in the third (p < 0.001, compared to the preceding periods). Significant decreases of injury incidence in the third year were also observed when classifying injuries as traumatic or overuse, and as new or recurrent. The proportion of recurrent injuries was lower in the third period (11 %) when compared to the first (19.5 %, p < 0.05) and the second one (26.3 %, p < 0.05). Injury incidence was lowest during the third period for all severity categories. The same was found when considering injuries within racket, team and individual sports.

CONCLUSIONS

Implementing an injury surveillance system in this setting was associated with a lower injury incidence in the third observation period. This project may have influenced stakeholders' awareness and attitude towards the sports injury problematic.

Reducing muscle injuries and reinjuries in one italian professional male soccer team

BACKGROUND

The incidence rate of muscle injuries and re-injuries in professional elite soccer players actually is very high and may interfere with the fate of a championship.

PURPOSE

To investigate the effect of a two-tiered injury prevention programme on first injury and re-injury incidence in top level male soccer players. Study design.

CASE SERIES STUDY

Muscle injuries and re-injuries sustained by a group of 36 soccer player of an italian elite soccer team have been collected during 2010-2011 season. These data have been compared with those collected during the previous season in the same elite soccer team.

RESULTS

A total of 64 injuries occurred, 36 (56%) of which during practice and 28 (44%) during matches. Muscle injuries accounted for 31.3% of the total (n=20), 70% (n=14) of which occurred during practice and 30% (n=6) during matches. Hamstring were the muscles most often injured (n=11) In all, 3 re-injuries occurred (15% of muscle injuries). No early re-injuries occurred. The incidence was 2.5 injuries/1000 hours and the burden was 37 days absence/1000 hours.

CONCLUSIONS

Through the implementation of a group and personalized injury prevention program, we were able to reduce the total number of muscle injuries and days absent because of injury, in a team of elite soccer players, as compared to the previous season. Specifically, muscle injuries accounted for 31% of all injuries, as compared to 59% of all injuries sustained by the team during the previous season. The number of injuries/1000 hours of exposure was reduced by half (from 5.6 to 2.5) and the days absent/1000 hours fell from 106 to 37.

Superior compliance with a neuromuscular training programme is associated with fewer ACL injuries and fewer acute knee injuries in female adolescent football players: secondary analysis of an RCT

BACKGROUND

Little is known about the influence of compliance with neuromuscular training (NMT) on the knee injury rate in football.

AIM

To evaluate team and player compliance with an NMT programme in adolescent female football and to study the association between compliance and acute knee injury rates.

METHODS

Prospective cohort study based on a cluster randomised controlled trial on players aged 12-17 years with 184 intervention teams (2471 players) and 157 control teams (2085 players). Exposure and acute time loss knee injuries were recorded. Team and player compliance was recorded by the coaches on a player attendance form. The intervention group was divided into tertiles of compliance. Injury rates were compared by calculating rate ratios (RRs) and 95% CIs using exact Poisson tests with the low-compliance tertile as reference. Seasonal compliance trends were analysed using linear regression.

RESULTS

Players in the high-compliance tertile had an 88% reduction in the anterior cruciate ligament (ACL) injury rate (RR 0.12, 95% CI 0.01 to 0.85), whereas the rate in the control group players was not significantly different from those in the low-compliance tertile (RR 0.77, 95% CI 0.27 to 2.21). A significant deterioration occurred in team (b=-3.0% per month, 95% CI -5.2 to -0.8) and player (b=-5.0% per month, 95% CI -7.1 to -2.9) compliance over the season.

CONCLUSIONS

Players with high compliance with the NMT programme had significantly reduced ACL injury rate compared with players with low compliance. Significant deterioration in team and player compliance occurred over the season.

Single nucleotide polymorphisms associated with non-contact soft tissue injuries in elite professional soccer players: influence on degree of injury and recovery time

BACKGROUND

The biological mechanisms involved in non-contact musculoskeletal soft tissue injuries (NCMSTI) are poorly understood. Genetic risk factors may be associated with susceptibility to injuries, and may exert marked influence on recovery times.

METHODS

Data on type and degree of injury and recovery time were collected in 73 male professional soccer players (43 White, 11 Black Africans and 19 Hispanics) who suffered total of 242 injuries (203 muscle, 24 ligament, and 15 tendon injuries). One single nucleotide polymorphism (SNPs) in the following genes were analyzed: Elastin (ELN); Titin (TTN); SRY-related HMG-box (SOX15); Insulin-like growth factor 2 (IGF2); Chemokine, CC motif, ligand 2 (CCL2); Collagen type 1 alpha 1(COL1A1); Collagen type 5 alpha 1 (COL5A1), and Tenascin C (TNC).

RESULTS

There was evidence of a statistically significant association between the degree of injury and the IGF2 genotype (P = 0.034). In addition, there was evidence of a statistically significant association between the degree of muscle injury and CCL2 (P = 0.026) Finally, there was evidence of a statistically significant association between ELN and degree of injury (p = 0.009) and recovery time (P = 0.043). There was no evidence of a statistically significant association between any of the genes studied and degree of injury or recovery time for tendon injuries.

CONCLUSION

SNPs in the IGF2, CCL2, and ELN genes may be associated to the degree and recovery time of NCMSTI.

Head and neck injuries in professional soccer

OBJECTIVE

To investigate the rate of and risk factors for head and neck injury in male soccer.

DESIGN

Prospective cohort study.

SETTING

Professional soccer.

PARTICIPANTS

Twenty-six European teams between 2001/2002 and 2009/2010.

ASSESSMENT OF RISK FACTORS

Simple and multiple risk factor analyses were evaluated using Cox regression for player-related variables and logistic regression for match-related variables.

MAIN OUTCOME MEASURES

Injury rate (number of time loss injuries per 1000 hours).

RESULTS

A total of 136 head and neck injuries were recorded (2.2% of all injuries). The head and neck injury rate was 0.17 (0.06 concussions) per 1000 hours. There was a 20-fold higher rate of head and neck injury during match play compared with training (rate ratio [RR], 20.2; 95% confidence interval [CI], 13.3-30.6) and a 78-fold higher rate of concussions (RR, 78.5; 95% CI, 24.4-252.5). Mean layoff for concussion was 10.5 days, but 27% of the concussed players returned to play within 5 days. Defender was the only significant player-related risk factor for head and neck injuries in the multiple analysis (RR, 1.8; 95% CI, 1.0-3.1), whereas no significant variables were identified for concussions.

CONCLUSIONS

Head and neck injuries were relatively uncommon in professional soccer. Defender was the playing position most at risk. More than one-quarter of the concussed players returned to play before what is recommended in the consensus statements by the major sports governing bodies.

Does Ramadan affect the risk of injury in professional football?

OBJECTIVE

To investigate whether fasting during Ramadan influences injury incidence in professional Muslim and non-Muslim footballers.

