Why we should focus on the burden of injuries and illnesses, not just their incidence

Incidence, Prevalence, and Burden of Health Problems in Elite Female Ice Hockey Players-A One-Season Prospective Study

Introduction: Epidemiological studies on elite female ice hockey players are lacking but needed to tailor preventive efforts in this growing group of athletes. Therefore, the aim of this study was to describe the incidence, prevalence, and burden of health problems in elite female ice hockey players. Methods: In this prospective cohort study, we asked all Swedish Women's Hockey League (SWHL) players (N = 207) to report their health status on the OSTRC-H2 weekly throughout the 2022/2023 season (28 weeks). Reported problems were categorized as injuries (acute or overuse) or illnesses and presented as incidence per player season and mean weekly prevalence. Results: A total of 129 players (62% of all SWHL players) provided 2286 health reports with a mean weekly response rate of 67%. Mean weekly prevalence of health problems was 21% (95% confidence interval [CI]: 19-23) (injuries: 15% [95% CI: 14-17] and illnesses: 6% [95% CI: 5-8]). Injury incidence was 2.1 (95% CI: 1.8-2.4) per player season (acute: 1.2 [95% CI: 1.0-1.5] and overuse: 0.8 [95% CI: 0.7-1.1]). Illness incidence was 1.3 per player season (95% CI: 1.1-1.6). Most reported health problems were acute injuries (59.4% of reported injuries). Most common among acute injuries where to the shoulder (15%), head (13%), and knee (11%). The hip/groin was the most reported (35%) and burdensome (49% of severity score) region among overuse injuries. Reported illnesses were mostly represented by respiratory infections (75%). Conclusions: In average, one in five elite ice hockey players reported a health problem at any given time during the season. Results of this study highlight the need to develop and test primary prevention strategies for shoulder, head, and knee injuries and secondary prevention strategies for hip and groin problems.

Injury-inciting circumstances of sudden-onset hamstring injuries: video analyses of 63 match injuries in male professional football players in the Qatar Stars League (2013-2020)

OBJECTIVE

To describe and categorise the injury-inciting circumstances of sudden-onset hamstring match injuries in professional football players using systematic video analysis.

METHODS

Using a prospective injury surveillance database, all sudden-onset hamstring match injuries in male football players (18 years and older) from the Qatar Stars League between September 2013 and August 2020 were reviewed and cross-referenced with broadcasted match footage. Videos with a clear observable painful event (ie, a player grabbing their posterior thigh) were included. Nine investigators independently analysed all videos to describe and categorise injury-inciting circumstances. We used three main categories: playing situation (eg, time of injury), player action(s) (eg, running) and other considerations (eg, contact). Player action(s) and other considerations were not mutually exclusive.

RESULTS

We included 63 sudden-onset hamstring match injuries out of 295 registered injuries between 2013 and 2020. Running was involved in 86% of injuries. Hamstring injuries occurred primarily during acceleration of 0-10 m (24% of all injuries) and in general at different running distances (0-50 m) and speeds (slow to fast). At 0-10 m distance, indirect player-to-player contact and inadequate balance were involved in 53% and 67% of the cases, respectively. Pressing occurred in 46% of all injuries (injured player pressing opponent: 25%; being pressed by opponent: 21%) and frequently involved player-to-player contact (69% of the cases when the injured player was pressing vs 15% of the cases when the opponent was pressing) and inadequate balance (82% vs 50%, respectively). Other player actions that did not involve running (n=9, 14% of all injuries) were kicking (n=6) and jumping (n=3).

CONCLUSION

The injury-inciting circumstances of sudden-onset hamstring match injuries in football varied. The most common single-player action (24%) was acceleration over a distance of <10 m. Pressing, inadequate balance and indirect contact were frequently seen player actions. Injury prevention research in football should look beyond high-speed running as the leading risk factor for sudden-onset hamstring injuries.

The validity and reliability of a Japanese version of the web-based hamstring outcome score

This study aimed to translate a web-based hamstring outcome score (HaOS) questionnaire to the Japanese context. First, the validity and reliability of the translated questionnaires were examined among Japanese athletes. Second, the association between the previous history of hamstring strain and HaOS was examined. The translation was performed according to internationally recognized methodologies. A total of 233 athletes were asked to complete the HaOS questionnaire, and four questions were added to examine the content validity of the questionnaire. Intraclass correlation coefficient (ICC) was calculated to evaluate the test-retest reliability. Internal consistency was determined by calculating Cronbach's alpha values. The translated questionnaires had high acceptance and compliance rates, with a response rate of 84.4%. The ICC for each scale ranged from 0.80 to 0.93, and Cronbach's α from 0.72 to 0.96, confirming good reliability and high internal consistency. HaOS of the previous injury group (93.4 [78.9, 100]) was significantly lower than that of the healthy group (86.2 [68.1, 100]) (p < 0.05). The translated HaOS questionnaires were valid, reliable, and acceptable for monitoring hamstring conditions in Japanese athletes.

Injury Risk in Elite Young Male Soccer Players: A Review on the Impact of Growth, Maturation, and Workload

ABSTRACT

Ribeiro, N, Martinho, DV, Pereira, JR, Rebelo, A, Monasterio, X, Gonzalo-Skok, O, Valente-dos-Santos, J, and Tavares, F. Injury risk in elite young male soccer players: a review on the impact of growth, maturation, and workload. J Strength Cond Res 38(10): 1834-1848, 2024-The long-term development of young male soccer players involves a prolonged period of significant adjustments, highlighting the importance of studying the complex interaction between dynamic variables, including workload, and inherent elements like growth and maturity. This analysis examines the intricate connections involving the development, maturity, workload, and susceptibility to injuries among adolescent male soccer players. Significantly, these connections become prominent at the peak height velocity (PHV) period, a crucial moment in maturation. Growth rates vary among individuals, and higher rates have been associated with an increased risk of injury in young soccer players, particularly during periods of rapid growth. Identifying possible risk factors and understanding the complex connections between them is crucial to developing specific methods for reducing the risk of injury. Sharing this valuable information with essential stakeholders is crucial for guaranteeing young athletes' comprehensive growth and maturation process. Furthermore, this review emphasizes the immediate need for long-term studies and thorough injury analyses to comprehend better the dynamic interactions that influence injury patterns in young male soccer players. This review will allow practitioners to better understand the main modifiable and nonmodifiable risk factors for injury and provide essential information focusing on practical strategies, facilitating more informed decision making by all stakeholders. The review aims to clarify these complexities and offer crucial insights that can assist in designing and implementing efficient strategies to reduce the risk of injury, specifically for the challenges faced during PHV and within the broader framework of long-term athletic development in young soccer.

An injury burden heat map of all men's and women's teams of a professional football club over a decade

The aim was to present a descriptive 10-season summary of injury data from all teams of a professional football club using a heat map approach. Injuries and exposure time were registered according to the FIFA consensus in all men's and women's teams from Athletic Club over 10 seasons. A team-by-injury table was created, showing the incidence, median severity, and burden in each cell. Cells were coloured based on the injury burden value using a green - yellow-red gradient (lowest to highest). The highest overall injury burden was found in the women's 2nd and 1st teams and the men's U(under)17 team (>200 days lost/1000 h). Muscle injury burden demonstrated an increasing pattern with age. Knee joint/ligament injuries, particularly anterior cruciate ligament ruptures, had the highest impact on women's teams, followed by the men's 2nd team. In comparison, ankle joint/ligament injuries had a relatively low injury burden in most teams. Growth-related injuries were the most impactful injuries in the men's U15 and younger teams, and the women's U14 team. In conclusion, epidemiological data on injuries can inform and guide injury management processes. New and improved visualization methods might be important assets when presenting injury data to key decision-makers.

Imaging and Surgical Procedures After Surface-Related Collegiate Football Injuries on Artificial Turf Versus Natural Grass: Prevalence and Trends Over 15 Seasons

Background

Few longitudinal studies exist comparing medical procedures after football injuries on artificial and natural grass surfaces.

Purpose/Hypothesis

The purpose of this study was to specifically compare imaging and surgical procedures after surface-related collegiate football injuries on artificial turf versus natural grass. It was hypothesized that there would be no difference in the incidence of imaging and surgical procedures, combined medical procedures, or combined substantial and severe injuries over time between these surfaces.

Study Design

Cohort study; Level of evidence, 2.

Methods

A total of 39 universities across all Football Bowl Subdivision conferences were evaluated over 15 seasons (2006-2020). Playing surfaces evaluated were either a heavyweight artificial turf infill system (≥9.0 lb infill/ft2) or natural grass. Outcomes of interest included medical procedures across injury category, primary injury type, injury location, and specific procedures. Data involved multivariate analyses of variance (MANOVA) and Wilks λ criteria using general linear model procedures and were expressed as medical procedure incidence rates (IRs) per 10-game season.

