Determination of future prevention strategies in elite track and field: analysis of Daegu 2011 IAAF Championships injuries and illnesses surveillance

Risk of Injuries in Paralympic Track and Field Differs by Impairment and Event Discipline: A Prospective Cohort Study at the London 2012 Paralympic Games

BACKGROUND

The incidence rates (IRs) and factors associated with injuries in the sport of Paralympic athletics (track and field) have not been comprehensively and prospectively studied.

PURPOSE

To determine injury IRs, characteristics of injuries, and associated factors in the sport of athletics at the London 2012 Paralympic Games.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 977 athletes competing in the sport of athletics were followed over a total 10-day competition period of the Paralympic Games. Daily injury data were obtained via 2 databases: (1) a custom-built, web-based injury and illness surveillance system (WEB-IISS), maintained by team medical personnel; and (2) the organizing committee database, maintained by medical providers in the medical stations operated by the London Organising Committee of the Olympic and Paralympic Games. Athlete impairment and event discipline were obtained via the International Paralympic Committee athlete database. IRs (injuries per 1000 athlete-days) by impairment, event discipline, sex, and age were examined.

RESULTS

The overall IR was 22.1 injuries per 1000 athlete-days (95% CI, 19.5-24.7). In track disciplines, ambulant athletes with cerebral palsy experienced a lower incidence of injuries (IR, 10.2; 95% CI, 4.2-16.2) when compared with ambulant athletes from other impairment categories. Athletes in seated throwing experienced a higher incidence of injuries (IR, 23.7; 95% CI, 17.5-30.0) when compared with athletes in wheelchair racing (IR, 10.6; 95% CI, 5.5-15.6). In both track and field disciplines, the majority of injuries did not result in time loss from competition or training. Ambulant athletes experienced the greatest proportion of injuries to the thigh (16.4% of all injuries; IR, 4.0), observed predominantly in track athletes. Wheelchair or seated athletes experienced the greatest proportion of injuries to the shoulder/clavicle (19.3% of all injuries; IR, 3.4), observed predominantly in field athletes.

CONCLUSION

This is the first prospective cohort study examining injury IRs and associated factors in the sport of athletics at the Paralympic Games. Injury patterns were specific to the event discipline and athlete impairment. The majority of injuries occurred to the thigh (ambulant athletes) or shoulder/clavicle (wheelchair or seated athletes) and did not result in time loss.

Injury and Illness Rates During Ultratrail Running

This study aimed to describe injury/illness rates in ultratrail runners competing in a 65-km race to build a foundation for injury prevention and help race organizers to plan medical provision for these events. Prospectively transcribed medical records were analysed for 77 athletes at the end of the race. Number of injuries/illnesses per 1 000 runners and per 1 000-h run, overall injury/illness rate and 90% confidence intervals and rates for major and minor illnesses, musculoskeletal injuries, and skin disorders were analysed. A total of 132 injuries/illnesses were encountered during the race. The overall injuries/illnesses were 1.9 per runner and 13.1 per 1 000-h run. Medical illnesses were the most prominent medical diagnoses encountered (50.3%), followed by musculoskeletal injuries (32.8%), and skin-related disorders (16.9%). Despite the ultra-long nature of the race, the majority of injuries/illnesses were minor in nature. Medical staff and runners should prepare to treat all types of injuries and illnesses, especially the fatigue arising throughout the course of an ultratrail run and injuries to the lower limbs. Future studies should attempt to systematically identify injury locations and mechanisms in order to better direct injury prevention strategies and plan more accurate medical care.

Methodological quality of the injury surveillance system used in international athletics championships

OBJECTIVES

Incidence and prevalence data obtained from injury surveillance studies could be biased by the response rate as well as by the completeness and quality of the reports. It therefore appears crucial to analyse the quality of the injury surveillance system itself and thereby validate the quality of the data. This study aimed to analyse the quality of and compliance with the injury surveillance system implemented during international athletics championships.

DESIGN

Prospective, epidemiological study.

METHODS

The national medical teams and the local organising committee physicians daily reported all injuries on a standardised injury report form during 14 international athletics championships from 2007 to 2015. The quality of the injury surveillance system was analysed following the guidelines laid down by the Centre for Disease Control and Prevention.