DESIGN

Prospective cohort study.

SETTING

Professional First Division League of Qatar.

PARTICIPANTS

About 527 male football players (462 Muslim and 65 non-Muslim) from 7 league clubs (first year of data collection) and 8 clubs (second and third years).

INTERVENTIONS

Daily collection of training and match exposure from August 2008 until April 2011 by club medical staff. Injuries during training and match play were recorded on standardized injury cards.

MAIN OUTCOME MEASURES

Injury incidence was calculated as number of injuries per hour exposed to risk, and expressed as rate per 1000 hours. The probability of injury for different Arabic months between Muslims and non-Muslims was calculated using Generalized Estimating Equations (GEEs).

RESULTS

There was no significant difference in total, match, and training injury incidence between the Ramadan and non-Ramadan periods. Non-Muslim footballers had a significantly higher injury incidence rate than Muslim footballers both during Ramadan (8.5 vs 4.0 injuries/1000 hours, P = 0.009) and non Ramadan (6.6 vs 4.9 injuries/1000 hours, P = 0.004) periods. The GEE analysis revealed that after adjusting for age and random factors (month and club), the probability of match injury among non-Muslims was the highest in Ramadan and the 2 consecutive following months (adjusted odds ratio of injury among non-Muslims compared with Muslims was 3.7 [95% confidence interval (CI), 1.7-7.9], P = 0.001 during Ramadan (ninth) month; 2.4 (95% CI, 1.1-4.9), P = 0.021 during 10th month; and 2.7 (95% CI, 1.2-5.8), P = 0.013 during 11th month). Finally, there was no change in injury patterns over the months of the Islamic calendar.

CONCLUSIONS

Ramadan does not impact injury incidence for Muslim footballers in Qatar, suggesting the current adjustments and scheduling of football activities during Ramadan are sufficient. The increased match injury among non-Muslims during and 2 months post-Ramadan may suggest less effective coping strategies.

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.

Match injury rates in professional soccer vary with match result, match venue, and type of competition

BACKGROUND

Player activities in soccer matches are influenced by the match result and match venue. It is not known whether injury rates are influenced by these factors.

PURPOSE

To investigate whether there are associations between injury rates and the match result, venue, and type of competition in male soccer.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Twenty-six professional clubs from 10 countries were followed prospectively during 9 seasons (2001-2002 to 2009-2010). All matches, and injuries occurring in these matches, were registered by the team's medical staff. An injury was registered if it resulted in player absence from training or matches. Information about match result, venue, and type of competition for all reported matches was gathered by the authors from online databases. Injury rates in matches with varying match characteristics were compared by use of generalized estimating equations. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 2738 injuries during 6010 matches were registered. There were no associations between odds of 1 injury occurrence and match result or type of competition, whereas the odds were decreased in matches played away compared with home matches (OR, 0.89; 95% CI, 0.80-0.99). The odds of 2 or more injury occurrences in a match were increased in matches resulting in a draw (OR, 1.39; 95% CI, 1.15-1.69) or loss (OR, 1.66; 95% CI, 1.38-1.98) compared with matches won and were decreased in other cup matches compared with league matches (OR, 0.57; 95% CI, 0.39-0.84) and in matches played away compared with home matches (OR, 0.70; 95% CI, 0.60-0.82). Finally, injuries with more than 1 week's absence occurred more frequently in Champions League matches compared with league matches both for matches with 1 injury (OR, 1.26; 95% CI, 1.09-1.45) and matches with 2 or more injuries (OR, 1.57; 95% CI, 1.13-2.20).

CONCLUSION

The odds of 2 or more injury occurrences in professional soccer were higher in matches resulting in a loss or a draw compared with a win, whereas the odds of injury occurrences were lower in matches played away compared with home matches. The rate of moderate and severe injuries increased with the importance of the match.

Fewer ligament injuries but no preventive effect on muscle injuries and severe injuries: an 11-year follow-up of the UEFA Champions League injury study

BACKGROUND

Limited information is available on the variation in injury rates over multiple seasons of professional football.

AIM

To analyse time-trends in injury characteristics of male professional football players over 11 consecutive seasons.

METHODS

A total of 1743 players comprising 27 teams from 10 countries were followed prospectively between 2001 and 2012. Team medical staff recorded individual player exposure and time loss injuries.

RESULTS

A total of 8029 time loss injuries were recorded. The match unavailability due to injury was 14% and constant over the study period. On average, a player sustained two injuries per season, resulting in approximately 50 injuries per team and season. The ligament injury rate decreased during the study period (R(2)=0.608, b=-0.040, 95% CI -0.065 to -0.016, p=0.005), whereas the rate of muscle injury (R(2)=0.228, b=-0.013, 95% CI -0.032 to 0.005, p=0.138) and severe injury (R(2)=0.141, b=0.015, 95% CI -0.013 to 0.043, p=0.255) did not change over the study period. In addition, no changes in injury rates over the 11-year period were found for either training (R(2)=0.000, b=0.000, 95% CI -0.035 to 0.034, p=0.988) or match play (R(2)=0.282, b=-0.015, 95% CI -0.032 to 0.003, p=0.093).

CONCLUSIONS

The injury rate has decreased for ligament injuries over the last 11 years, but overall training, match injury rates and the rates of muscle injury and severe injury remain high.

Recurrence of Achilles tendon injuries in elite male football players is more common after early return to play: an 11-year follow-up of the UEFA Champions League injury study

BACKGROUND

There is limited information about Achilles tendon disorders in professional football.

AIMS

To investigate the incidence, injury circumstances, lay-off times and reinjury rates of Achilles tendon disorders in male professional football.

METHODS

A total of 27 clubs from 10 countries and 1743 players have been followed prospectively during 11 seasons between 2001 and 2012. The team medical staff recorded individual player exposure and time-loss injuries.

RESULTS

A total of 203 (2.5% of all injuries) Achilles tendon disorders were registered. A majority (96%) of the disorders were tendinopathies, and nine were partial or total ruptures. A higher injury rate was found during the preseason compared with the competitive season, 0.25 vs 0.18/1000 h (rate ratio (RR) 1.4, 95% CI 1.1 to 2.0; p=0.027). The mean lay-off time for Achilles tendinopathies was 23±37 (median=10, Q1=4 and Q3=24) days, while a rupture of the Achilles tendon, on average, caused 161±65 (median=169, Q1=110 and Q3=189) days of absence. Players with Achilles tendon disorders were significantly older than the rest of the cohort, with a mean age of 27.2±4 years vs 25.6±4.6 years (p<0.001). 27% of all Achilles tendinopathies were reinjuries. A higher reinjury risk was found after short recovery periods (31%) compared with longer recovery periods (13%) (RR 2.4, 95% CI 2.1 to 2.8; p<0.001).