Results

Overall, 2224 games were documented: 1106 (49.7%) on artificial turf and 1118 (50.3%) on natural grass. Of the 9137 total injuries reported, 4010 (44%) were surface-related cases. MANOVA indicated significant main effects between surfaces according to imaging procedure (F 2,1738 = 4.718; P = .009), surgical procedure (F 1,539 = 5.974; P = .003), and medical diagnosis (F 2,456 = 2.643; P = .040). Post hoc analyses indicated significantly lower (P < .05) incidences on artificial turf versus natural grass, respectively, for the following outcomes: imaging procedures ordered after player-to-surface impact trauma (IR [95% CI], 1.5 [1.3-1.8] vs 2.1 [1.9-2.4]), shoe-to-surface trauma during physical contact (4.4 [4.1-4.7] vs 5.2 [4.9-5.5]), foot injuries (0.6 [0.5-0.7] vs 1.1 [0.9-1.2]), ligament sprains/tears (4.6 [4.3-4.9] vs 5.3 [5.0-5.6]), muscle strains/tears (0.2 [0.2-0.3] vs 0.7 [0.6-0.9]), surgeries performed after shoe-to-surface trauma during physical contact (1.1 [0.9-1.3] vs 1.6 [1.4-1.8]), lower body surgeries (1.8 [1.6-2.0] vs 2.3 [2.1-2.6]), and surgeries involving ligament tears (1.0 [0.9-1.2] vs 1.5 [1.3-1.7]), as well as fewer diagnoses of syndesmosis sprains/tears (0.7 [0.5-0.8] vs 1.0 [0.8-1.2]) and Lisfranc trauma (0.3 [0.2-0.4] vs 0.5 [0.4-0.7]). Trends over the 15 seasons indicated a significant rise in combined medical procedures (P = .005) and combined substantial and severe injuries (P = .0007) irrespective of surface.

Conclusion

Results indicated that collegiate football competition on heavyweight artificial turf resulted in lower incidences of imaging and surgical procedures and medical diagnoses compared with natural grass.

The netball injury evidence base: a scoping review of methodologies and recommendations for future approaches

BACKGROUND

Netball is a sport with a large participation base and a high risk of injuries. Effective injury prevention strategies are dependent upon a clear understanding of injury issues, aetiology and mechanisms, requiring robust research methodologies to ensure a reliable evidence base. This scoping review aims to identify the characteristics and range of netball injury research methodologies, to inform recommendations for future research.

METHODS

A systematic search of SPORTDiscus, MEDLINE, CINAHL and Academic Search Complete, PubMed, Scopus and Web of Science, from 1985 to May 2023 identified relevant studies. Inclusion criteria included peer-reviewed studies assessing injury incidence, aetiology and mechanisms in netball.

RESULTS

Following screening, 65 studies were included (68% descriptive epidemiology, 32% analytic epidemiology). Descriptive epidemiology reported data from hospital/clinic and insurance databases (57%) and netball competitions (43%). Only two studies used ongoing, systematic injury surveillance in netball cohorts, and significant heterogeneity existed in study designs, data collection methods, injury definitions and injury incidence rates calculations. Studies assessed a limited number of risk factors (descriptive competition studies: median: n = 4; analytic studies median: n = 6), with 76% using a simplistic reductionist approach to determine causality. Basic descriptions and retrospective recall of injury mechanisms reduced accuracy. Only two studies conducted comprehensive assessments of injury mechanisms using video-based methods.

CONCLUSION

To establish an accurate netball injury evidence base, future research should prioritise the development of reliable, continuous surveillance systems. The International Olympic Committee (IOC) consensus statement guidelines are recommended for accurate injury data collection and reporting. A multifactorial approach should be adopted to assess the complex interaction between multiple risk factors, player load and the injury inciting event. Comprehensive descriptions of injury mechanisms using video methods, alongside descriptions from medical staff are recommended. This information is crucial for developing targeted prevention strategies.

An Investigation Into the Measurement of Injury Severity in Running-Related Injury Research: A Scoping Review

Understanding injury severity is essential to inform injury prevention practice. The aims of this scoping review were to investigate how running-related injury (RRI) severity is measured, compare how it differs across studies, and examine whether it influences study outcomes (i.e., injury rates and risk factor identification). This scoping review was prospectively registered with Open Science Framework. A systematic electronic search was conducted using PubMed, Scopus, SPORTDiscuss, MEDLINE, and Web of Science databases. Included studies were published in English between January 1980 and December 2023, investigated RRIs in adult running populations, and included a measure of injury severity. Results were extracted and collated. Sixty-six studies were included. Two predominant primary criteria are used to define injury severity: the extent of the effect on running and/or the extent of the physical description. When secondary definition criteria are considered, 13 variations of injury severity measurement are used. Two approaches are used to grade injury severity: a categorization approach or a continuous numerical scale. Overall, the measurement of RRI severity is relatively inconsistent across studies. Less than half of studies report incidence rates per level of injury severity, while none report specific risk factors across levels, making it difficult to determine if the approach to measuring injury severity influences these study outcomes. This lack of information is possibly contributing to inconsistent rates of RRIs reported, and the lack of clarity on risk factors.

A prospective study of injuries and illnesses among 910 amateur golfers during one season

ABSTRACT

Objectives

Our aims were (a) to describe the prevalence and incidence of self-reported injuries and illnesses of amateur golfers over a 5-month period and (b) to investigate potential risk factors for injury.

Methods

We recruited 910 amateur golfers (733 males [81%] and 177 females [19%]) from golf clubs in the USA and Switzerland. The median age was 60 (IQR: 47-67) and the median golfing handicap was 12 (IQR: 6-18). Participants' health was monitored weekly for 5 months using the Oslo Sports Trauma Research Centre Questionnaire on Health Problems. Players also completed a baseline questionnaire on personal and golf-specific characteristics and their medical history.

Results

We distributed 19 406 questionnaires and received 11 180 responses (57.6%). The prevalence of injuries was 11.3% (95% CI: 9.8 to 12.8) and of illnesses was 2% (95% CI 1.7 to 2.2). The incidence of injuries and illnesses was 3.79 (95% CI 3.54 to 4.06) and 0.94 (95% CI 0.81 to 1.07) per golfer per year, respectively. The injury regions with the highest burden of injury (time-loss days per player per year) were lumbosacral spine (5.93), shoulder (3.47) and knee (2.08). Injury risk was higher with increased age, osteoarthritis and previous injury.

Conclusion

The prevalence and incidence of injury and illness in amateur golf were low compared with many other sports. To further reduce the burden of injury, future research attention should be directed towards the lumbosacral spine, knee and shoulder.

Injury and illness surveillance monitoring in team sports: a framework for all

BACKGROUND

Sport-related injuries and illnesses can negatively impact athlete welfare at all standards of participation in team sports. Injury and illness surveillance (IIS), and the development of monitoring systems, initiates the sequence of injury and illness prevention. Operational IIS monitoring systems help to appraise epidemiological estimates of injury and illness incidence and burden in various athlete populations. However, the methodological underpinnings of various monitoring systems are not harmonized or widely documented, with the presence of efficient and successful programmes rarely showcased at non-elite levels. The aim is to provide a framework that guides the development of IIS, which will enhance overall surveillance, to indirectly inform injury prevention strategies.

METHODS

The process involved all members of the research group initially discussing the research gaps, scope of the project, and the aims of the article. Unique experiences were shared, and specific and global challenges and barriers to IIS at all standards of team sport participation were identified. A tiered system of data collection with corresponding content were produced, with experiences and guidance provided throughout the article.

RESULTS

The literature has been reviewed and using first-hand experience in conducting IIS programmes in complex and diverse sport settings, the authors have identified key enablers and barriers for best practise as time, technological and human resources, reporter/practitioner training, and medical expertise. Areas of greatest importance regarding the conducting of IIS have been outlined, providing guidance and recommendations across all levels of team sport participation. These areas include definitions, data context, collection procedures, handling, security, ethics, storage, dissemination, quality, compliance, and analysis. Given the barriers to IIS, 3-tiered levels of data collection and content have been proposed. The levels indicate data collection variables, with a focus on sufficiency and achievability, aiming to support the successful conducting of IIS in team sports across all standards of participation. Future opportunities in IIS have been discussed, with several predictive measures and analytical techniques expanded upon.

CONCLUSIONS

The framework provides universal guidance for implementing IIS monitoring systems, facilitating athletes, coaches, parents/guardians, governing bodies and practitioners to implement IIS processes, identify challenges, complete analysis, and interpret outcomes at all standards of participation.

Injury Profile in Youth Female Athletes: A Systematic Review and Meta-Analysis

BACKGROUND

An increasing number of epidemiological studies assessing the incidence, prevalence and severity of injury in youth female sport are available. However, no study has sought to synthesise the current evidence base across all youth female sport. As such, a systematic review and meta-analysis of injury in this cohort is necessary to understand the diversity of injury and its associated burden between sports in addition to identifying the density of research available.

OBJECTIVE

To conduct a systematic review and meta-analysis of epidemiological data of injuries in youth female athletes with particular attention to injury incidence, mean days lost and injury burden.

METHODS

Searches were performed in PubMed, EBSCO (SPORTDiscus with Full Text MEDLINE, APA PsycINFO, CINAHL, Academic Search Complete) and Cochrane databases. Studies were considered if they reported time-loss injury incidence or prevalence in youth female (≤ 19 years old) athletes. Study quality and risk of bias were assessed using STROBE-SIIS extension, Newcastle-Ottawa Scale, and funnel plots, respectively. Injury incidence and burden rate data were modelled using a mixed-effect Poisson regression model. Days lost data were modelled using a generalised linear mixed model.

RESULTS

Thirty-two studies were included. The overall incidence rate, mean days lost per injury, and burden rate were 4.4 injuries per 1000 h (95% CI 3.3-5.9), 10 days (95% CI 6-15), and 46 days per 1000 h (95% CI 23-92), respectively. Forty percent of athletes sustained at least one time-loss injury. Competitive level was a significant moderator of match and training injury incidence, with elite youth athletes presenting greater pooled injury incidence estimates than non-elite athletes (p = 0.0315 and p = 0.0047, respectively). The influence of moderators on days lost and injury burden could not be determined due to an insufficient number of studies for analysis.

