Sverker Nilsson

Injury and illness definitions and data collection procedures for use in epidemiological studies in Athletics (track and field): Consensus statement

Background Movement towards sport safety in Athletics through the introduction of preventive strategies requires consensus on definitions and methods for reporting epidemiological data in the various populations of athletes. Objective To define health-related incidents (injuries and illnesses) that should be recorded in epidemiological studies in Athletics, and the criteria for recording their nature, cause and severity, as well as standards for data collection and analysis procedures. Methods A 1-day meeting of 14 experts from eight countries representing a range of Athletics stakeholders and sport science researchers was facilitated. Definitions of injuries and illnesses, study design and data collection for epidemiological studies in Athletics were discussed during the meeting. Two members of the group produced a draft statement after this meeting, and distributed to the group members for their input. A revision was prepared, and the procedure was repeated to finalise the consensus statement. Results Definitions of injuries and illnesses and categories for recording of their nature, cause and severity were provided. Essential baseline information was listed. Guidelines on the recording of exposure data during competition and training and the calculation of prevalence and incidences were given. Finally, methodological guidance for consistent recording and reporting on injury and illness in athletics was described. Conclusions This consensus statement provides definitions and methodological guidance for epidemiological studies in Athletics. Consistent use of the definitions and methodological guidance would lead to more reliable and comparable evidence.

Injury patterns in Swedish elite athletics: annual incidence, injury types and risk factors

Objective To estimate the incidence, type and severity of musculoskeletal injuries in youth and adult elite athletics athletes and to explore risk factors for sustaining injuries. Design Prospective cohort study conducted during a 52-week period. Setting Male and female youth and adult athletics athletes ranked in the top 10 in Sweden (n=292). Results 199 (68%) athletes reported an injury during the study season. Ninety-six per cent of the reported injuries were non-traumatic (associated with overuse). Most injuries (51%) were severe, causing a period of absence from normal training exceeding 3 weeks. Log-rank tests revealed risk differences with regard to athlete category (p=0.046), recent previous injury (>3 weeks time-loss; p=0.039) and training load rank index (TLRI; p=0.019). Cox proportional hazards regression analyses showed that athletes in the third (HR 1.79; 95% CI 1.54 to 2.78) and fourth TLRI quartiles (HR 1.79; 95% CI 1.16 to 2.74) had almost a twofold increased risk of injury compared with their peers in the first quartile and interaction effects between athlete category and previous injury; youth male athletes with a previous serious injury had more than a fourfold increased risk of injury (HR=4.39; 95% CI 2.20 to 8.77) compared with youth females with no previous injury. Conclusions The injury incidence among both youth and adult elite athletics athletes is high. A training load index combing hours and intensity and a history of severe injury the previous year were predictors for injury. Further studies on measures to quantify training content and protocols for safe return to athletics are warranted.

Prevalence of Musculoskeletal Injuries in Swedish Elite Track and Field Athletes

Background: Little is known of injury patterns in track and field (athletics). Injury prevalence has been proposed as the most appropriate measure of the injury rate in sports where athletes are at risk for overuse problems. Purpose: To ascertain 1-year retrospective and current prevalence of injury in elite track and field athletes to help plan injury prevention programs for this sport. Study Design: Descriptive epidemiology study. Methods: Two hundred seventy-eight youth (16 years old) and adult athletes from an eligible study population of 321 athletes were included. Results: The 1-year retrospective injury prevalence was 42.8% (95% confidence interval [CI], 36.9%-49.0%); the point prevalence was 35.4% (95% CI, 29.7%-41.4%). The diagnosis group displaying the highest injury prevalence was inflammation and pain in the gradual onset category (1-year prevalence, 20.9%; 95% CI, 16.2%-26.2%; and point prevalence, 23.2%; 95% CI, 18.4%-28.7%). A strong tendency for higher 1-year prevalence of 16.5% (95% CI, 12.2%-21.4%) than point prevalence of 8.5% (95% CI, 5.5%-12.5%) was recorded for sudden onset injuries in the diagnosis group sprain, strain, and rupture. The body region showing the highest injury prevalence was the knee and lower leg with 15.0% (95% CI, 11.0%-19.8%) 1-year prevalence and 13.7% (95% CI, 9.8%-18.3%) point prevalence, followed by the Achilles tendon, ankle, and foot/toe with 11.7% (95% CI, 8.2%-16.1%) 1-year prevalence and 11.4% (95% CI, 7.9%-15.8%) point prevalence. Conclusion: The injury prevalence is high among Swedish elite track and field athletes. Most of the injuries affect the lower extremities and are associated with a gradual onset. Although it is associated with a potential recall bias, the 1-year retrospective prevalence measure captured more sudden onset injuries than the point prevalence measure. Future prospective studies in track and field are needed to identify groups of athletes at increased risk.