CONCLUSIONS

Achilles tendon disorders account for 3.8% of the total lay-off time and are more common in older players. Recurrence is common after Achilles tendinopathies and the reinjury risk is higher after short recovery periods.

The Nordic Football Injury Audit: higher injury rates for professional football clubs with third-generation artificial turf at their home venue

BACKGROUND

Previously, no difference in acute injury rate has been found when playing football on artificial turf (AT) compared with natural grass (NG).

AIM

To compare acute injury rates in professional football played on AT and NG at the individual player level; and to compare, at club level, acute and overuse injury rates between clubs that have AT at their home venue (AT clubs) and clubs that have NG (NG clubs).

METHODS

32 clubs (AT, n=11; NG, n=21) in the male Swedish and Norwegian premier leagues were followed prospectively during the 2010 and 2011 seasons. Injury rate was expressed as the number of time loss injuries/1000 h and compared with rate ratio (RR) and 99% CI.

RESULTS

No statistically significant differences were found in acute injury rates on AT compared with NG during match play (RR 0.98, 99% CI 0.79 to 1.22) or training (RR 1.14, 99% CI 0.86 to 1.50) when analysing at the individual player level. When analysing at the club level, however, AT clubs had a significantly higher acute training injury rate (RR 1.31, 99% CI 1.04 to 1.63) and overuse injury rate (RR 1.38, 99% CI 1.14 to 1.65) compared with NG clubs.

CONCLUSIONS

At the individual player level, no significant differences were found in acute injury rates when playing on AT compared with NG. However, clubs with AT at their home venue had higher rates of acute training injuries and overuse injuries compared with clubs that played home matches on NG.

Lower injury rates for newcomers to professional soccer: a prospective cohort study over 9 consecutive seasons

BACKGROUND

No study has investigated whether newcomers to professional soccer have a different injury rate than established players.

PURPOSE

The primary objective was to investigate whether being a newcomer to professional soccer influences injury rates. The secondary objective was to evaluate whether playing position and player age influence injury rates.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Twenty-six soccer clubs, with 1401 players, were followed prospectively over 9 consecutive seasons between 2001 and 2010. Club medical staff recorded time-loss injuries and soccer exposure on an individual level. Cox regression analyses were used to evaluate associations between time-loss injuries and time in professional soccer, playing position, and age.

RESULTS

In total, 6140 injuries and 797,389 hours of exposure were registered. A decreased general injury rate was observed for newcomers (n = 116) compared with established players (n = 3091) (hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.61-0.99). In contrast, newcomers had a higher rate of fractures (rate ratio [RR], 1.77; 95% CI, 1.05-2.97), especially stress-related bone injuries (RR, 2.68; 95% CI, 1.08-6.69). Using goalkeepers as a reference, all outfield playing positions had significantly higher adjusted injury rates: defenders with an HR of 1.91 (95% CI, 1.64-2.24), midfielders with an HR of 1.78 (95% CI, 1.53-2.07), and forwards with an HR of 1.82 (95% CI, 1.55-2.14). Using players aged ≤21 years as a reference, the overall adjusted injury rate increased with age, with a peak injury rate among players aged 29 to 30 years (HR, 1.44; 95% CI, 1.24-1.68).

CONCLUSION

Newcomers to professional soccer had a lower general injury rate than established players but a higher rate of stress-related bone injuries. Being a goalkeeper was associated with lower injury rates than all outfield playing positions. Injury rates increased with age, a pattern that persisted after adjusting for playing position and match exposure.

Return to play after thigh muscle injury in elite football players: implementation and validation of the Munich muscle injury classification

Background

Owing to the complexity and heterogeneity of muscle injuries, a generally accepted classification system is still lacking.

Aims

To prospectively implement and validate a novel muscle injury classification and to evaluate its predictive value for return to professional football.

Methods

The recently described Munich muscle injury classification was prospectively evaluated in 31 European professional male football teams during the 2011/2012 season. Thigh muscle injury types were recorded by team medical staff and correlated to individual player exposure and resultant time-loss.

Results

In total, 393 thigh muscle injuries occurred. The muscle classification system was well received with a 100% response rate. Two-thirds of thigh muscle injuries were classified as structural and were associated with longer lay-off times compared to functional muscle disorders (p<0.001). Significant differences were observed between structural injury subgroups (minor partial, moderate partial and complete injuries) with increasing lay-off time associated with more severe structural injury. Median lay-off time of functional disorders was 5–8 days without significant differences between subgroups. There was no significant difference in the absence time between anterior and posterior thigh injuries.

Conclusions

The Munich muscle classification demonstrates a positive prognostic validity for return to play after thigh muscle injury in professional male football players. Structural injuries are associated with longer average lay-off times than functional muscle disorders. Subclassification of structural injuries correlates with return to play, while subgrouping of functional disorders shows less prognostic relevance. Functional disorders are often underestimated clinically and require further systematic study.

Injury surveillance in the World Football Tournaments 1998-2012

BACKGROUND

International sports bodies should protect the health of their athletes, and injury surveillance is an important pre-requisite for injury prevention. The Fédération International de Football Association (FIFA) has systematically surveyed all football injuries in their tournaments since 1998.

AIMS

Analysis of the incidence, characteristics and changes of football injury during international top-level tournaments 1998-2012.

METHODS

All newly incurred football injuries during the FIFA tournaments and the Olympic Games were reported by the team physicians on a standardised injury report form after each match. The average response rate was 92%.

RESULTS

A total of 3944 injuries were reported from 1546 matches, equivalent to 2.6 injuries per match. The majority of injuries (80%) was caused by contact with another player, compared with 47% of contact injuries by foul play. The most frequently injured body parts were the ankle (19%), lower leg (16%) and head/neck (15%). Contusions (55%) were the most common type of injury, followed by sprains (17%) and strains (10%). On average, 1.1 injuries per match were expected to result in absence from a match or training. The incidence of time-loss injuries was highest in the FIFA World Cups and lowest in the FIFA U17 Women's World Cups. The injury rates in the various types of FIFA World Cups had different trends over the past 14 years.

CONCLUSIONS

Changes in the incidence of injuries in top-level tournaments might be influenced by the playing style, refereeing, extent and intensity of match play. Strict application of the Laws of the Games is an important means of injury prevention.

The UEFA injury study: 11-year data concerning 346 MCL injuries and time to return to play

BACKGROUND

Medial collateral ligament (MCL) injury is the most common knee ligament injury in professional football.

AIM

To investigate the rate and circumstances of MCL injuries and development over the past decade.

METHODS

Prospective cohort study, in which 27 professional European teams were followed over 11 seasons (2001/2002 to 2011/2012). Team medical staffs recorded player exposure and time loss injuries. MCL injuries were classified into four severity categories. Injury rate was defined as the number of injuries per 1000 player-hours.