CONCLUSION

Despite a broad inclusion criterion, there is limited injury surveillance research available across youth female sport. Outside of soccer, little research density is evidenced with single studies available in popular team sports such as Australian football and rugby union. Insufficient study numbers reporting mean days lost and injury burden data were available for analysis, and pooled days lost data could only be estimated for soccer. This highlights a need for future research to report days lost data alongside injury number and exposure so burden can be calculated and the full risk of injury to youth female athletes can be identified.

Hamstring muscle injuries in athletics

Hamstring muscle injuries (HMI) are a common and recurrent issue in the sport of athletics, particularly in sprinting and jumping disciplines. This review summarizes the latest literature on hamstring muscle injuries in athletics from a clinical perspective. The considerable heterogeneity in injury definitions and reporting methodologies among studies still needs to be addressed for greater clarity. Expert teams have recently developed evidence-based muscle injury classification systems whose application could guide clinical decision-making; however, no system has been adopted universally in clinical practice, yet.The most common risk factor for HMI is a previously sustained injury, particularly early after return-to-sport. Other modifiable (e.g. weakness of thigh muscles, high-speed running exposure) and non-modifiable (e.g. older age) risk factors have limited evidence linking them to injury. Reducing injury may be achieved through exercise-based programs, but their specific components and their practical applicability remain unclear.Post-injury management follows similar recommendations to other soft tissue injuries, with a graded progression through stages of rehabilitation to full return to training and then competition, based on symptoms and clinical signs to guide the individual speed of the recovery journey. Evidence favoring surgical repair is conflicting and limited to specific injury sub-types (e.g. proximal avulsions). Further research is needed on specific rehabilitation components and progression criteria, where more individualized approaches could address the high rates of recurrent HMI. Prognostically, a combination of physical examination and magnetic resonance imaging (MRI) seems superior to imaging alone when predicting 'recovery duration,' particularly at the individual level.

Injury and illness in short-course triathletes: A systematic review

BACKGROUND

Determining the incidence and prevalence of injury and illness in short-course triathletes would improve understanding of their etiologies and therefore assist in the development and implementation of prevention strategies. This study synthesizes the existing evidence on the incidence and prevalence of injury and illness and summarizes reported injury or illness etiology and risk factors affecting short-course triathletes.

METHODS

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies reporting health problems (injury and illness) in triathletes (all sexes, ages, and experience levels) training and/or competing in short-course distances were included. Six electronic databases (Cochrane Central Register of Controlled Trials, MEDLINE, Embase, APA PsychINFO, Web of Science Core Collection, and SPORTDiscus) were searched. Risk of bias was independently assessed by 2 reviewers using the Newcastle-Ottawa Quality Assessment Scale. Two authors independently completed data extraction.

RESULTS

The search yielded 7998 studies, with 42 studies eligible for inclusion. Twenty-three studies investigated injuries, 24 studies investigated illnesses, and 5 studies investigated both injuries and illnesses. The injury incidence rate ranged 15.7-24.3 per 1000 athlete exposures, and the illness incidence rate ranged 1.8-13.1 per 1000 athlete days. Injury and illness prevalence ranged between 2%-15% and 6%-84%, respectively. Most injuries reported occurred during running (45%-92%), and the most frequently reported illnesses affected the gastrointestinal (7%-70%), cardiovascular (14%-59%), and respiratory systems (5%-60%).

CONCLUSION

The most frequently reported health problems in short-course triathletes were: overuse and lower limb injuries associated with running; gastrointestinal illnesses and altered cardiac function, primarily attributable to environmental factors; and respiratory illness mostly caused by infection.

Lost in transition: Exploring injury risk in academy footballers shifting between the second and first teams

OBJECTIVES

To compare the injury profiles of football players shifting between second and first teams with those of second- and first-team players, and to examine the opinions of shifting players.

DESIGN

Prospective cohort study.

METHODS

170 male players from Athletic Club (second team = 90, shifting = 20, first team = 60) were followed over eight seasons. Injuries and exposure time were recorded following the FIFA consensus, and 18 shifting players answered a seven-item questionnaire on their experience.

RESULTS

35 % shifting players became full-time first-team players, in contrast to only 8 % of second-team players (odds ratio = 6.4, p < 0.01). There were no differences in the overall injury incidence, but the overall burden of injuries was higher in second-team (172 days lost/1000 h) and shifting players (194 days lost/1000 h) compared with first-team players (114 days lost/1000 h, p < 0.01). Shifting players had a higher burden of knee joint/ligament injuries compared with first-team players (137 vs. 18 days lost/1000 h, p < 0.01) and anterior cruciate ligament (ACL) ruptures (122 vs. 10 days lost/1000 h, p < 0.01). There was a trend towards a higher burden of ACL ruptures in shifting players than in second-team players (122 vs. 41 days lost/1000 h, p = 0.07). Shifting players reported constant pressure and better communication with the second-team coaching staff than with the first-team staff.

CONCLUSIONS

The high burden of injuries in shifting players, particularly from ACL ruptures, highlights the need for action. Ensuring high-quality communication between second- and first-team staff remains a key challenge.

Injury incidence and prevalence in elite short-course triathletes: a 4-year prospective study

OBJECTIVE

To characterise the prevalence, incidence rate (IR) and burden of injuries in elite short-course triathletes over a 4-year training and competition period.

METHODS

Fifty elite Australian triathletes were prospectively monitored for injury during four consecutive seasons (2018-2021). Injuries requiring medical attention were prospectively recorded and further subcategorised according to time loss. The IR and burden (injury IR×mean injury severity) were calculated per 365 athlete days, with sex differences in IR compared using IR ratios (IRR) from negative binomial regression models.

RESULTS

Two hundred and sixty-six injuries were reported in 46 (92.0%) athletes, of which 67.3% resulted in time loss. The injury IR was 1.87 injuries per 365 athlete days (95% CI 1.70 to 2.80), and comparable between sexes (IRR 0.82, 95% CI 0.64 to 1.04, p=0.109). Most injuries (70.7%) were training related. The most frequently injured body sites were the ankle (15.8%), foot (12.4%) and lower leg (12.0%). Bone stress injuries (BSIs) were the most burdensome injury type with 31.38 days of time loss per 365 days (95% CI 24.42 to 38.34). Twenty athletes (40.0%) reported at least one bone stress injury (BSI) (range 0-3). The rate of BSIs in female athletes was three times greater compared with male athletes (IRR 2.99, 95% CI 1.26 to 7.07, p=0.013).

CONCLUSION

Two-thirds of injuries reported in elite short-course triathletes resulted in time loss, with the majority occurring during training activities. Foot, ankle and other lower leg injuries had the highest incidence, with BSIs carrying the highest injury burden. The considerably higher rate of BSI observed in female athletes warrants consideration for future prevention strategies in female triathletes.

Exploring the true burden of a time-loss injury: full vs partial time-loss in elite academy football (soccer)

In football, the number of days without full participation in training/competition is often used as a surrogate measure for time-loss (TL) caused by injury. However, injury management and return-to-play processes frequently include modified participation, which to date has only been recorded through self-reports. This study aims to demonstrate the differentiation between 'full' (no participation in team football) and 'partial' (reduced/modified participation in team football) burden. Injury and exposure data were collected from 118 male elite footballers (U13-U18) over 3 consecutive seasons according to the Football Consensus Statement. TL injury burden was calculated separately as the number of total, 'full' and 'partial' days lost per 1000 h of exposure. Injury burden (137.2 days lost/1000 h, 95% CI 133.4-141.0) was comprised of 23% (31.9 days lost/1000 h, 95% CI 30.1-33.8) partial TL and 77% (105.3 days lost/1000 h, 95% CI 102.0-108.6) full TL burden. Injuries of moderate severity (8-28 days lost) showed 40% of partial TL. TL injury incidence rate (6.6 injuries/1000 h, 95% CI 5.8-7.5), the number of severe injuries (16%), and the distribution of TL and non-TL injuries (56% and 44%) were comparable to other reports in elite youth footballers. Almost one-quarter of the TL injury burden showed that injured players were still included in some team football activities, which, for injuries with TL >7 days, was likely related to the return to play process. Therefore, reporting on partial TL provides insight into the true impact of injury on participation levels.

Ligament Injuries in Professional Male Handball Players: A 6-Year Longitudinal Study

Handball is a sport that involves high-intensity actions throughout the game, such as sprints, jumps, landings, and high-speed, repeated throws. This, along with competitive and tactical factors, congested schedules, and the need to maintain a high level of performance throughout the season, contributes to a high injury rate. This study aimed to analyse ligament injuries in a professional handball team over six consecutive seasons. A total of 68 elite male Spanish handball players participated, with 54 time-loss injuries (i.e., injuries involving at least one day of absence) observed during this study period. Ligament injury information was recorded following the International Olympic Committee consensus statement. The overall incidence was 0.89 ligament injuries per 1000 h of exposure. Additionally, a higher incidence and burden of ligament injuries was observed during match-play compared to training. Most ligament injuries were classified as minor or moderate (i.e., 79.63% of the total), and 46.29% were reinjuries. A significantly higher incidence of ligament injuries was suffered in the lower limbs compared to the upper limbs (0.81 vs. 0.08 ligament injuries per 1000 h; p < 0.001). Specifically, the highest incidence was observed in the anterior talofibular ligament of the ankle (0.57 injuries per 1000 h of exposure), while the greatest burden was related to the anterior cruciate ligament (24.08 absence days per 1000 h of exposure). This study provides an overview of ligament injuries among professional handball players, highlighting the need to implement strategies with positive effects during competition (e.g., specific activation strategies or training programmes based on strength and balance) and to reduce injury recurrences.