RESULTS

On average 41.7±17.4% (mean±standard deviation) of all registered countries participated in the injury surveillance project, accounting for a coverage of athletes of 79.5±10.2% of all registered athletes. Their medical staff returned 89.2±8.4% of the expected injury report forms (information is missing for one championship). The completeness of injury data provided by medical teams and local organising committee physicians averaged 95.8±6.5%. National medical teams reported 60.6±16.6% of all injuries, and local organising committee physicians 28.7±15.0% whereas 10.6±6.5% of injuries were reported by both.

CONCLUSIONS

The injury surveillance system used during international athletics championships provided good national medical team participation, coverage of athletes, response rate, and completeness of reports. These parameters should be systematically reported for injury surveillance studies to show the quality of the study.

Role of illness in male professional football: not a major contributor to time loss

BACKGROUND

There are limited data on the nature, type and incidence of illness in football. Previous studies indicate that gastrointestinal and respiratory tract illnesses are most common.

AIM

To describe the incidence and burden of illness in male professional football.

METHODS

Over the 4-year study period, 2011-2014, 73 professional football teams in Europe participated, with a total of 1 261 367 player-days recorded. All time-loss illnesses were recorded by the medical staff of each club. A recordable illness episode was any physical or psychological symptom (not related to injury) that resulted in the player being unable to participate fully in training or match play.

RESULTS

A total of 1914 illness episodes were recorded. The illness incidence was 1.5 per 1000 player-days, meaning that, on average, a player experienced an illness episode every second season, with a median of 3 days absence per illness episode. Severe illness (absence >4 weeks) constituted 2% of all illnesses. Respiratory tract illness was the most common (58%), followed by gastrointestinal illness (38%). Respiratory tract illness, gastrointestinal illness and cardiovascular illness caused the highest illness burden.

CONCLUSIONS

The illness incidence among male professional football players is low compared with the injury incidence. We found that the highest illness burden was caused by illness to the respiratory tract, gastrointestinal tract and cardiovascular system.

Clinical Practice Patterns and Beliefs in the Management of Hamstrings Strain Injuries

CONTEXT

Hamstrings strain injuries (HSIs) are among the most commonly occurring injuries in sport and are top causes of missed playing time. Lingering symptoms, prolonged recovery, and a high reinjury rate (12%-34%) make HSI management a frustrating and challenging process for the athletic trainer (AT). The clinical practice patterns and opinions of ATs regarding HSI treatment and rehabilitation are unknown.

OBJECTIVE

To examine the frequency of method use and opinions about current HSI management among ATs.

DESIGN

Cross-sectional study.

SETTING

Survey administered to registrants at the 2013 National Athletic Trainers' Association Clinical Symposia and AT Expo.

PATIENTS OR OTHER PARTICIPANTS

A total of 1356 certified ATs (691 men, 665 women; age = 35.4 ± 10.5 years, time certified = 11.92 ± 9.75 years).

DATA COLLECTION AND ANALYSIS

A survey was distributed electronically to 7272 registrants and on paper to another 700 attendees. Validity and reliability were established before distribution. Participants reported demographic information and rated their frequency of treatment and rehabilitation method use and agreement with questions assessing confidence, satisfaction, and desire for better clinical practice guidelines. Exploratory factor analysis and principal axis factor analysis were used. We also calculated descriptive statistics and χ(2) tests to assess practice patterns.

RESULTS

The response rate was 17% (n = 1356). A 2-factor solution was accepted for factor analysis (r = 0.76, r = 0.70), indicating that ATs follow either a contemporary or traditional management style. Various practice patterns were evident across employment settings and years of clinical experience. Satisfaction with the current HSI management plan was high (73.6%), whereas confidence in returning an athlete to play was lower (62.0%). Rates of use were associated with belief in effectiveness for all methods assessed (P < .001). Higher confidence levels were associated with high use of several methods; we observed increased satisfaction (χ(2)2 = 22.5, P = .002) but not increased confidence levels in more experienced ATs.

CONCLUSIONS

Our study demonstrated the lack of consensus in HSI treatment and rehabilitation and the ATs' desire for better clinical practice guidelines. Future research in which multimodal strategies, including both traditional and contemporary methods, are studied is warranted for effective management of HSI.