RESULTS

346 MCL injuries occurred during 1 057 201 h (rate 0.33/1000 h). The match injury rate was nine times higher than the training injury rate (1.31 vs 0.14/1000 h, rate ratio 9.3, 95% CI 7.5 to 11.6, p<0.001). There was a significant average annual decrease of approximately 7% (p=0.023). The average lay-off was 23 days, and there was no difference in median lay-off between index injuries and reinjuries (18 vs 13, p=0.20). Almost 70% of all MCL injuries were contact-related, and there was no difference in median lay-off between contact and non-contact injuries (16 vs 16, p=0.74).

CONCLUSIONS

This largest series of MCL injuries in professional football suggests that the time loss from football for MCL injury is 23 days. Also, the MCL injury rate decreased significantly during the 11-year study period.

Fifth metatarsal fractures among male professional footballers: a potential career-ending disease

BACKGROUND

There is little information about Metatarsal Five (MT-5) fractures for specific sports.

OBJECTIVE

To study the occurrence, the imaging characteristics, the lay-off times and healing problems of MT-5 fractures among male footballers.

METHODS

Sixty-four European elite teams were monitored from 2001 to 2012. x-Rays were collected and classified by the Torg criteria.

RESULTS

Of 13 754 injuries, 0.5% (67) proved to be MT-5 fractures. Their incidence was 0.04 injuries/1000 h of exposure. A team of 25 players might thus expect an MT-5 fracture every fifth season. Of these fractures, 67% (38) were primary and 33% were refractures. One of the 38 primary fractures was an avulsion of the tuberosity; all the others (97%) located towards the base. In total, 32% of the players with MT-5 fracture were younger than 21 years, 40% of the fractures occurred during the preseason and 45% of the players had prodromal symptoms. In total, 54% of the initial x-rays were classified as Torg type II (stress fractures), and 46% were classified as Torg type I (acute type). After surgical treatment the fractures healed faster, compared with conservative treatment (75% vs 33%, p<0.05). There was no significant difference in lay-off days between players that had been operated, and those that had not (80 vs 74 days, p=0.67).

CONCLUSIONS

The majority of MT-5 fractures are stress fractures, and mainly occur among young players. There are frequent healing problems, which might be explained by the stress nature of the injury. After surgery there are less healing problems, compared with those in conservative treatment.

Results of 2 decades of injury surveillance and public release of data in the Australian Football League

BACKGROUND

Injuries are common in all professional football codes (including soccer, rugby league and union, American football, Gaelic football, and Australian football).

PURPOSE

To report the epidemiology of injuries in the Australian Football League (AFL) from 1992-2012 and to identify changes in injury patterns during that period.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

The AFL commenced surveying injuries in 1992, with all teams and players included since 1996. An injury was defined as "any physical or medical condition that causes a player to miss a match in the regular season or finals (playoffs)." Administrative records of injury payments (which are compulsory as part of salary cap compliance) to players who do not play matches determined the occurrence of an injury. The seasonal incidence was measured in units of new injuries per club (of 40 players) per season (of 22 matches).

RESULTS

There were 4492 players listed over the 21-year period who suffered 13,606 new injuries/illnesses and 1965 recurrent injuries/illnesses, which caused 51,919 matches to be missed. The lowest seasonal incidence was 30.3 new injuries per club per season recorded in 1993, and the highest was 40.3 recorded in 1998. The injury prevalence (missed matches through injury per club per season) varied from a low of 116.3 in 1994 to a high of 157.1 in 2011. The recurrence rate of injuries was highest at 25% in 1992 and lowest at 9% in 2012 and has steadily fallen across the 21 years (P < .01). The most frequent and prevalent injury was hamstring strain (average of 6 injuries per club per season, resulting in 20 missed matches per club per season; recurrence rate, 26%), although the rate of hamstring injuries has fallen in the past 2 seasons after a change to the structure of the interchange bench (P < .05). The rate of knee posterior cruciate ligament injuries fell in the years after a rule change to prevent knee-to-knee collisions in ruckmen (P < .01).

CONCLUSION

Annual public reporting (by way of media release and reports available freely online) of injury rates, using units easily understood by laypeople, has been well received. It has also paved the way for rule changes with the primary goal of improving player safety.

Risk factors for lower extremity muscle injury in professional soccer: the UEFA Injury Study

BACKGROUND

Muscle injury is the most common injury type in professional soccer players. Despite this, risk factors for common lower extremity injuries remain elusive.

PURPOSE

To evaluate the effects of various player- and match-related risk factors on the occurrence of lower extremity muscle injury in male professional soccer.

STUDY DESIGN

Cohort study; level of evidence, 2.

METHODS

Between 2001 and 2010, 26 soccer clubs (1401 players) from 10 European countries participated in the study. Individual player exposure and time loss muscle injuries in the lower extremity were registered prospectively by the club medical staffs during 9 consecutive seasons. Hazard ratios (HRs) were calculated for player-related factors from simple and multiple Cox regression, and odds ratios (ORs) were calculated for match-related variables from simple and multiple logistic regression, presented with 95% confidence intervals (CIs).

RESULTS

There were 2123 muscle injuries documented in the major lower extremity muscle groups: adductors (n = 523), hamstrings (n = 900), quadriceps (n = 394), and calf (n = 306). Injuries to the adductors (56%; P = .015) and quadriceps (63%; P< .001) were more frequent in the kicking leg. Multiple analysis indicated that having a previous identical injury in the preceding season increased injury rates significantly for adductor (HR, 1.40; 95% CI, 1.00-1.96), hamstring (HR, 1.40; 95% CI, 1.12-1.75), quadriceps (HR, 3.10; 95% CI, 2.21-4.36), and calf injuries (HR, 2.33; 95% CI, 1.52-3.57). Older players (above mean age) had an almost 2-fold increased rate of calf injury (HR, 1.93; 95% CI, 1.38-2.71), but no association was found in other muscle groups. Goalkeepers had reduced injury rates in all 4 muscle groups. Match play on away ground was associated with reduced rates of adductor (OR, 0.56; 95% CI, 0.43-0.73) and hamstring injuries (OR, 0.76; 95% CI, 0.63-0.92). Quadriceps injuries were more frequent during preseason, whereas adductor, hamstring, and calf injury rates increased during the competitive season.

CONCLUSION

Intrinsic factors found to increase muscle injury rates in professional soccer were previous injury, older age, and kicking leg. Injury rates varied during different parts of the season and also depending on match location.

Terminology and classification of muscle injuries in sport: the Munich consensus statement

Objective

To provide a clear terminology and classification of muscle injuries in order to facilitate effective communication among medical practitioners and development of systematic treatment strategies.

Methods

Thirty native English-speaking scientists and team doctors of national and first division professional sports teams were asked to complete a questionnaire on muscle injuries to evaluate the currently used terminology of athletic muscle injury. In addition, a consensus meeting of international sports medicine experts was established to develop practical and scientific definitions of muscle injuries as well as a new and comprehensive classification system.