Design of a protocol for large-scale epidemiological studies in individual sports: the Swedish Athletics injury study

Background Epidemiological studies have mainly been performed on team sports. The authors set out to develop a protocol for large-scale epidemiological studies of injuries among elite athletics athletes. Methods An argument-based method for investigation of complex design problems was used to structure the collection and analysis of data. Specification of the protocol was preceded by an examination of requirements on injury surveillance in individual sports and iterated drafting of protocol specifications, and followed by formative evaluations. Results The requirements analysis shows that the central demand on the protocol is to allow for detailed epidemiological analyses of overuse injuries, which subsequently requires regular collection of self-reported data from athletes. The resulting study protocol is centred on a web-based weekly athlete e-diary enabling continual collection of individual-level data on exposure and injuries. To be able to interpret the self-reported data on injury events, collection of a wide range of personal baseline data from the athlete, including a psychological profile, is included in the protocol. Conclusions The resulting protocol can be employed in intervention programmes that can prevent suffering among both adult elite and youth talent athletes who have made considerable life investments in their sport.

The psychological factor ‘self-blame’ predicts overuse injury among top-level Swedish track and field athletes: a 12-month cohort study

Background Athletes’ psychological characteristics are important for understanding sports injury mechanisms. We examined the relevance of psychological factors in an integrated model of overuse injury risk in athletics/track and field. Methods Swedish track and field athletes (n=278) entering a 12-month injury surveillance in March 2009 were also invited to complete a psychological survey. Simple Cox proportional hazards models were compiled for single explanatory variables. We also tested multiple models for 3 explanatory variable groupings: an epidemiological model without psychological variables, a psychological model excluding epidemiological variables and an integrated (combined) model. Results The integrated multiple model included the maladaptive coping behaviour self-blame (p=0.007; HR 1.32; 95% CI 1.08 to 1.61), and an interaction between athlete category and injury history (p<0.001). Youth female (p=0.034; HR 0.51; 95% CI 0.27 to 0.95) and youth male (p=0.047; HR 0.49; 95% CI 0.24 to 0.99) athletes with no severe injury the previous year were at half the risk of sustaining a new injury compared with the reference group. A training load index entered the epidemiological multiple model, but not the integrated model. Conclusions The coping behaviour self-blame replaced training load in an integrated explanatory model of overuse injury risk in athletes. What seemed to be more strongly related to the likelihood of overuse injury was not the athletics load per se, but, rather, the load applied in situations when the athletes body was in need of rest.

Electronic data capture on athletes' pre-participation health and in-competition injury and illness at major sports championships: an extended usability study in athletics

This study set out to identify factors critical for the usability of electronic data collection in association with championships in individual sports. A qualitative analysis of electronic data collection system usability for collection of data on pre-participation health from athletes and in-competition injury and illness from team physicians was performed during the 2013 European Athletics Indoor Championships. A total of 15 athletes and team physicians participated. Athletes were found to experience few problems interacting with the electronic data collection system, but reported concerns about having to reflect on injury and illness before competitions and the medical terminology used. Team physicians encountered problems when first navigating through the module for clinical reporting, but they were not subjected to motivational problems. We conclude that athletes’ motivation to self-report health data and the design of the human–computer interface for team physicians are key issues for the usability of electronic data collection systems in association with championships in individual sports.

SUBSEQUENT INJURY DURING INJURY RECOVERY IN ELITE ATHLETICS: COHORT STUDY IN SWEDISH MALE AND FEMALE ATHLETES

Background In elite athletics, epidemiological studies covering cross-discipline populations of athletes have reported a heavy burden of injuries related to overuse. Many athletes continue to expose themselves to extensive training and competition loads while suffering from partial time loss injuries (forcing them to change their practice schedules). Objective To examine risk indicators associated with sustaining a secondary (subsequent) injury while recovering from a primary (index) injury. Design Prospective epidemiological study using web-based data collection. Setting Swedish elite youth (U17) and adult athletics athletes. Data were collected between March 2009 and March 2010. Participants 292 youth and adult athletes (91%) responded regularly to web-based questionnaires from an eligible study population of 321 athletes. Risk factor assessment Athletes sex, age, event group and training load. Main outcome measures Secondary new injury during recovery from a primary (index) injury. Results A total of 122 (42 %) of the athletes reported more than one injury during the study period. Multiple Cox proportional hazards regression analyses revealed risk differences with regard to event group (P=.006) and training load (P=.047) for athletes who sustained a secondary new injury during recovery from a first injury; athletes in the combined events group (hazard ratio (HR) 4.14; 95% CI 1.82–9.40) had almost a fourfold increased risk compared to jumpers and throwers and athletes in the third TLRI quartile (HR=2.02; 95% CI 1.29–3.63) a twofold risk for sustaining a secondary injury compared with their peers. Conclusions The risk for sustaining a new secondary injury while recovering from a primary injury is high among athletics athletes. Competing in combined events and a high score in the training load index (combining hours and intensity) are associated with particularly increased risk. Further studies measuring training content during the rehabilitation period and development of protocols for safe return to athletics are warranted.