Association of y balance test reach asymmetry and injury in division I athletes

PURPOSE

The Y balance test (YBT) is a screen of dynamic balance requiring stance leg balance while the contralateral leg reaches in anterior (ANT), posteromedial (PM), and posterolateral (PL) directions. YBT has been proposed as a screen for injury risk; however, limited research has examined the association between YBT and injury. The purpose of this study was to examine the association between YBT (asymmetry and composite score (CS)) and noncontact injury in a sample of Division I (DI) college athletes from multiple sports.

METHODS

DI college athletes were screened with the YBT during the preparticipation examination to determine asymmetry (absolute difference between legs in ANT, PL, and PM) and CS (summed average of right/left ANT, PL, and PM normalized to leg length). Participants were followed throughout the sport season, and noncontact injuries requiring athletic training staff intervention were recorded for analysis. Demographic variables between injured and uninjured athletes were assessed with independent t-tests. Receiver operating characteristic (ROC) curves determined optimal cut points for predicting injury on the basis of CS and asymmetry. CS was analyzed as a continuous variable, as ROC curves were unable to maximize sensitivity and specificity. Logistic regression models adjusted for sport and previous injury determined the odds of injury on the basis of asymmetry and CS.

RESULTS

One hundred and eighty-four participants were included in analysis; 81 were injured. ROC curves determined asymmetry >4 cm (sensitivity, 59%; specificity, 72%) as the optimal cut point for predicting injury. Only ANT asymmetry was significantly associated with noncontact injury (odds ratio, 2.33; 95% confidence interval, 1.15-4.76).

CONCLUSIONS

ANT asymmetry >4 cm was associated with increased risk of noncontact injury. CS in this sample of DI athletes was not associated with increased risk of injury.

What are the Differences in Injury Proportions Between Different Populations of Runners? A Systematic Review and Meta-Analysis

BACKGROUND

Many runners suffer from injuries. No information on high-risk populations is available so far though.

OBJECTIVES

The aims of this study were to systematically review injury proportions in different populations of runners and to compare injury locations between these populations.

DATA SOURCES

An electronic search with no date restrictions was conducted up to February 2014 in the PubMed, Embase, SPORTDiscus and Web of Science databases. The search was limited to original articles written in English. The reference lists of the included articles were checked for potentially relevant studies.

STUDY ELIGIBILITY CRITERIA

Studies were eligible when the proportion of running injuries was reported and the participants belonged to one or more homogeneous populations of runners that were clearly described. Study selection was conducted by two independent reviewers, and disagreements were resolved in a consensus meeting.

STUDY APPRAISAL AND SYNTHESIS METHODS

Details of the study design, population of runners, sample size, injury definition, method of injury assessment, number of injuries and injury locations were extracted from the articles. The risk of bias was assessed with a scale consisting of eight items, which was specifically developed for studies focusing on musculoskeletal complaints.

RESULTS

A total of 86 articles were included in this review. Where possible, injury proportions were pooled for each identified population of runners, using a random-effects model. Injury proportions were affected by injury definitions and durations of follow-up. Large differences between populations existed. The number of medical-attention injuries during an event was small for most populations of runners, except for ultra-marathon runners, in which the pooled estimate was 65.6%. Time-loss injury proportions between different populations of runners ranged from 3.2% in cross-country runners to 84.9% in novice runners. Overall, the proportions were highest among short-distance track runners and ultra-marathon runners.

LIMITATIONS

The results were pooled by stratification of studies according to the population, injury definition and follow-up/recall period; however, heterogeneity was high.

CONCLUSIONS

Large differences in injury proportions between different populations of runners existed. Injury proportions were affected by the duration of follow-up. A U-shaped pattern between the running distance and the time-loss injury proportion seemed to exist. Future prospective studies of injury surveillance are highly recommended to take running exposure and censoring into account.

No association between fibrosis on magnetic resonance imaging at return to play and hamstring reinjury risk

BACKGROUND

Connective tissue scar (fibrosis) is a common finding on magnetic resonance imaging (MRI) after recovery from acute hamstring injuries. Fibrosis has been suggested as a predisposing factor for reinjury, but evidence from clinical studies is lacking.