Prevalence and incidence of health problems and their characteristics in Brazilian para athletes: A one-season single-center prospective pilot study

BACKGROUND

Para athletes experience high prevalence and incidence of health problems related to sport. Despite this, there are few longitudinal studies.

OBJECTIVE

To describe the characteristics, prevalence, incidence, and severity of health problems in para athletes from one of the Brazilian Paralympic Reference Centers during a sports season and to compare the prevalence of health problems between para athletics, para powerlifting, and para swimming.

METHODS

This prospective pilot study was conducted from October 2019 to March 2020. The Oslo Sports Trauma Research Center Questionnaire on Health Problems was used to record injuries and illnesses every week for 24 weeks. The characteristics, prevalence, incidence, and severity of health problems were described for each modality. The prevalence of health problems was compared among the three sport modalities.

RESULTS

Thirty-five para athletes participated. Most of the injuries occurred in the shoulder, and most illnesses caused respiratory and gastrointestinal symptoms. The average weekly prevalence and the incidence rate of health problems were 40.6% (95% CI 17.0-64.4) and 12.7 (95% CI 9.6-15.9) per 1000 athlete hours, respectively. Para powerlifting had the highest prevalence of all and substantial health problems; para swimming had the lowest prevalence of injuries; and para athletics had the lowest prevalence of illnesses.

CONCLUSIONS

This group of Brazilian para athletes showed a high prevalence and incidence of health problems throughout the season. Para athletics, para powerlifting, and para swimming each had a different prevalence of injuries and illnesses.

Injury patterns in Swedish elite female and male ice hockey - A cross-sectional comparison of past-season's injuries

OBJECTIVES

To describe and compare seasonal prevalence, anatomical location, severity, and onset of injuries between female and male elite ice hockey players.

DESIGN

Cross-sectional survey study.

SETTING

Elite ice hockey.

PARTICIPANTS

Swedish elite ice hockey players (170 females & 190 males).

MAIN OUTCOME MEASURES

Past season injuries reported on a modified version of the Oslo Sports Trauma Research Center overuse injury questionnaire. Proportions of players who experienced any and substantial problems, as well as respective injury severity scores were presented and compared between sexes.

RESULTS

Highest seasonal prevalence was reported for hip/groin [31.1% (n = 112)], lower back [24.2% (n = 87)], and shoulder injuries [23.6% (n = 85)]. Prevalence of injuries was approximately similar between sexes. Substantial injuries were most prevalent in the hip/groin (13.3% [n = 48]) and knee (18.6% [n = 67]) region. Females reported a higher proportion of substantial hip/groin injuries. Most reported injuries were acute except for hip/groin and lower back injuries (74.4% and 81.8% due to overuse).

CONCLUSION

Seasonal prevalence of injuries in elite ice hockey players were comparable between sexes. Acute injuries were most common but hip/groin as well as lower back injuries were predominantly due to overuse. The highest reported prevalence was found for hip and groin-, lower back-, and shoulder injuries.

The Football Association Injury and Illness Surveillance Study: The Incidence, Burden and Severity of Injuries and Illness in Men's and Women's International Football

OBJECTIVES

To determine the incidence and characteristics of injury and illness in English men's and women's senior and youth international football.

METHODS

Time-loss injuries and illnesses, alongside match and training exposure, were collected across 8 seasons (2012-2020) in youth (U15, U16, U17, U18, U19) and senior (U20, U21, U23, senior) English men's and women's international teams. Analysis of incidence, burden, and severity of injury and illness was completed. Sex-specific comparisons were made between the senior and youth groups, and across the 8 seasons of data collection.

RESULTS

In men's international football, 535 injuries were recorded (216 senior; 319 youth) during 73,326 h of exposure. Overall, match injury incidence (31.1 ± 10.8 injuries/1000 h) and burden (454.0 ± 195.9 d absent/1000 h) were greater than training injury incidence (4.0 ± 1.0 injuries/1000 h) and burden (51.0 ± 21.8 d absent/1000 h) (both P < 0.001). In women's international football, 503 injuries were recorded (senior: 177; youth: 326) during 80,766 h of exposure and match injury incidence (27.6 ± 11.3 injuries/1000 h) and burden (506.7 ± 350.2 days absent/1000 h) were greater than training injury incidence (5.1 ± 1.8 injuries/1000 h) and burden (87.6 ± 32.8 days absent/1000 h) (both P < 0.001). In women's international football, a group × season interaction was observed for training injury incidence (P = 0.021), with the senior group recording a greater training injury incidence during the 2015-2016 season compared to the youth group (14.4 vs 5.7 injuries/1000 h; P = 0.022). There was no difference in injury severity between match and training for men's (P = 0.965) and women's (P = 0.064) international football.

CONCLUSIONS

The findings provide a comprehensive examination of injury and illness in English men's and women's senior and youth international football. Practitioners will be able to benchmark their team's injury and illness incidence and characteristics to the match-play and training information provided in the present study.

Injuries in male youth football: a one season prospective cohort study of 223 Danish elite players

Objectives

This study prospectively investigated injury prevalence, incidence, and burden in male elite under-17 football players (N = 223) during a full season.

Methods

The players weekly completed a standardized web-based injury survey (OSTRC-H2) and a physical exposure report throughout the study.

Results

Average weekly response rate was 89.5%. Football exposure accounted for 52.4% of total physical exposure. On average (±SD), the players participated in individual football, strength, and rehabilitation practices for 1.2 ± 1.5, 3.0 ± .2.1, and 1.9 ± 3.4 h/week, respectively. In total, 742 health problems were reported. Mean weekly prevalence of health problems, injuries and illnesses were 20.1%, 16.5% and 3.8%, respectively. The injury incidence per 1,000 h of football exposure, match play and team practice were 8.28 (95% CI: 7.54-9.08), 16.77 (95% CI: 13.65-20.4), and 7.24 (95% CI: 6.5-8.04), respectively. Sudden-onset and gradual-onset injuries accounted for 36.7% and 43.4% of the total proportion of health problems. Hip/groin injuries had the highest incidence (1.58/1,000 h), whereas knee injuries had the highest burden (20.86 days lost/1,000 h). On average, the players experienced 3.33 health problems (average duration: 7.8 days). On average pr. player, 2.7 (95% CI: 2.2-3.3) wks of football exposure were lost.

Conclusion

Sudden and gradual-onset injuries influenced player availability during the season. Health problem prevalence fluctuated markedly, and injury incidence was higher during match play than training. The players had substantial volumes of training beyond football-specific training and matches. Our findings could assist medical and sports science practitioneers in enhancing training and recovery processes to maximize player availability.

Is a Maximal Strength-Training Program Effective on Physical Fitness, Injury Incidence, and Injury Burden in Semi-Professional Soccer Players? A Randomized Controlled Trial

The aims of the study were to analyze the effects of a 12-week maximal strength- training program on injury incidence, injury burden, and physical fitness in semi-professional soccer players and to compare the perceived exertion load and well-being state between injured and non-injured soccer players. Twenty semi-professional male soccer players participated in this study. Participants were randomly allocated to an experimental group (EG, n = 10 players), who performed a maximal strength-training program, or to a control group (CG, n = 10 players), who only performed their regular soccer training. Physical fitness was measured at baseline and after the training program. In addition, the injury incidence, burden, training/match load, and the state of well-being of the players were recorded. The EG showed significant improvements in vertical jumps, change in direction ability, linear sprints, repeated sprint ability, isometric strength (p < 0.003; effect size = 1.78-11.86), and quadriceps-hamstring imbalance in both legs (p < 0.001; effect size = 2.37-3.71) in comparison to the CG. In addition, the EG players showed a significantly (p < 0.05) lower injury burden (p < 0.001, relative risk = 5.05, 95% confidence interval = 3.27-7.79). This study demonstrated the beneficial effects of a 12-week maximal strength-training program on physical fitness attributes and injury burden in semi-professional soccer players.

Not All Injuries Are the Same: Different Patterns in Sports Injuries and Their Psychosocial Correlates

Sports injuries are ubiquitous and can have far-reaching consequences for athletes (e.g., health, performance). Previous studies have examined various psychosocial influencing factors (e.g., stress), but have mostly focused on only one or two injury characteristics (e.g., frequency), neglecting the broader injury pattern. Thus, the present study aimed to obtain a more differentiated picture of potentially different injury patterns and related profiles of psychosocial factors. We investigated a sample of 213 athletes from a cross-sectional online study. Current injury status, frequency, severity, chronicity, medical treatment, and rehabilitation measures were subjected to cluster analysis indicating a 3-cluster solution with predominantly chronically injured athletes (n = 54), athletes not seeking treatment (n = 62), and athletes utilizing medical treatment and rehabilitation (n = 97). Building on the Model of Stress and Athletic Injury, we subsequently conducted three multivariate analyses of variance (MANOVAs) to examine whether the obtained clusters differed in terms of personality factors (e.g., athletic identity), history of stressors (e.g., life events), and coping resources (e.g., self-compassion). We observed significant differences in all three categories of psychosocial variables implying different intervention possibilities for different injury patterns in the future.

Risk factors for acute ankle sprains in field-based, team contact sports: a systematic review of prospective etiological studies

OBJECTIVE

The aim of this systematic review was to identify prospectively measured ankle sprain risk factors in field-based team contact sports.