Results

The response rate of the survey was 63%. The responses confirmed the marked variability in the use of the terminology relating to muscle injury, with the most obvious inconsistencies for the term strain. In the consensus meeting, practical and systematic terms were defined and established. In addition, a new comprehensive classification system was developed, which differentiates between four types: functional muscle disorders (type 1: overexertion-related and type 2: neuromuscular muscle disorders) describing disorders without macroscopic evidence of fibre tear and structural muscle injuries (type 3: partial tears and type 4: (sub)total tears/tendinous avulsions) with macroscopic evidence of fibre tear, that is, structural damage. Subclassifications are presented for each type.

Conclusions

A consistent English terminology as well as a comprehensive classification system for athletic muscle injuries which is proven in the daily practice are presented. This will help to improve clarity of communication for diagnostic and therapeutic purposes and can serve as the basis for future comparative studies to address the continued lack of systematic information on muscle injuries in the literature.

What are the new things

Consensus definitions of the terminology which is used in the field of muscle injuries as well as a new comprehensive classification system which clearly defines types of athletic muscle injuries.

Level of evidence

Expert opinion, Level V.

Prevention of acute knee injuries in adolescent female football players: cluster randomised controlled trial

OBJECTIVE

To evaluate the effectiveness of neuromuscular training in reducing the rate of acute knee injury in adolescent female football players.

DESIGN

Stratified cluster randomised controlled trial with clubs as the unit of randomisation.

SETTING

230 Swedish football clubs (121 in the intervention group, 109 in the control group) were followed for one season (2009, seven months).

PARTICIPANTS

4564 players aged 12-17 years (2479 in the intervention group, 2085 in the control group) completed the study.

INTERVENTION

15 minute neuromuscular warm-up programme (targeting core stability, balance, and proper knee alignment) to be carried out twice a week throughout the season.

MAIN OUTCOME MEASURES

The primary outcome was rate of anterior cruciate ligament injury; secondary outcomes were rates of severe knee injury (>4 weeks' absence) and any acute knee injury.

RESULTS

Seven players (0.28%) in the intervention group, and 14 (0.67%) in the control group had an anterior cruciate ligament injury. By Cox regression analysis according to intention to treat, a 64% reduction in the rate of anterior cruciate ligament injury was seen in the intervention group (rate ratio 0.36, 95% confidence interval 0.15 to 0.85). The absolute rate difference was -0.07 (95% confidence interval -0.13 to 0.001) per 1000 playing hours in favour of the intervention group. No significant rate reductions were seen for secondary outcomes.

CONCLUSIONS

A neuromuscular warm-up programme significantly reduced the rate of anterior cruciate ligament injury in adolescent female football players. However, the absolute rate difference did not reach statistical significance, possibly owing to the small number of events.

TRIAL REGISTRATION

Clinical trials NCT00894595.

Thigh muscle injuries in youth soccer: predictors of recovery

BACKGROUND

Participation in soccer at younger ages with attendant risk of muscle injury is increasing.

PURPOSE

To delineate patterns of thigh muscle injury and predictors of recovery in male youth soccer academy players.

STUDY DESIGN

Cohort study (prognosis); Level of evidence, 2.

METHODS

Forty-one English Premiership soccer academy squads (all male, aged 8-16 years) over a 5-year period comprising 12 306 player seasons were studied prospectively for pattern, mechanism, and outcome after thigh muscle injury. Event analysis was used to identify independent predictors of slow recovery.

RESULTS

A total of 1288 injuries were recorded representing an incidence (mean [SD]) of 0.42 (0.24) per thousand hours of training with a mean annual incidence of 0.52. Midfield players received the most injuries, followed by defense and attack positions. The quadriceps muscle group was most likely to be injured. There were 345 reinjuries (27%). Median time off for a primary injury was 13 days (interquartile range, 7-22 days) and 12 days (7-21 days) following a reinjury. Risk of such injury increased as the game progressed toward the end of the first half period (P = .028), and this risk persisted throughout the entire second half. There were 2 peaks of incidence (January and September). The percentage of the total for hamstring, adductor, and quadriceps injuries did not significantly change with player age. However, the proportion of injuries that were severe increased with age of player (t = 3.72, P = .010). Poor prognostic factors for recovery were hamstring injuries (z = 2.182, P = .029), contact injury (z = -3.137, P = .002), and older age (z = -2.2298, P = .022).

CONCLUSION

The risk for prolonged recovery from thigh muscle injury was found to increase with age of the player and contact mechanism. The risk of injury increased toward the end of the first half, and this risk persisted throughout the second half. Delayed recovery was significantly associated with a hamstring muscle injury, first injury, and contact mechanism. This study, for the first time, allows identification of youth male soccer players at high-risk for prolonged symptoms after thigh muscle injury.

Injury incidence in a spanish sub-elite professional football team: a prospective study during four consecutive seasons

The aim of this study was to investigate the injury incidence and injury characteristics of a Spanish sub-elite professional football team during four consecutive seasons. A team was followed prospectively from the season 2003-2004 to 2006-2007 and individual player exposure and time loss injuries were recorded during all club training sessions and matches. A total of 313 time-loss injuries were recorded. The mean injury incidence was 10.9 injuries/1000 hours (5.2 injuries/1000 training hours and 44.1 injuries/1000 match hours). The injury incidence during competitive matches was higher (p < 0.001) than in friendly matches (55.8 vs. 22.6 injuries/1000 hours). The incidence of major injuries (>28 days absence) was 0.4 injuries/1000 hours. The thigh was the most commonly (35%) injured region and caused 29% of all competitive match absence. Muscle injuries in the four main groups of the lower limbs (hamstrings, adductors, quadriceps and calf muscles) caused 43% of competitive match unavailability. The results of this study show that the risk to sustain a major injury in the course of the season was low for sub- elite footballers in comparison to elite players. Thigh strains were the first cause of absence in competition due to injury. Key pointsThe incidence of major injuries (absence greater than 4 weeks) was lower in a Spanish sub-elite football team than in elite European teams.The risk of sustaining an injury was 2.5 fold higher (p < 0.001) in official than in friendly matches.Lower limb muscular (hamstrings, quadriceps, hip adductors and calf muscles) and joint (knee and ankle) injuries were the main causes of match unavailability.