The Swedish athletics study: design of a protocol for large-scale epidemiological studies in individual sports

Background Epidemiological studies of injury have mainly been performed on team sports. Present methods for data collection and analysis neglect important features of individual sports. Aims To develop a study protocol for large-scale epidemiological studies of injuries in individual sports, exemplified by athletics. Design Structured information system development. Specification of the study protocol was preceded by an examination of requirements on injury surveillance in individual sports and iterated drafting of protocol specifications, and followed by formative evaluations. A preliminary protocol was evaluated in a pilot study involving athletic coaches and athletes and revised into the final version. Setting Swedish youth and adult elite athletics. Participants Six elite athletics coaches and 22 athletic athletes. Results The requirements analysis showed that the central demand on a study protocol to be used for epidemiological surveillance in athletics is to enable detailed analyses of overuse injuries, which subsequently requires continuous and prospective collection of athlete self-reported data. The study protocol fulfils these requirements by using a web-based athlete diary for collection of data regarding exposure to practice and competition as well as injuries. In addition, the requirements analysis showed that the study protocol should cover collection of detailed baseline data, including injury history, subject characteristics and a psychological profile. The evaluation data showed that the preliminary protocol only needed minor revisions at the level of web-questionnaire design. Conclusion The resulting study protocol for injury surveillance is specifically targeted at individual sports. It can be employed in surveillance preceding intervention programs for preventing injuries and suffering among both adult elite and youth athletes. Electronic data capture is crucial for injury surveillance in individual sports, such as athletics in order to ensure high validity of data.

The swedish athletics study: various prevalence measures of musculoskeletal injury in élite athletics athletes

Background Athletics is one of the most popular global sports, but little is known of injury patterns among élite athletic athletes. Injury prevalence has been proposed to be the most valid measure of injury burden in sports where athletes practice long hours and are at risk for overuse problems. Objective To compare two different indicators of injury prevalence in athletics as measures of the injury burden among adult and youth élite athletics athletes. Design Cross-sectional epidemiological study using web-based data collection. Setting Swedish élite youth (U17) and adult athletics athletes. Data were collected in April 2009. Participants 278 youth and adult athletes (91%) submitted a web-based questionnaire from an eligible study population of 301 athletes. Assessment of risk factors Athletes sex, age and anatomical body regions were assessed as risk factors. Main outcome measures 1-year prevalence of musculoskeletal injuries causing at least 3 weeks of partial or complete absence from practice and competition; point prevalence of musculoskeletal injury. Results The 1-year injury prevalence was 43.6%. Among the age groups, the prevalence was 48.1% for adult and 37.1% for youth athletes. The point prevalence of injury was 36.2%, 38% among adult athletes and 33% among youth athletes. Female youth athletes had a tendency towards higher 1-year (p=0.06) and point (p=0.025) injury prevalence than male youth athletes. There was no sex difference in injury prevalence among the senior athletes. A majority of the injuries (74% 1-year prevalence; 78% point prevalence) reported by the athletes were located to the lower extremities. Conclusion Using either the point or 1-year retrospective window definition of prevalence, currently approximately 4 out of 10 Swedish élite athletic athletes have injuries that interfere with their performance of sports activities. Most injuries are located to the lower extremities. Prospective epidemiological studies investigating individual risk factors for athletic injuries are warranted.

PRE-PARTICIPATION HEALTH QUESTIONNAIRE IN MAJOR ATHLETIC CHAMPIONSHIPS: FEASIBILITY AND INTEREST TO DETERMINE INJURY AND ILLNESS RISK FACTORS

Background The current injury and illness (I&I) surveillance system in association to athletics championships have to be improved by collecting pre-participation data for risk factors analyses. Objectives To evaluate a pre-participation health questionnaire (PHQ) for collecting health status data from athletes for risk factors analyses and to describe incidence and characteristics of I&I occurred during a major indoor Athletics championships. Design Cohort study using retrospective athlete self-report data on health status for the 4 weeks prior to the championship and prospective recording of in-championship injuries and illnesses. Setting 32st European Athletics Indoor Championships 2013 in Göteborg, Sweden. Participants A sub-cohort of athletes (n=127) for PHQ study and 577 registered athletes for I&I study. Risk factor assessment Age, gender, pre-competition pain, pre-competition injury, pre-competition illness, pre-competition training load and fatigue. Main outcome measures Newly incurred injury and illness at the championships. Results In the I&I study, 60 injuries (104.6/1000 registered athletes) were recorded. The most common injury cause was “field play conditions” (31%), followed by overuse (29%). 29 illnesses were reported (12.6 illnesses per 1000 athlete days), with upper respiratory tract infection and gastro-enteritis/diarrhoea as the most common diagnoses. 74 athletes submitted a complete PHQ (58.3%). An univariate statistical analysis showed that athletes having trained more than 12 hours per week were at increased risk for suffering a new injury (Relative risk (RR)=4.9 (95% Confidence interval (95% CI):1.2–20.7)), and athletes who presented a pre-participation health problem were more likely to suffer a new illness (RR=2.7; (95% CI:1.1–6.7)). Conclusions An athlete self-report PHQ was feasible and allowed for pre-participation screening of individuals at risk. Injury risk during indoor championships seems slightly lower than during outdoor championships with specific injury types that can be attributed to the indoor track conditions.