METHODS

Eight databases including SPORTDiscus, CINAHL Complete, MEDLINE (EBSCO), Education Source, Web of Science, Scopus, Embase, and Pubmed were searched using specific Boolean terms. A modified-CASP diagnostic test assessed the quality of the included studies. Extensive data extraction included but was not limited to injury definition, protocols for injury diagnosis and recording, and outcomes associated with ankle sprain.

RESULTS

4012 records were returned from the online search and 17 studies met the inclusion criteria for this review. Twelve different risk factors including anatomic alignment of the foot and ankle, joint laxity, height, mass, BMI (body mass index), age, ankle strength, hip strength, single leg landing performance (ground reaction force, pelvic internal rotation, and knee varus), and single leg reach were all found to be associated with ankle sprain incidence. Injury definitions and methods of diagnosis and recording varied across the 17 studies.

CONCLUSION

This review updates the literature on prospective risk factors for ankle sprain in a specific population rather than heterogeneous cohorts previously studied. From more than 20 categories of risk factors investigated for ankle sprain association across 17 studies in field-based team contact sports, 12 variables were found to be associated with increased incidence of ankle sprain. In order to reduce the risk of ankle sprain, BMI, ankle plantar and dorsiflexion strength, hip strength, and single leg landing performance should be factored in to athlete assessment and subsequent program design. More studies utilizing standardized definitions and methods of recording and reporting are needed. Future prospective etiological studies will allow strength and conditioning coaches, physiotherapists, and physicians to apply specific training principles to reduce the risk and occurrence of ankle sprain injuries.

How Does Age Affect Injury Characteristics in Young Elite Footballers?-A Prospective Cohort Study of a German Youth Academy

BACKGROUND

Little is known about age-related changes in injury characteristics and burden, and existing data are inconsistent, highlighting the need for new studies on this topic. This study aimed to describe age-related injury risk, severity and burden in a German elite youth football academy.

METHODS

A prospective cohort study was conducted in the 2012/2013 season, reporting 109 time-loss injuries among 138 young athletes playing at an elite football academy in Germany. For the most severe injuries, the injury burden in the different age groups was considered separately.

RESULTS

Athletes missed a total of 2536 days of exposure, resulting in an overall incidence of 2.6 per 1000 h (1.7-3.0; 95% CI) and a burden of 60.6 days lost per 1000 h (40.8-80.3; 95% CI). The incidence and burden of joint sprains and muscle injuries were higher in the older age groups. Physeal injuries peaked in the U14 age group during the pubertal growth spurt. Bone injuries and contusions showed no age trend.

CONCLUSION

Injury characteristics vary with age. The overall incidence, severity and burden of injuries increased with the age of the athletes. To ensure the optimal development of young athletes, it is important to be aware of the differences in injury susceptibility between age groups in order to implement tailored prevention programmes.

Surveillance is the first step to preventing injury among fast jet aircrew: results of a 2-year prospective cohort study

OBJECTIVES

Injury surveillance is imperative for injury prevention but difficult in military populations. Our objective was to accurately describe the pattern of musculoskeletal complaints among Royal Australian Air Force (RAAF) fast jet aircrew (FJA) using the validated University of Canberra Fast Jet Aircrew Musculoskeletal Questionnaire (UC-FJAMQ) over a 2-year period, and determine injury burden on the workforce and operational capability.

METHODS

306 RAAF FJA were monitored over a 2-year period (4×5 month reporting periods). Musculoskeletal complaint episodes (MCEs) were captured weekly using the UC-FJAMQ. Time loss episodes (TLEs) were captured from the UC-FJAMQ and injury registers completed by embedded physiotherapists. Cumulative severity and operational impact scores from the UC-FJAMQ, and time loss duration, were used to describe severity and calculate burden.

RESULTS

Mean weekly UC-FJAMQ response rate was 62%. 1012 MCEs were captured, with a mean weekly prevalence of 14.9% (95% CI 14.2-15.6), and incidence of 4.1 episodes per person-year (95% CI 3.9-4.4). A total of 145 TLEs were captured, with a mean 5-month prevalence of 12.4% (range 8.9-15.3%), and incidence of 0.37 episodes per person-year (95% CI 0.31-0.43). Spinal regions accounted for 81% of MCEs and contributed 76% and 85% of burden in relation to cumulative severity and operational impact, respectively. 57% of TLE burden came from spinal regions.

CONCLUSIONS

Despite modest weekly UC-FJAMQ response rates, musculoskeletal complaints were shown to be widespread and negatively impact operational capability. Future injury prevention efforts among FJA should focus on spinal regions, particularly the neck.

The impact of a multicomponent training program on physical fitness and joint injuries in Spanish male professional soccer players

This study aimed to assess the effects of a multicomponent training program (ProSAS) on selected measures of physical fitness and joint injuries in Spanish male professional soccer players. Twenty-six professional soccer players (age: 25.2 ± 3.1 years) were randomly assigned to either the experimental (EG; n = 16) or control group (CG; n = 10). Y-balance test (YBT), Single leg countermovement jump (SLCMJ), Single leg hop for distance test (SLH), Side-hop test (SH), Speedy jump test (SpJ), Agility T-test (TT) and Lower extremity functional test (LEFT) were performed before and after an 8-weeks training period. Additionally, any joint injury occurring during the intervention period were recorded. Significant improvements in the EG in all tests (p = 0.001 to p = 0.014), except for SLCMJ (p = 0.632) with the dominant leg were observed. CG displayed decreases in SLCMJ with the non-dominant leg (p = 0.014), SH for both legs (p = 0.001 to p = 0.050), TT (p = 0.005), and LEFT (p = 0.001). Inter-groups differences revealed better results for the EG in all variables (p = 0.001 to p = 0.008) except from SLCMJd (p = 0.555). Moreover, the EG exhibited lower joint injury incidence and burden compared to the CG (p < 0.05). These findings suggest that the ProSAS is an effective multicomponent program to improve variables related to risk of joint injuries, and consequently, to reduce the incidence and burden of these injuries in professional soccer players.

Hamstring Injury Treatments and Management in Athletes: A Systematic Review of the Current Literature

BACKGROUND

The field of sports medicine presents a varied landscape of research on hamstring injuries in athletes, characterized by inconclusive and sometimes conflicting findings on effective treatment and rehabilitation strategies. This discordance prompted the current systematic investigation.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed for conducting the systematic review. Multiple international bibliometric databases (Scopus, PubMed, Web of Science, and Embase) were searched to identify studies evaluating any treatment option for the management of hamstring injuries in athletes. Eligible studies were appraised for quality using Joanna Briggs Institute and Risk of Bias 2 tools.

RESULTS

A total of 30 studies with 1,195 participants were included. Of the reviewed studies, treatments varied from aggressive rehabilitation, platelet-rich plasma (PRP) injections, manual techniques, various exercise protocols to modalities like high-power laser and nonsteroidal anti-inflammatory drugs. Evidence suggested benefits from treatments like extensive muscle lengthening during eccentric actions, progressive agility, and trunk stabilization. PRP injections produced mixed results regarding return to sport and reinjury rates. Stretching exercises, sometimes combined with cryotherapy, showed benefits.

CONCLUSION

Treatments for hamstring injuries exhibit varied efficacy. Although rest, ice, compression, and elevation remains essential for acute management, rehabilitation focusing on muscle strengthening and flexibility is crucial. The potential benefits of PRP injections, especially for chronic cases, require more conclusive research. A comprehensive approach, combining evidence-based practices and patient-centric factors, is vital for effective management and recovery.

LEVEL OF EVIDENCE

Level IV. See Instructions for Authors for a complete description of levels of evidence.

Comparison of Strength and Power Characteristics Before ACL Rupture and at the End of Rehabilitation Before Return to Sport in Professional Soccer Players

BACKGROUND

Strength and power is often reduced on the involved versus contralateral limb and healthy controls after anterior cruciate ligament (ACL) reconstruction, but no study has compared with preinjury values at the time of return to sport (RTS).

HYPOTHESIS

Divergent recovery patterns in strength and power characteristics will be present at RTS relative to preinjury baseline data and healthy matched controls.

STUDY DESIGN

Cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Isokinetic strength tests, bilateral and single-leg countermovement jumps (CMJ; SLCMJ) were measured before ACL rupture in 20 professional soccer players. These then had surgical reconstruction (ACL group) and completed follow-up testing before RTS. Healthy controls (uninjured group) were tested at the same time as the ACL group preinjury. Values recorded at RTS of the ACL group were compared with preinjury. We also compared the uninjured and ACL groups at baseline and RTS.

RESULTS

Compared with preinjury, ACL normalized quadriceps peak torque of the involved limb (difference = -7%), SLCMJ height (difference = -12.08%), and Reactive Strength Index modified (RSImod) (difference = -5.04%) were reduced after ACL reconstruction. No significant reductions in CMJ height, RSImod, and relative peak power were indicated at RTS in the ACL group when compared with preinjury values, but deficits were present relative to controls. The uninvolved limb improved quadriceps (difference = 9.34%) and hamstring strength (difference = 7.36%) from preinjury to RTS. No significant differences from baseline were shown in SLCMJ height, power, and reactive strength of the uninvolved limb after ACL reconstruction.

CONCLUSION

Strength and power in professional soccer players at RTS after ACL reconstruction were often reduced compared with preinjury values and matched healthy controls.

CLINICAL RELEVANCE

Deficits were more apparent in the SLCMJ, suggesting that dynamic and multijoint unilateral force production is an important component of rehabilitation. Use of the uninvolved limb and normative data to determine recovery may not always be appropriate.