Regional differences in injury incidence in European professional football

The objective of this study was to investigate regional differences in injury incidence in men's professional football in Europe. A nine-season prospective cohort study was carried out between 2001-2002 and 2009-2010 involving 1357 players in 25 teams from nine countries. Teams were categorized into different regions according to the Köppen-Geiger climate classification system. Teams from the northern parts of Europe (n = 20) had higher incidences of injury overall [rate ratio 1.12, 95% confidence interval (CI) 1.06 to 1.20], training injury (rate ratio 1.16, 95% CI 1.05 to 1.27), and severe injury (rate ratio 1.29, 95% CI 1.10 to 1.52), all statistically significant, compared to teams from more southern parts (n = 5). In contrast, the anterior cruciate ligament injury incidence was lower in the northern European teams with a statistically significant difference (rate ratio 0.43, 95% CI 0.25 to 0.77), especially for noncontact anterior cruciate ligament injury (rate ratio 0.19, 95% CI 0.09 to 0.39). In conclusion, this study suggests that there are regional differences in injury incidence of European professional football. However, further studies are needed to identify the underlying causes.

English Premiership Academy knee injuries: lessons from a 5 year study

This study addresses the epidemiology of knee injuries in adolescent males. Data were collected prospectively from 41 Premiership soccer academies over a 5 year period from July 2000 to June 2005. A total of 12,306 player seasons were registered in the U9 to the U16 age categories with a total of 1750 recordable injuries specific to the knee joint. There was a mean incidence of 0.71 (95% confidence interval ± 0.05) knee injuries per player per year, and a median of 17 (inter-quartile range 9-38) training days and 2 (inter-quartile range 1-4) matches missed per knee injury. Knee injuries were found to be most common in the 14-16 year age group. Six hundred and nine (35% of total) injuries were classed as severe resulting in more than 28 days' absence. Injuries were more likely to be sustained in a competitive or match-play environment (862 or 52%) than in training (796 or 48%), and a non-contact mechanism was implicated in 823 (55%) of recorded cases. Peaks in injury numbers were seen in early season and subsequent to the winter break. Sprain was the most common diagnosis recorded, with the medial collateral ligament affected in 23% of all knee injuries. Knee injuries are common in elite youth footballers. In this uninsured age group, it could be argued that earlier medical intervention may reduce long-term damage to the immature skeleton.

Epidemiology of patellar tendinopathy in elite male soccer players

BACKGROUND

Patellar tendinopathy is common among athletes in jumping sports and in sports with prolonged repetitive stress of the knee extensor apparatus. The epidemiology in soccer is not well described.

PURPOSE

This study was undertaken to investigate and describe the epidemiology of patellar tendinopathy in elite male soccer players and evaluate potential risk factors.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Between 2001 and 2009, the authors followed 51 European elite soccer clubs (2229 players) from 3 different cohorts: the Swedish First League cohort (SWE) and Union of European Football Associations (UEFA) Champions League cohort (UCL), both playing on natural grass; and the Artifical Turf cohort (ART), playing on third-generation artificial turf. Individual player exposure in training and matches and time-loss injuries were recorded.

RESULTS

In total, 137 patellar tendinopathies were recorded, comprising 1.5% of all injuries and corresponding to an incidence of 0.12 injuries/1000 hours. Each season, 2.4% of players were affected, with most injuries (61%) resulting in absence up to 1 week or less. Twenty percent of tendinopathies were recurrent complaints. No significant difference in season prevalence (odds ratio [OR], 0.93; 95% confidence interval [CI], 0.60-1.44; P = .74) or incidence (rate ratio [RR] 1.20; 95% CI, 0.82-1.75; P = .36) was observed between teams playing on artificial turf and natural grass, respectively. Multivariate logistic regression showed that a high total exposure hours (OR, 1.02 per 10-hour increase; 95% CI, 1.00-1.04; P = .033) was a significant risk factor for patellar tendinopathy, and increased body mass was borderline significant (OR, 1.15 per 5-kg increase; 95% CI, 1.00-1.33; P = .055). In addition, 2 acute partial tendon ruptures were recorded, but no total rupture.

CONCLUSION

Although mainly mild in nature, patellar tendinopathy is a fairly common condition in elite soccer and the recurrence rate is high. Exposure to artificial turf did not increase the prevalence or incidence of injury. High total amount of exposure was identified as a risk factor for patellar tendinopathy.

Effects of footwear on comfort and injury in professional rugby league

The aim of this study was to determine the effectiveness of a tailored footwear programme on lower-limb comfort in professional rugby league players. The study was conducted over 30 weeks and involved two professional teams (n = 59 players) from the Australian National Rugby League competition. One team was assigned to a footwear programme (intervention), while players from the control group continued usual practices of self-selected footwear. The tailored footwear programme consisting of player education, prescription of footwear, and frequent rotation of footwear resulted in a lower incidence of injury and higher comfort ratings. The intervention group had fewer lower-limb injuries (P = 0.005; Cohen d = 0.72) and higher comfort ratings (P < 0.001, Cohen d = 1.24) than the control group. Specifically, the intervention group reported a lower incidence of poor comfort events (mean = 3.8, s = 2.7) than the control group (mean = 7.9, s = 3.7). Observations also included fewer time loss events in the intervention (mean = 6.3, s = 4.8) than the control group (mean = 11.0, s = 6.3) and reduced injuries per 1000 h in the intervention (24.79/1000) than the control group (30.76/1000). These findings should help medical advisers improve footwear comfort in sportspeople and so reduce the incidence of related injuries.

A four-season prospective study of muscle strain reoccurrences in a professional football club

The aim of this investigation was to characterise muscle strain reinjuries and examine their impact on playing resources in a professional football club. Muscle strains and reoccurrences were prospectively diagnosed over four seasons in first-team players (n = 46). Altogether, 188 muscle strains were diagnosed with 44 (23.4%) of these classed as reinjuries, leading to an incidence of 1.32 strain reoccurrences per 1,000 hours exposure (95% Confidence Interval [CI], 0.93-1.71). The incidence of recurrent strains was higher in match-play compared with training (4.51, 95% CI, 2.30-6.72 vs 0.94, 95% CI, 0.59-1.29). Altogether, 50.0% of players sustained at least 1 reoccurrence of a muscle strain, leading to approximately 3 days lost and 0.4 matches missed per player per season. The incidence of recurrent strains was highest in centre-forwards (2.15, 95% CI, 1.06-3.24), peaked in May (3.78, 95% CI, 0.47-7.09), and mostly affected the hamstrings (38.6% of all reoccurrences). Mean layoff for nonreoccurrences and recurrences was similar: approximately 7.5 days. These results provide greater insight into the extent of the problem of recurrent muscle strains in professional football.

Epidemiology of muscle injuries in professional football (soccer)

BACKGROUND

Muscle injuries constitute a large percentage of all injuries in football.

PURPOSE

To investigate the incidence and nature of muscle injuries in male professional footballers.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Fifty-one football teams, comprising 2299 players, were followed prospectively during the years 2001 to 2009. Team medical staff recorded individual player exposure and time-loss injuries. The first-team squads of 24 clubs selected by the Union of European Football Associations as belonging to the best European teams, 15 teams of the Swedish First League, and another 15 European teams playing their home matches on artificial turf pitches were included. A muscle injury was defined as "a traumatic distraction or overuse injury to the muscle leading to a player being unable to fully participate in training or match play."