PURPOSE/HYPOTHESIS

The aim of this study was to examine the association between the presence of fibrosis on MRI at return to play after an acute hamstring injury and the risk of reinjury. The hypothesis was that fibrous tissue on MRI was associated with an increased reinjury risk.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Magnetic resonance images were obtained from 108 consecutive athletes with modified Peetrons classification grade 1 or 2 hamstring injuries within 5 days of injury and within 7 days of return to play. The presence and extent of abnormally low signal intensity in the intramuscular tissue on MRI, suggestive of fibrosis, were assessed on both T1- and T2-weighted images. Reinjuries were recorded over a 1-year follow-up period. The association between fibrosis and reinjury risk was analyzed with a Cox proportional hazards model.

RESULTS

The MRIs of the initial injury showed 45 (43%) grade 1 and 63 (57%) grade 2 injuries. Median time of return to play was 30 days (interquartile range [IQR], 22-42 days). At return to play, 41 athletes (38%) had fibrosis on MRI with a median longitudinal length of 5.8 cm (IQR, 3.3-12.5 cm) and a median volume of 1.5 cm3 (IQR, 1.5-3.9 cm3). In athletes with fibrosis, 24% (10/41) sustained a reinjury, and in the subjects without fibrosis, 24% (16/67) had a reinjury, resulting in a hazard ratio of 0.95 (95% CI, 0.43-2.1; P=.898).

CONCLUSION

Fibrosis is commonly seen on MRI at return to play after grade 1 or 2 hamstring injuries but is not associated with reinjury risk.

Acute injuries in track and field athletes: a 3-year observational study at the Penn Relays Carnival with epidemiology and medical coverage implications

BACKGROUND

Few studies have examined acute injuries in track and field in both elite and subelite athletes.

PURPOSE

To observe the absolute number and relative rates of injury in track and field athletes across a wide range of competition levels and ages during 3 years of the Penn Relays Carnival to assist with future medical coverage planning and injury prevention strategies.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

Over a 3-year period, all injuries treated by the medical staff were recorded on a standardized injury report form. Absolute number of injuries and relative injury rates (number of injuries per 1000 competing athletes) were determined and odds ratios (ORs) of injury rates were calculated between sexes, competition levels, and events. Injuries were also broken down into major or minor medical or orthopaedic injuries.

RESULTS

Throughout the study period, 48,473 competing athletes participated in the Penn Relays Carnival, and 436 injuries were sustained. For medical coverage purposes, the relative rate of injury subtypes was greatest for minor orthopaedic injuries (5.71 injuries per 1000 participants), followed by minor medical injuries (3.42 injuries per 1000 participants), major medical injuries (0.69 injuries per 1000 participants), and major orthopaedic injuries (0.18 injuries per 1000 participants). College/elite athletes displayed the lowest relative injury rate (7.99 injuries per 1000 participants), which was significantly less than that of high school (9.87 injuries per 1000 participants) and masters athletes (16.33 injuries per 1000 participants). Male athletes displayed a greater likelihood of having a minor orthopaedic injury compared with female athletes (OR, 1.36 [95% CI, 1.06-1.75]; χ2 = 5.73; P = .017) but were less likely to sustain a major medical injury (OR, 0.33 [95% CI, 0.15-0.75]; χ2 = 7.75; P = .005). Of the 3 most heavily participated in events, the 4 × 400-m relay displayed the greatest relative injury rate (13.6 injuries per 1000 participants) compared with the 4 × 100-m and 4 × 200-m relays.

CONCLUSION

Medical coverage teams for future large-scale track and field events need to plan for at least 2 major orthopaedic and 7 major medical injuries per 10,000 participants. Male track and field athletes, particularly masters male athletes, are at greater risk of injury compared with other sexes and competition levels.

Sports injuries and illnesses in the Sochi 2014 Olympic Winter Games

BACKGROUND

Systematic surveillance of injuries and illnesses is the foundation for developing preventive measures in sport.

AIM

To analyse the injuries and illnesses that occurred during the XXII Olympic Winter Games, held in Sochi in 2014.

METHODS

We recorded the daily occurrence (or non-occurrence) of injuries and illnesses (1) through the reporting of all National Olympic Committee (NOC) medical teams and (2) in the polyclinic and medical venues by the Sochi 2014 medical staff.