Fatigue-induced Landing Alterations in ACL Reconstructed Athletes after Return-to-Sport

At the time of return-to-sport, anterior cruciate ligament reconstructed athletes still show altered neuromechanics in their injured leg during single leg hopping tasks. Part of these alterations can be magnified when these athletes are fatigued. So far, little is known whether fatigue-induced landing alterations persist after return-to-sport. Therefore, the aim of this study was to evaluate whether these alterations persist in the six months following return-to-sport. Sixteen anterior cruciate ligament reconstructed athletes performed five unilateral hop tasks before and after a fatigue protocol. The hop tasks were executed at three different time points (return-to-sport, 3 and 6 months post-return-to-sport). A 2-by-3 repeated measures ANOVA was performed to evaluate whether fatigue-induced landing alterations persisted 3 and 6 months following return-to-sport. At 6 months following return-to-sport, fatigue still induces a reduction in hamstring medialis activation and an increase in the knee abduction moment during a vertical hop with 90-degree inward rotation. Most fatigue-induced landing alterations present at the time of return-to-sport normalize after resumption of sports activities. However, a larger knee abduction moment in the injured leg after resumption of sports activities can still be observed.

Reliability and Measurement Error of the Qualitative Analysis of Single Leg Loading (QASLS) Tool For Unilateral Tasks

Background

Movement quality assessment is popular within clinical and sporting practice, due to the contribution diminished or suboptimal movement quality is believed to have on musculoskeletal (MSK) injury risk. Various movement quality assessments exist, many are limited to bilateral or jumping movements evaluation. Qualitative analysis of single leg loading (QASLS) is a new clinical assessment tool for unilateral tasks that utilizes a dichotomous scoring system of ten questions relating to the segmental body regions of the trunk, lower and upper limb.

Purpose

To determine the intra and inter-rater, within- and between-session reliability of the QASLS tool during two unilateral movement tasks, and provide insight to measurement error and smallest detectable difference (SDD).

Study Design

Reliability Study.

Methods

Fifteen healthy females (mean age 19 years SD2; height 167 cm, +/- 6; weight 56 kg, +/- 6) completed two unilateral tasks, single leg squat (SLS) and single leg landing (SLL), within session data collection occurred on the same day, with between session data collection occurring seven days later. Tasks were scored with the QASLS tool via video playback. Intra-Class correlation coefficients (ICCk,3) were used to measure within and between session reliability, and Kappa coefficients and percentage of exact agreement (PEA%) were used to determine intra and inter-rater reliability. Standard error of measurement (SEM) and the SDD for the compound score of each limb was calculated.

Results

Within session reliability of QASLS scores was good (ICC = 0.82-0.86) for SLS and moderate (ICC = 0.67-0.87) for SLL. Between session reliability was moderate (ICC = 0.69-0.87) for SLS and excellent (ICC = 0.92-0.93) for SLL. SEM was less than 1 point, and SDD for compound score ranging from 1.0-2.5 points. Intra-rater agreement of compound QASLS score was near perfect (k = 0.85-100; PEA% 90-100%) and agreement of individual components was substantial- near perfect (k = 0.13-0.74; PEA% 78-100%). Inter-rater agreement for compound QASLS scores ranged from non-substantial (k = 0.13-0.74; PEA% 43.3-90%) for SLS and non-slight (k =0.03-0.17; PEA% 43.3-60%) for SLL.

Conclusions

The QASLS movement analysis tool can be used to analyze movement quality during two unilateral loading tasks with moderate to excellent within and between session reliability. PEA% was acceptable for inter-rater agreement, however rater education training is recommended to develop more acceptable levels of reliability.

Level of Evidence

3.

Analysis of injuries during the 2019 Rink Hockey World Championship

OBJECTIVES

The purpose of this study is to describe the incidence and characteristics of injuries at the 2019 Rink Hockey World Championship.

METHODS

A cross-sectional study was performed among rink hockey athletes from three National Teams (Argentina, Portugal, and Spain). All injuries were reported by the medical staff of each National Team during the preparation period and the competition in the 2019 World Championship (Barcelona, Spain). Injury rate was calculated as the number of injuries per 1000 hours of player-hours of exposure.

RESULTS

A total of 91 players (n = 61, 67% male; and n = 30, 33% female) participated in the study: 31 Senior Male (34%), 30 Senior Female (33%), and 30 Under-19 Male (33%). A total of 54 games were played by 9 teams from 3 countries, comprising of 4562 and 4380 hours of total athletic game and training exposure recorded, respectively. Fifty-one injuries (20 injuries with time-loss and 31 medical attention -injuries with no time-loss) were reported. The overall injury incidence rate was 11.2/1000 hours (95% CI, 8.5-14.7). The injury incidence during games (27.5; 95% CI, 11.6-65.2) was higher than the injury incidence during training sessions (3.4; 95% CI, 2-5.7). The incidence rate for game for the entire study period was 8.19 times higher (95% CI, 2.61-21.36) than that for training. The global injury burden was 45.4 days/1000 hours for a total exposure time. Acute was the most frequently documented onset and the non-contact was the most common mechanism. The most frequently reported injuries were head contusion (n = 5, 25%), followed by thigh injuries (n = 3, 15%).

CONCLUSIONS

The injury incidence reported in a Rink Hockey international competition was 11.2/1000 hours. The risk of injury was higher during games than during training. Prevention strategies for injuries in these kinds of championships may be worth discussing. The craniofacial injuries were the most frequently reported.

Year-round longitudinal health surveillance in UK Olympic Summer Sport Athletes 2016-2019

OBJECTIVES

To identify the priority injury and illness types across UK summer Olympic World Class Programme sports to inform development, implementation and evaluation of associated injury risk mitigation and management initiatives.

METHODS

Four years (2016-2019) of electronic medical records of 1247 athletes from 22 sports were analysed and reported using methods based on the 2020 International Olympic Committee consensus statement for epidemiological recording and reporting.

RESULTS

3562 injuries and 1218 illness were recorded, accounting for 146 156 and 27 442 time-loss days. Overall, 814 (65%) athletes reported at least one injury, while 517 (41%) reported at least one illness. There were 1.3 injuries per athlete year resulting in a mean burden of 54.1 days per athlete year. The lumbar/pelvis, knee, ankle and shoulder body regions had the highest incidence and burden. Athletes reported 0.5 illnesses per athlete year, resulting in a mean burden of 10.4 days per athlete year, with most composed of respiratory illness and gastroenteritis. Injuries within sport groups were representative of the injury risk profile for those sports (eg, knee, hand and head injuries had the highest incidence in combat sports), but respiratory illnesses were consistently the greatest problem for each sport group.

CONCLUSIONS

To optimise availability for training and performance, systematic risk mitigation and management initiatives should target priority injury problems occurring in the lumbar/pelvis, knee, ankle and shoulder, and respiratory illness. Follow-up analysis should include identification of sport-specific priority health problems and associated risk factors.

The effects of hip- vs. knee-dominant hamstring exercise on biceps femoris morphology, strength, and sprint performance: a randomized intervention trial protocol

BACKGROUND

The hamstrings are an important muscle group that contribute to horizontal force during sprint acceleration and are also the most injured muscle group in running-based sports. Given the significant time loss associated with hamstrings injury and impaired sprinting performance following return to sport, identifying exercises that drive adaptations that are both protective of strain injury and beneficial to sprint performance is important for the strength and conditioning professional. This paper describes the study protocol investigating the effects of a 6-week training program using either the hip-dominant Romanian deadlift (RDL) or the knee-dominant Nordic hamstring exercise (NHE) on hamstring strain injury risk factors and sprint performance.

METHODS

A permuted block randomized (1:1 allocation) intervention trial will be conducted involving young, physically-active men and women. A target sample size of 32 will be recruited and enrolled participants will undergo baseline testing involving extended-field-of-view ultrasound imaging and shear wave elastography of the biceps femoris long head muscle, maximal hamstrings strength testing in both the RDL and NHE, and on-field sprint performance and biomechanics. Participants will complete the 6-week training intervention using either the RDL or NHE, according to group allocation. Baseline testing will be repeated at the end of the 6-week intervention followed by 2 weeks of detraining and a final testing session. The primary outcome will be regional changes in fascicle length with secondary outcomes including pennation angle, muscle cross sectional area, hamstring strength, and maximal sprint performance and biomechanics. An exploratory aim will determine changes in shear wave velocity.

DISCUSSION

Despite extensive research showing the benefits of the NHE on reducing hamstring strain injury risk, alternative exercises, such as the RDL, may offer similar or potentially even greater benefits. The findings of this study will aim to inform future researchers and practitioners investigating alternatives to the NHE, such as the RDL, in terms of their effectiveness in reducing rates of hamstring strain injury in larger scale prospective intervention studies.

TRIAL REGISTRATION

The trial is prospectively registered on ClinicalTrials.gov (NCT05455346; July 15, 2022).

The associations between unilateral leg strength, asymmetry and injury in sub-elite Rugby League players

OBJECTIVES

The aim of this study was to analyse the relationship between unilateral leg strength, associated asymmetries and the injuries suffered by sub-elite Rugby League (RL) players in one competitive season.

DESIGN

A prospective cohort design was used.

METHOD

Unilateral leg strength was measured using the rear foot elevated split squat five repetition maximum test. Injuries were recorded using the Orchard classification system and were used to quantify relative risk (RR), mean severity, burden, player availability and survival time.

RESULTS

No measures of leg strength were related to RR, relative leg strength was found to have a significant, but not meaningful correlation with total time lost to lower body injury, lower body injury burden and lower body injury survival time.