RESULTS

In total, 2908 muscle injuries were registered. On average, a player sustained 0.6 muscle injuries per season. A squad of 25 players can thus expect about 15 muscle injuries per season. Muscle injuries constituted 31% of all injuries and caused 27% of the total injury absence. Ninety-two percent of all muscle injuries affected the 4 major muscle groups of the lower limbs: hamstrings (37%), adductors (23%), quadriceps (19%), and calf muscles (13%). Sixteen percent of the muscle injuries were reinjuries. These reinjuries caused significantly longer absences than did index injuries. The incidence of muscle injury increased with age. When separated into different muscle groups, however, an increased incidence with age was found only for calf muscle injuries and not for hamstring, quadriceps, or hip/groin strains.

CONCLUSION

Muscle injuries are a substantial problem for players and their clubs. They constitute almost one third of all time-loss injuries in men's professional football, and 92% of all injuries affect the 4 big muscle groups in the lower limbs.

Injury risk factors in young soccer players detected by a multivariate survival model

Soccer is a popular game practiced all around the world by teenagers. However, despite being a relatively safe sport, muscle-strain injuries during competitive matches are common compared to other team-sports. Few studies, to date, have investigated risk factors for soccer injuries using a multivariate survival model (e.g., Cox regression). The aim of this study was to use a multivariate survival model to investigate factors associated with an increased risk of thigh muscle strains, in young soccer players. A multivariate Cox regression was used to evaluate survival probability predictors for thigh muscle strains. 84 young male soccer players (16.4 ± 1.6 years) were followed for a season. Baseline tests were performed for body size, body composition, endurance, flexibility, and jump height from both a static position (SJ), and with a countermovement (CMJ); the percentage difference between the two types of jumps was also calculated (ΔJH). Cox regression result (hazard ratio; C.I. 95%) showed that: previous injuries (2.80; 1.19-6.54), ΔJH (0.79; 0.71-0.87), and stature (1.17; 1.06-1.25) were significantly correlated to thigh-strain survival probability. This study confirms that previous injuries are an important risk factor. However, we also report that a negative ΔJH and an elevated stature increased the probability of thigh strain. This could be explained by poor player coordination, influencing jumping ability, which may be even more evident in tall young players.

Prevalence and etiological factors of sport-related groin injuries in top-level soccer compared to non-contact sports

PURPOSE

Groin injuries and chronic pain are relatively common in soccer and other contact sports. Our aim was to define the gender-related frequency of both acute and chronic groin injuries in soccer compared to non-contact endurance sports.

METHODS

A 12-month study of 613 professional athletes was conducted in 2006. Premier league soccer players (77 males and 90 females) answered retrospectively 70 multi-choice questions of sport injuries. Factors related to groin injuries were compared with corresponding data of elite-level swimmers (n = 154), long-distance runners (n = 143) and cross-country skiers (n = 149).

RESULTS

In soccer, 125/167 players had 375 injuries (274 acute and 101 overuse injuries) and the number of acute injuries were 146/274 (53%) in males and 128/274 (47%) in females (p = 0.368). Acute groin injury was reported in 15/167 (9.0%) of elite soccer players compared to 3/154 (2.0%) in swimmers (p = 0.006) and 1.4% in both long-distance running (n = 2) and skiing (n = 2, p = 0.003). Male soccer players had acute groin injuries nearly three times more frequently than females. Chronic persistent groin pain was found in only one male and two female soccer players and no athletes in endurance sports.

CONCLUSIONS

Almost every tenth soccer player had an acute groin injury. Long-standing groin pain was not frequent in soccer and it was not found in non-contact endurance sport at the elite-level.

Anterior cruciate ligament injury in elite football: a prospective three-cohort study

Anterior cruciate ligament (ACL) injury causes long lay-off time and is often complicated with subsequent new knee injury and osteoarthritis. Female gender is associated with an increased ACL injury risk, but few studies have adjusted for gender-related differences in age although female players are often younger when sustaining their ACL injury. The objective of this three-cohort study was to describe ACL injury characteristics in teams from the Swedish men's and women's first leagues and from several European men's professional first leagues. Over a varying number of seasons from 2001 to 2009, 57 clubs (2,329 players) were followed prospectively and during this period 78 ACL injuries occurred (five partial). Mean age at ACL injury was lower in women compared to men (20.6 ± 2.2 vs. 25.2 ± 4.5 years, P = 0.0002). Using a Cox regression, the female-to-male hazard ratio (HR) was 2.6 (95% CI 1.4-4.6) in all three cohorts studied and 2.6 (95% CI 1.3-5.3) in the Swedish cohorts; adjusted for age, the HR was reduced to 2.4 (95% CI 1.3-4.2) and 2.1 (95% CI 1.0-4.2), respectively. Match play was associated with a higher ACL injury risk with a match-to-training ratio of 20.8 (95% CI 12.4-34.8) and 45 ACL injuries (58%) occurred due to non-contact mechanisms. Hamstrings grafts were used more often in Sweden than in Europe (67 vs. 34%, P = 0.028), and there were no differences in time to return to play after ACL reconstruction between the cohorts or different grafts. In conclusion, this study showed that the ACL injury incidence in female elite footballers was more than doubled compared to their male counterparts, but also that they were significantly younger at ACL injury than males. These findings suggest that future preventive research primarily should address the young female football player.

The Brazilian Football Association (CBF) model for epidemiological studies on professional soccer player injuries

OBJECTIVE

This study aims to establish a national methodological model for epidemiological studies on professional soccer player injuries and to describe the numerous relevant studies previously published on this topic.

INTRODUCTION

The risk of injury in professional soccer is high. However, previous studies of injury risk in Brazil and other countries have been characterized by large variations in study design and data collection methods as well as definitions of injury, standardized diagnostic criteria, and recovery times.

METHODS

A system developed by the Union of European Football for epidemiological studies on professional soccer players is being used as a starting point to create a methodological model for the Brazilian Football Association. To describe the existing studies on professional soccer player injuries, we developed a search strategy to identify relevant epidemiological studies. We included the Latin American and Caribbean Center on Health Sciences and Medline databases in our study.

RESULTS

We considered 60 studies from Medline and 16 studies from the Latin American and Caribbean Center on Health Sciences in the final analysis. Twelve studies were selected for final inclusion in this review: seven from the Latin American and Caribbean Center on Health Sciences and five from Medline. We identified a lack of uniformity in the study design, data collection methods, injury definitions, standardized diagnostic criteria, and the definition of recovery time. Based on the information contained within these articles, we developed a model for epidemiological studies for the Brazilian Football Association.

CONCLUSIONS

There is no uniform model for epidemiological studies of professional soccer injuries. Here, we propose a novel model to be applied for epidemiological studies of professional soccer player injuries in Brazil and throughout the world.