RESULTS

NOC and Sochi 2014 medical staff reported 391 injuries and 249 illnesses among 2780 athletes from 88 NOCs, equalling incidences of 14 injuries and 8.9 illnesses per 100 athletes over an 18-day period of time. Altogether, 12% and 8% of the athletes incurred at least one injury or illness, respectively. The percentage of athletes injured was highest in aerial skiing, snowboard slopestyle, snowboard cross, slopestyle skiing, halfpipe skiing, moguls skiing, alpine skiing, and snowboard halfpipe. Thirty-nine per cent of the injuries were expected to prevent the athlete from participating in competition or training. Women suffered 50% more illnesses than men. The rate of illness was highest in skeleton, short track, curling, cross-country skiing, figure skating, bobsleigh and aerial skiing. A total of 159 illnesses (64%) affected the respiratory system, and the most common cause of illness was infection (n=145, 58%).

CONCLUSIONS

Overall, 12% of the athletes incurred at least one injury during the games, and 8% an illness, which is similar to prior Olympic Games. The incidence of injuries and illnesses varied substantially between sports.

Meta-narrative analysis of sports injury reporting practices based on the Injury Definitions Concept Framework (IDCF): A review of consensus statements and epidemiological studies in athletics (track and field)

OBJECTIVES

Consistency in routines for reporting injury has been a focus of development efforts in sports epidemiology for a long time. To gain an improved understanding of current reporting practices, we applied the Injury Definitions Concept Framework (IDCF) in a review of injury reporting in a subset of the field.

DESIGN

Meta-narrative review.

METHODS

An analysis of injury definitions reported in consensus statements for different sports and studies of injury epidemiology in athletics (track and field) published in PubMed between 1980 and 2013 was performed. Separate narratives for each of the three reporting contexts in the IDCF were constructed from the data.

RESULTS

Six consensus statements and 14 studies reporting on athletics injury epidemiology fulfilled the selection criteria. The narratives on sports performance, clinical examination, and athlete self-report contexts were evenly represented in the eligible studies. The sports performance and athlete self-report narratives covered both professional and community athletes as well as training and competition settings. In the clinical examination narrative, data collection by health service professionals was linked to studies of professional athletes at international championships.

CONCLUSIONS

From an application of the IDCF in a review of injury reporting in sports epidemiology we observed a parallel usage of reporting contexts in this field of research. The co-existence of reporting methodologies does not necessarily reflect a problematic situation, but only provided that firm precautions are taken when comparing studies performed in the different contexts.

Sports injury and illness epidemiology: Great Britain Olympic Team (TeamGB) surveillance during the Sochi 2014 Winter Olympic Games

Background

Sports injury and illness surveillance is the first step in injury and illness prevention, and is important for the protection of both athlete health and performance in major competitions.

Aim

To identify the prevalence, severity nature and causes of athlete injuries and illnesses in the Great Britain Olympic Team (TeamGB) during the Sochi 2014 Winter Olympic Games.

Methods

The observational prospective cohort study followed the Great Britain Injury/Illness Performance Project surveillance methodology and obtained information on injuries and illnesses that occurred during the Games between 30 January and 23 February 2014 in TeamGB athletes (n=56).

Results

Among the 56 TeamGB athletes, there were 27 injuries and 11 illnesses during the Olympic Games period. This equated to 39% sustaining at least one injury and 18% at least one illness, with an incidence of 48.2 injuries and 19.6 illnesses per 100 athletes, respectively. Of all injuries and illnesses, 9% and 7%, respectively, resulted in time loss. The risk of sustaining an injury was highest for freestyle skiing, skeleton and snowboarding; and lowest for curling, biathlon and Alpine skiing (with no reported injuries); with the lower limb being the most commonly injured location. Respiratory system illnesses were most frequently reported overall, and older female athletes were the ones most affected by illness.

Conclusions

The risk of injury was double the risk of illness for TeamGB athletes. Overall, the rate of time-loss issues was low. Methodological considerations are important when interpreting data, and prevention strategies should focus on those issues causing the greatest risk, in terms of prevalence and severity, to athlete health and performance.

Competing with injuries: injuries prior to and during the 15th FINA World Championships 2013 (aquatics)

BACKGROUND

Injury and illness surveillance is the foundation for the development of prevention strategies.