CONCLUSIONS

The data from the current study indicates a possible positive effect of increasing relative leg strength for injury outcomes in sub-elite RL players. This supports a heuristic that multi-joint lower body strength training for RL players has a potential dual effect of enhancing physical performance and reducing injury time loss, with minimal risk of harm.

Association Between Magnetic Resonance Imaging Findings and Time to Return to Sport After Muscle Injuries in High-Level Youth Athletes

OBJECTIVE

To describe the relationship between magnetic resonance imaging (MRI) findings and time to return to sport (RTS) from muscle injuries in youth athletes.

DESIGN

Prospective collection of injury surveillance data over 6 seasons (2014-2015 to 2019-2020) and reanalysis of MRIs by a radiologist blinded to RTS time after the data collection period.

SETTING

National sports academy and sports medicine hospital.

PARTICIPANTS

Male youth (11-19 years) athletes participating in the football (soccer) or athletics (track and field) programs with a muscle injury.

INDEPENDENT VARIABLES

Magnetic resonance imaging findings (eg, grade and location) in time-loss muscle injuries.

MAIN OUTCOME VARIABLES

Injury incidence, distributions, and RTS time.

RESULTS

In total, 353 time-loss muscle injuries were recorded for 1089 athlete-seasons, of which 85 satisfied our inclusion criteria (MRI within 14 days). Return to sport time was significantly longer for reinjuries compared with index injuries. Associations between MRI findings and RTS time were specific to the muscle group, with significant differences in RTS time observed between categories of structure, location, and grade. The largest number of injuries was to the hamstrings (n = 46), where injuries involving the tendon were more severe than those involving the myotendinous junction and muscle, proximal injuries were more severe than mid-portion and distal, and longer RTS time was observed for higher injury grade ( P < 0.05).

CONCLUSIONS

Muscle injuries in youth are diverse and cannot be treated as a single injury type. Specific injury durations can be expected depending on injury characteristics such as reinjury, location, structure, and grade.

Injuries in elite road cyclists during competition in one UCI WorldTour season: a prospective epidemiological study of incidence and injury burden

METHODS

Fifty-four male athletes from two different teams were involved. Accidents and injuries were recorded immediately after the incident by a team physician present at every race. Exposure, location, type and cause of injury have been recorded. Incidence was calculated. Severity was measured as a cumulative severity score and burden depicted in a risk matrix.

RESULTS

Total time of exposure was 12537 hours over 3524 athlete days and 544002 kilometers of racing. 98 accidents were recorded, with 83 leading to injury. The total number of recorded injuries was 193. Injury incidence for all injuries was 54,8 (±SD 47,7-62,8) /1000 athlete days, 15,4 (±SD 13,4-17,7) /1000 athlete hours and 35,5 (±SD 30,8-40,8) /100.000 km raced. By far the most frequent types of injury were hematomas, contusions and bruising (n = 141, 73%) followed by lacerations (n = 22; 11,4%). Most injuries affected the arm and elbow (n = 34, 17,6%) followed by the shoulder and clavicle (n = 28, 14,5%) and occurred with contact (79%). Fractures pose a high injury burden due to long time loss, whereas hematomas, contusions and bruising showed the highest incidence numbers but comparably less time loss.

CONCLUSION

Road cyclists' injuries have been underestimated in previous studies. Hematomas, contusions and bruising pose the highest number of injuries with a broad degree of severity and range of injury burden. Fractures are less common but show the highest injury burden. The upper extremities are involved the most.

Are Football Players More Prone to Muscle Injury after COVID-19 Infection? The "Italian Injury Study" during the Serie a Championship

INTRODUCTION

Football was the first sport to resume competitions after the coronavirus disease 2019 (COVID-19) lockdown and promptly the hypothesis was raised of a potential relationship between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and musculoskeletal injuries in athletes. This study aimed to confirm the association between SARS-CoV-2 infection and muscle strain injury in a large population of elite football players and to investigate if the COVID-19 severity level could affect the risk of injury.

METHODS

A retrospective cohort study involving 15 Italian professional male football teams was performed during the Italian Serie A 2020-2021 season. Injuries and SARS-CoV-2 positivity data were collected by team doctors through an online database.

RESULTS

Of the 433 included players, we observed 173 SARS-CoV-2 infections and 332 indirect muscle strains. COVID-19 episodes mostly belonged to severity level I and II. The injury risk significantly increased after a COVID-19 event, by 36% (HR = 1.36, CI_95% 1.05; 1.77, p-value = 0.02). The injury burden demonstrated an 86% increase (ratio = 1.86, CI_95% 1.21; 2.86, p-value = 0.005) in the COVID-19 severity level II/III versus players without a previous SARS-CoV-2 infection, while level I (asymptomatic) patients showed a similar average burden (ratio = 0.92, CI_95% 0.54; 1.58, p-value = 0.77). A significantly higher proportion of muscle-tendon junction injuries (40.6% vs. 27.1%, difference = 13.5%, CI_95% 0.002%; 26.9%, p-value = 0.047) was found when comparing level II/III versus Non-COVID-19.

CONCLUSIONS

This study confirms the correlation between SARS-CoV-2 infection and indirect muscle injuries and highlights how the severity of the infection would represent an additional risk factor.

Effectiveness of a warm-up programme to reduce injuries in youth volleyball players: a quasi-experiment

OBJECTIVES

To establish the effectiveness of the 'VolleyVeilig' programme on reducing injury rate, injury burden and injury severity in youth volleyball players.

METHODS

We conducted a quasi-experimental prospective study over one season of youth volleyball. After randomisation by competition region, we instructed 31 control teams (236 children, average age 12.58±1.66) to use their usual warm-up routine. The 'VolleyVeilig' programme was provided to 35 intervention teams (282 children, average age 12.90±1.59). This programme had to be used during each warm-up before training sessions and matches. We sent a weekly survey to all coaches, collecting data on each player's volleyball exposure and injuries sustained. Multilevel analyses estimated differences in injury rates and burden between both groups, and we used non-parametric bootstrapping to compare the differences in injury numbers and injury severity.

RESULTS

We found an overall reduction in injury rates of 30% for intervention teams (HR 0.72; 95% CI 0.39 to 1.33). Detailed analyses revealed differences for acute (HR 0.58; 95% CI 0.34 to 0.97) and upper extremity injuries (HR 0.41; 95% CI 0.20 to 0.83). Compared with control teams, the intervention teams had a relative injury burden of 0.39 (95% CI 0.30 to 0.52) and a relative injury severity of 0.49 (95% CI 0.03 to 0.95). Only 44% of teams fully adhered to the intervention.

CONCLUSION

We established that the 'VolleyVeilig' programme was associated with reduced acute and upper extremity injury rates and lower injury burden and severity in youth volleyball players. While we advise implementation of the programme, programme updates to improve adherence are needed.

The burden of injuries according to maturity status and timing: A two-decade study with 110 growth curves in an elite football academy

Injuries have a negative impact on the development of football players. Maturation is a potential risk factor for football injuries but available data on this topic provide limited evidence due to methodological shortcomings. The aim of this study was to describe the injury burden of male academy football players according to growth curve-derived maturity status and timing. Injury and growth data were collected from 2000 to 2020. Longitudinal height records for 110 individual players were fitted with the Super-Imposition by Translation and Rotation model to estimate age at peak height velocity (PHV). Players were clustered according to maturity status (pre-, circa-, post-PHV, or adults) and timing (early, on-time, late maturers). Overall and specific injury burdens (days lost/player-season) and rate ratios for comparisons between groups were calculated. Overall injury burden increased with advanced maturity status; pre-PHV players had 3.2-, 3.7-, and 5.5-times lower burden compared with circa-PHV, post-PHV, and adult players, respectively. Growth-related injuries were more burdensome circa-PHV, while muscle and joint/ligament injuries had a higher impact post-PHV and in adults. Further, in the pre-PHV period, late maturers showed lower burden of overall, growth-related, anterior inferior iliac spine osteochondrosis, and knee joint/ligament injuries compared with on-time maturers. In adult players, however, injuries were less burdensome for early maturers than on-time and late maturers. In addition, joint/ligament injuries of adult late maturers were 4.5-times more burdensome than those of early maturers. Therefore, monitoring maturity seems crucial to define each player's maturation profile and facilitate design of targeted injury prevention programmes.Highlights Injury burden is significantly lower in football players at pre-peak height velocity (PHV). Growth-related injuries are most burdensome circa-PHV, while muscle and joint/ligament injuries are more burdensome post-PHV and especially in adults.Before PHV, growth-related and knee joint/ligament injuries have lower burden in players who mature late than those who mature on-time. Adult late maturers have greater burden of overall and joint/ligament injuries than early maturers.Football academies should regularly assess the maturity status and timing of young football players, as the impact of injuries varies with maturation status and timing.Management of the maturity-related injury risk profile, in combination with other relevant factors (training load, neuromuscular and biomechanical factors, physiotherapy, coaching, communication, psychosocial factors …), might help improve the success of player development programmes and protect the health of young football players.

Acute and Overuse, Time-Loss and Non-Time-Loss Lateral Ankle Sprains and Health Care Utilization in Collegiate Student-Athletes

CONTEXT

Health care utilization and the occurrence of non-time-loss (NTL) lateral ankle sprains is not well documented in collegiate athletes but could provide better estimates of injury burden and inform clinician workload.

DESIGN

Descriptive epidemiologic study.