Overuse injuries in professional road cyclists

BACKGROUND

Little epidemiological information exists on overuse injuries in elite road cyclists. Anecdotal reports indicate anterior knee pain and lower back pain may be common problems.

PURPOSE

This study was conducted to register overuse injuries among professional road cyclists with special focus on anterior knee and lower back pain.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

We attended training camps of 7 professional teams and interviewed 109 of 116 cyclists (94%) on overuse injuries they had experienced in the previous 12 months. Injuries that required attention from medical personnel or involved time loss from cycling were registered. Additional information on anterior knee pain and lower back pain was collected using specific questionnaires.

RESULTS

A total of 94 injuries were registered; 45% were in the lower back and 23% in the knee. Twenty-three time-loss injuries were registered-57% in the knee, 22% in the lower back, and 13% in the lower leg. Fifty-eight percent of all cyclists had experienced lower back pain in the previous 12 months, and 41% of all cyclists had sought medical attention for it. Thirty-six percent had experienced anterior knee pain and 19% had sought medical attention for it. Few cyclists had missed competitions because of pain in the lower back (6%) or anterior knee (9%).

CONCLUSION

Lower back pain and anterior knee pain were the most prevalent overuse injuries, with knee injuries most likely to cause time loss and lower back pain causing the highest rates of functional impairment and medical attention.

CLINICAL RELEVANCE

Future efforts to prevent overuse injuries in competitive cyclists should focus on lower back pain and anterior knee pain.

The Prevention of Sport Injury: An Analysis of 12 000 Published Manuscripts

OBJECTIVE

To identify the nature and extent of research in sport injury prevention with respect to 3 main categories: (1) training, (2) equipment, and (3) rules and regulations.

DATA SOURCES

We searched PubMed, CINAHL, Web of Science, Embase, and SPORTDiscus to retrieve all sports injury prevention publications. Articles were categorized according to the translating research into injury prevention practice model.

RESULTS

We retrieved 11 859 articles published since 1938. Fifty-six percent (n = 6641) of publications were nonresearch (review articles and editorials). Publications documenting incidence (n = 1354) and etiology (n = 2558) were the most common original research articles (33% of total). Articles reporting preventive measures (n = 708) and efficacy (n = 460) were less common (10% of the total), and those investigating implementation (n = 162) and effectiveness (n = 32) were rare (1% of total). Six hundred seventy-seven studies focused on equipment and devices to protect against injury, whereas 551 investigated various forms of physical training related to injury prevention. Surprisingly, publications studying changes in rules and regulations aimed at increasing safety and reducing injuries were rare (<1%; n = 63) with a peak of only 20 articles over the most recent 5-year period and an average of 10 articles over the preceding 5-year blocks of time.

CONCLUSIONS

Only 492 of 11 859 publications actually assessed the effectiveness of sports injury prevention interventions or their implementation. Research in the area of regulatory change is underrepresented and might represent one of the greatest opportunities to prevent injury.

Revision, uptake and coding issues related to the open access Orchard Sports Injury Classification System (OSICS) versions 8, 9 and 10.1

The Orchard Sports Injury Classification System (OSICS) is one of the world's most commonly used systems for coding injury diagnoses in sports injury surveillance systems. Its major strengths are that it has wide usage, has codes specific to sports medicine and that it is free to use. Literature searches and stakeholder consultations were made to assess the uptake of OSICS and to develop new versions. OSICS was commonly used in the sports of football (soccer), Australian football, rugby union, cricket and tennis. It is referenced in international papers in three sports and used in four commercially available computerised injury management systems. Suggested injury categories for the major sports are presented. New versions OSICS 9 (three digit codes) and OSICS 10.1 (four digit codes) are presented. OSICS is a potentially helpful component of a comprehensive sports injury surveillance system, but many other components are required. Choices made in developing these components should ideally be agreed upon by groups of researchers in consensus statements.

Incidence, severity, aetiology and type of neck injury in men's amateur rugby union: a prospective cohort study

Background

There is a paucity of epidemiological data on neck injury in amateur rugby union populations. The objective of this study was to determine the incidence, severity, aetiology and type of neck injury in Australian men's amateur rugby union.

Methods

Data was collected from a cohort of 262 participants from two Australian amateur men's rugby union clubs via a prospective cohort study design. A modified version of the Rugby Union Injury Report Form for Games and Training was used by the clubs physiotherapist or chiropractor in data collection.

Results

The participants sustained 90 (eight recurrent) neck injuries. Exposure time was calculated at 31143.8 hours of play (12863.8 hours of match time and 18280 hours of training). Incidence of neck injury was 2.9 injuries/1000 player-hours (95%CI: 2.3, 3.6). As a consequence 69.3% neck injuries were minor, 17% mild, 6.8% moderate and 6.8% severe. Neck compression was the most frequent aetiology and was weakly associated with severity. Cervical facet injury was the most frequent neck injury type.

Conclusions

This is the first prospective cohort study in an amateur men's rugby union population since the inception of professionalism that presents injury rate, severity, aetiology and injury type data for neck injury. Current epidemiological data should be sought when evaluating the risks associated with rugby union football.

Return to training and playing after posterior ankle arthroscopy for posterior impingement in elite professional soccer

BACKGROUND

Posterior ankle impingement syndrome (PAIS) was first described in ballet dancers but is increasingly being diagnosed in other sports. Operative treatment may be indicated when nonoperative measures have failed. Traditionally, operative treatment has involved an open approach; more recently, posterior ankle arthroscopy has been employed.

PURPOSE

This study was conducted to describe the factors that influence return to play in professional athletes after posterior ankle arthroscopy for posterior ankle impingement syndrome.

STUDY DESIGN

Case series; Level of evidence 4.

METHODS

A consecutive series of 28 elite professional soccer players who had clinically and radiologically diagnosed posterior ankle impingement syndrome that failed to respond to nonoperative treatment underwent posterior ankle arthroscopy for bony or soft tissue posterior ankle impingement syndrome over 5 years.

RESULTS

Of the 28 players, 27 were available for follow-up. Five had a diagnosis of soft tissue impingement and underwent debridement with flexor hallucis longus release, 13 had a symptomatic os trigonum that was excised arthroscopically, and 9 had removal of a bony avulsion fragment from the posterior ankle ligament complex. The mean length of time to return to training postoperatively was 34 days and return to playing was 41 days (range, 29-72 days). The duration of symptoms before surgery and excision of bony impingement were significantly correlated with the time to return to training and playing. There were no major complications and no reoperations at an average of 23 months of follow-up (range, 15-49 months).

CONCLUSION

Posterior ankle arthroscopy is safe and effective in the treatment of posterior ankle impingement syndrome in the elite soccer player, with return to training expected at an average of 5 weeks.

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.