OBJECTIVE

To examine injuries among the aquatic disciplines in the 4 weeks prior to and during the 2013 FINA World Championships.

METHODS

The study was comprised of two components: (1) a retrospective athlete survey recording injuries in the 4 weeks prior to the Championships and (2) a prospective recording of injuries and illnesses by the medical teams of the participating countries and the local host medical team.

RESULTS

One-third of the 1116 responding athletes reported an injury/physical complaint in the 4 weeks prior to the Championships. Significantly more women (36.7%) than men (28.6%) reported injuries. Divers reported the highest rate of injury/physical complaints (55.7%). At the start of the Championships, 70% of injured respondents (n=258) were still symptomatic; however, full participation was expected by 76%. During the Championships, 186 new injuries were reported (8.3/100 registered athletes) with the highest injury incidence rate in water polo (15.3/100 registered athletes). The most common injured body part was the shoulder (21%). A total of 199 illnesses were reported during the Championships (9.0/100 registered athletes) with the most common diagnosis of illness being gastrointestinal infection. Environmental exposure (allergy, otitis and jellyfish stings) was responsible for 27% of all illnesses in open water swimming.

CONCLUSIONS

Injuries pose a significant health risk for elite aquatic athletes. A prospective study would improve understanding of out-of-competition injuries. Future injury and illness surveillance at FINA World Championships is required to direct and measure the impact of prevention strategies.

Hop performance and leg muscle power in athletes: Reliability of a test battery

OBJECTIVES

To measure the absolute and relative reliability and the smallest real difference (SRD) in three commonly used hop tests, two leg-power tests and the single-leg squat jump.

DESIGN

Methodological study.

SETTING

Clinical setting.

PARTICIPANTS

Fourteen healthy athletes (seven women and seven men) were evaluated in a standardized test-retest design.

MAIN OUTCOME MEASURES

The Intra-class correlation coefficient (ICC2.1), Standard Error of Measurement (SEM) and SRD were calculated for the vertical jump, one-leg hop for distance, side-hop, single-leg squat jump and knee-flexion and knee-extension power tests.

RESULTS

All tests showed good to excellent ICC (0.84-0.98). The SEM (%) ranged between 3.4 and 11.1 for the four hop tests and between 8.1 and 12.4 for the leg-power tests. The SRD (%) for the hop tests ranged between 9.3 and 30.7 and for the three power tests between 22.4 and 34.3.

CONCLUSIONS

The absolute reliability of this test protocol showed good to excellent ICC values and measurement errors of approximately 10%. This instrument can be recommended for determining function in terms of power in healthy athletes or late in the rehabilitation process. The tests' methodological errors must be considered and caution should be taken regarding the standardization procedure during testing.

Analyses of Helsinki 2012 European Athletics Championships injury and illness surveillance to discuss elite athletes risk factors

OBJECTIVE

To further analyze newly incurred injuries and illnesses (I&Is) during Athletics International Championships to discuss risk factors.

DESIGN

Prospective recording of newly occurred injuries and illnesses.

SETTING

The 2012 European Athletics (EA) Championships in Helsinki, Finland.

PARTICIPANTS

National team and local organizing committee physicians and physiotherapists and 1342 registered athletes.

MAIN OUTCOME MEASURES

Incidence and characteristics of new injuries and illnesses.

RESULTS

Ninety-three percent of athletes were covered by medical teams, with a response rate of 91%. One hundred thirty-three injuries were reported (incidence of 98.4 injuries per 1000 registered athletes). Sixty-two injuries (47%) resulted in time loss from sport. The most common diagnosis was hamstring strain (11.4% of injuries and 21% of time-loss injuries). Injury risk was higher in males and increased with age. The highest incidences of injuries were found in combined events and middle- and long-distance events. Twenty-seven illnesses were reported (4.0 illnesses per 1000 athlete days). The most common diagnoses were upper respiratory tract infection (33.3%) and gastroenteritis/diarrhea (25.9%).

CONCLUSIONS

During outdoor EA Championships, injury and illness incidences were slightly lower and injury characteristics were comparable with those during outdoor World Athletics Championships. During elite athletics Championships, gender (male), age (older than 30 years), finals, and some events (combined events and middle- and long-distance races) seem to be injury risk factors. Illness risk factors remain unclear. As in previous recommendations, preventive interventions should focus on overuse injuries, hamstring strains, and adequate rehabilitation of previous injuries, decreasing risk of infectious diseases transmission, appropriate event scheduling, sports clothes, and heat acclimatization.

Musculotendon variability influences tissue strains experienced by the biceps femoris long head muscle during high-speed running

The hamstring muscles frequently suffer injury during high-speed running, though the factors that make an individual more susceptible to injury remain poorly understood. The goals of this study were to measure the musculotendon dimensions of the biceps femoris long head (BFlh) muscle, the hamstring muscle injured most often, and to use computational models to assess the influence of variability in the BFlh's dimensions on internal tissue strains during high-speed running. High-resolution magnetic resonance (MR) images were acquired over the thigh in 12 collegiate athletes, and musculotendon dimensions were measured in the proximal free tendon/aponeurosis, muscle and distal free tendon/aponeurosis. Finite element meshes were generated based on the average, standard deviation and range of BFlh dimensions. Simulation boundary conditions were defined to match muscle activation and musculotendon length change in the BFlh during high-speed running. Muscle and connective tissue dimensions were found to vary between subjects, with a coefficient of variation (CV) of 17±6% across all dimensions. For all simulations peak local strain was highest along the proximal myotendinous junction, which is where injury typically occurs. Model variations showed that peak local tissue strain increased as the proximal aponeurosis width narrowed and the muscle width widened. The aponeurosis width and muscle width variation models showed that the relative dimensions of these structures influence internal muscle tissue strains. The results of this study indicate that a musculotendon unit's architecture influences its strain injury susceptibility during high-speed running.

Marginal zinc deficiency negatively affects recovery from muscle injury in mice

The aim of the present study was to elucidate whether the recovery from muscle injury is impaired in marginal zinc deficiency. C57BL/6 male mice were fed a marginally zinc-deficient diet (MZD: 8 mg Zn/kg diet), a zinc-adequate diet (ZA: zinc 35 mg Zn/kg diet), and a zinc-high diet (ZH: 190 mg Zn/kg diet) for 4 weeks. Muscle injury was induced in the gastrocnemius muscles using cardiotoxin. The gastrocnemius muscles of these mice were harvested at 3, 5, 7, 10, 14, and 20 days after injury. We evaluated the regeneration of the skeletal muscle with hematoxylin and eosin staining and developmental myosin heavy-chain (dMHC: implicated in regeneration) immunostaining. The rate of dMHC-positive cells was significantly low in MZD mice compared with ZA mice at 3 days after cardiotoxin injection. The peak dMHC expression was found at 3 days after injection in ZA mice, 5 days in ZH mice, and 7 days in MZD mice. These results suggest that recovery from muscle injury might be partly impaired and delayed in MZD mice. Therefore, we strongly suggest the appropriate zinc intake to prevent the impairment of skeletal muscle regeneration.

The Injury/Illness Performance Project (IIPP): A Novel Epidemiological Approach for Recording the Consequences of Sports Injuries and Illnesses

Background. Describing the frequency, severity, and causes of sports injuries and illnesses reliably is important for quantifying the risk to athletes and providing direction for prevention initiatives. Methods. Time-loss and/or medical-attention definitions have long been used in sports injury/illness epidemiology research, but the limitations to these definitions mean that some events are incorrectly classified or omitted completely, where athletes continue to train and compete at high levels but experience restrictions in their performance. Introducing a graded definition of performance-restriction may provide a solution to this issue. Results. Results from the Great Britain injury/illness performance project (IIPP) are presented using a performance-restriction adaptation of the accepted surveillance consensus methodologies. The IIPP involved 322 Olympic athletes (males: 172; female: 150) from 10 Great Britain Olympic sports between September 2009 and August 2012. Of all injuries (n = 565), 216 were classified as causing time-loss, 346 as causing performance-restriction, and 3 were unclassified. For athlete illnesses (n = 378), the majority (P < 0.01) resulted in time-loss (270) compared with performance-restriction (101) (7 unclassified). Conclusions. Successful implementation of prevention strategies relies on the correct characterisation of injury/illness risk factors. Including a performance-restriction classification could provide a deeper understanding of injuries/illnesses and better informed prevention initiatives.

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.