METHODS

Lateral ankle sprain injury occurrence for Division I collegiate student-athletes in a conference with 32 sports representing 732 team seasons was collected during the 2018-2019 through 2020-2021 academic years. Injuries were designated as acute or overuse, and time-loss (TL) or NTL. Associated health care utilization, including athletic training services (AT services), and physician encounters were reported along with anatomical structures involved and season of occurrence.

RESULTS

A total of 1242 lateral ankle sprains were reported over the 3 years from 732 team seasons and 17,431 player seasons, resulting in 12,728 AT services and 370 physician encounters. Most lateral ankle sprains were acute-TL (59.7%), which were associated with the majority of AT services (74.1%) and physician encounters (70.0%). Acute-NTL sprains represented 37.8% of lateral ankle sprains and were associated with 22.3% of AT services and 27.0% of physician encounters. On average, there were 12.7 (5.8) AT services per acute-TL sprain and 6.0 (3.6) per acute-NTL sprain. Most sprains involved "ankle lateral ligaments" (45.6%), and very few were attributed to overuse mechanisms (2.4%).

CONCLUSIONS

Lateral ligament sprains are a common injury across many sports and result in substantial health care utilization from ATs and physicians, including NTL lateral ankle sprains. Although TL injuries were the majority of sprains, a substantial proportion of sprains were NTL and accounted for a considerable proportion of health care utilization.

Peak Height Velocity Affects Injury Burden in Circa-PHV Soccer Players

Growth and maturation are potential risk factors for soccer injuries. This research sought to describe how peak height velocity (PHV) affects overall and specific injury burden in circa- and post-PHV elite academy soccer players. Injuries and growth data collected from 2000 to 2020 were studied retrospectively. Longitudinal height records for 124 players were fitted with the Super-Imposition by Translation and Rotation model to calculate PHV (cm/year) and age at PHV. Players were classified according to PHV percentile (fast:≥75th; average: 25-75th; slow:≤25th) and maturity status (circa- or post-PHV). Overall and specific injury burden (days lost/player-season) and rate ratios for comparisons between groups were calculated based on zero-inflated negative binomial models. Confidence intervals were calculated at the 95% confidence level (CI) and the significance level was set at<0.05. In circa-PHV, players with fast PHV had 2.6 (CI: 1.4-4.8)- and 3.3 (CI:1.3-6.7)-times higher overall burden and 2.9 (CI:1.1-7.1)- and 4.1 (CI: 1.4-15.2)-times higher for growth-related injury burden compared to players with average and slow PHV, respectively. Regular monitoring of growth seems important to detect players at higher risk for being disrupted by growth-related injuries.

Incidence and burden of injury at the Tokyo 2020 Paralympic Games held during the COVID-19 pandemic: a prospective cohort study of 66 045 athlete days

OBJECTIVE

To describe the epidemiology of injuries at the Tokyo 2020 Paralympic Games, including injuries sustained in the new sports of badminton and taekwondo.

METHODS

Injury data were obtained daily via the established web-based injury and illness surveillance system (WEB-IISS; 81 countries, 3836 athletes) and local organising committee medical facilities (81 countries, 567 athletes). Univariate unadjusted incidences (injuries per 1000 athlete days with 95% CIs), injury proportion (IP, %) and injury burden (days lost per 1000 athlete days) are reported.

RESULTS

A total of 4403 athletes (1853 women, 2550 men) from 162 countries were monitored prospectively during the 3-day pre-competition and 12-day competition periods (66 045 athlete days). 386 injuries were reported in 352 athletes (IP=8.0%) with an incidence of 5.8 per 1000 athlete days (95% CI 5.3 to 6.5). Football 5-a-side (17.2), taekwondo (16.0), judo (11.6) and badminton (9.6) had the highest incidence. There was a higher incidence of injuries in the pre-competition period than in the competition period (7.5 vs 5.4; p=0.0053). Acute (sudden onset) injuries and injuries to the shoulder (0.7) and hand/fingers (0.6) were most common. Injury burden was 10.9 (8.6-13.8), with 35% of injuries resulting in time loss from training and competition.

CONCLUSION

Compared with previous Paralympic Games, there was a reduction in injury incidence but higher injury burden at the Tokyo 2020 Paralympic Games. The new sports of taekwondo and badminton had a high injury incidence, with the highest injury burden in taekwondo, compared with other sports. These findings provide epidemiological data to inform injury prevention measures for high-risk sports.

Muscle Architecture, Morphology, and Mechanical and Functional Properties of Biceps Femoris Long Head in Professional Soccer Players with a Prior Healed Injured Hamstring

OBJECTIVE

The aim of the present study was to compare the fascicle length, pennation angle, muscle thickness and stiffness of the biceps femoris long head, and eccentric hamstring strength between injured dominant limbs, injured non-dominant limbs, uninjured dominant limbs and uninjured non-dominant legs in previously injured players, and between dominant and non-dominant legs in uninjured elite soccer players.

MATERIALS AND METHODS

Twenty elite soccer players participated in this study. Ultrasound imaging and MyotonPRO were used to determine the morphological and mechanical properties of the biceps femoris long head. Isokinetic and Nordic hamstring exercises were used to assess eccentric hamstring strength.

RESULTS

Previously injured players showed substantially lower fascicle length and muscle thickness, and significantly higher biceps femoris long head stiffness than uninjured players, without differences between limbs.

CONCLUSION

The morphological and mechanical properties of elite soccer players with hamstring injury history were different from those in uninjured players. The lack of differences between limbs showed that these values are characteristics of individual players that must be considered in the design of programs to prevent BFlh injury.

Development of an Injury Burden Prediction Model in Professional Baseball Pitchers

Background

Baseball injuries are a significant problem and have increased in incidence over the last decade. Reporting injury incidence only gives context to rate but not in relation to severity or injury time loss.

Hypothesis/Purpose

The purpose of this study was to 1) incorporate both modifiable and non-modifiable factors to develop an arm injury burden prediction model in Minor League Baseball (MiLB) pitchers; and 2) understand how the model performs separately on elbow and shoulder injury burden.

Study Design

Prospective longitudinal study.

Methods

The study was conducted from 2013 to 2019 on MiLB pitchers. Pitchers were evaluated in spring training arm for shoulder range of motion and injuries were followed throughout the season. A model to predict arm injury burden was produced using zero inflated negative binomial regression. Internal validation was performed using ten-fold cross validation. Subgroup analyses were performed for elbow and shoulder separately. Model performance was assessed with root mean square error (RMSE), model fit (R2), and calibration with 95% confidence intervals (95% CI).

Results

Two-hundred, ninety-seven pitchers (94 injuries) were included with an injury incidence of 1.15 arm injuries per 1000 athletic exposures. Median days lost to an arm injury was 58 (11, 106). The final model demonstrated good prediction ability (RMSE: 11.9 days, R2: 0.80) and a calibration slope of 0.98 (95% CI: 0.92, 1.04). A separate elbow model demonstrated weaker predictive performance (RMSE: 21.3; R2: 0.42; calibration: 1.25 [1.16, 1.34]), as did a separate shoulder model (RMSE: 17.9; R2: 0.57; calibration: 1.01 [0.92, 1.10]).

Conclusions

The injury burden prediction model demonstrated excellent performance. Caution should be advised with predictions between one to 14 days lost to arm injury. Separate elbow and shoulder prediction models demonstrated decreased performance. The inclusion of both modifiable and non-modifiable factors into a comprehensive injury burden model provides the most accurate prediction of days lost in professional pitchers.

Level of Evidence

2.

Body composition variations between injured and non-injured professional soccer players

Professional soccer is characterized by its physical demands, making players' exposure to high injury risks a growing problem. It is crucial to study the factors associated with injuries in professional soccer. This study aimed to investigate the relationship between age, body composition, and others variables related with the injury profile of professional soccer players of a specific Portuguese team. Also, it analyzed the impact of the injury profile on soccer's variations in body fat (BF%), skeletal muscle mass (SMM) and total body water (TBW) throughout the season. The sample comprised 31 male professional soccer players competing in the First Portuguese Soccer League. Older players had a higher prevalence of muscular injuries. Midfielders and forwards showed the highest number of muscular injuries during the season being quadriceps the most affected zone. Considering players' BF% [Wilks' Lambda = 0.42, F (7, 23) = 4.61, p = 0.002, r = 0.58], SMM [Wilks' Lambda = 0.59, F (6, 23) = 2.70, p = 0.039, r = 0.41] and TBW [Wilks' Lambda = 0.54, F (7, 23) = 2.80, p = 0.029, r = 0.46] there was a substantial main effect for the assessments performed throughout the season and the injury status. Age assumes relevance in explaining the injury profile. The impact of the injury profile on soccer's variations in BF%, SMM and TBW throughout the season must be analyzed considering the clinical relevance.

Study on Hamstring Re-injury Prevention (SHARP): protocol for an international multicentre, randomised controlled trial

INTRODUCTION

Previous studies showed that the Nordic hamstring exercise (NHE) effectively prevents primary hamstring injury. However, no study investigated the secondary preventing effect of the NHE on hamstring reinjury. The primary purpose of this study is to investigate the effectiveness of the NHE for preventing hamstring reinjury after return to play (RTP) following a hamstring injury in football players. The secondary purpose is to determine the effect of the NHE on sprint and jump performance.

METHODS AND ANALYSIS

This is an international multicentre, prospective, parallel-group randomised controlled trial study. Subjects include male or female football players aged 18-40 years and within 1 week of RTP following a hamstring injury will be randomised into Nordics or a control group. Subjects in both groups continue their regular football training, but the Nordics group will perform an additional NHE programme. An online questionnaire will be sent to the subjects in both groups once per week within the first 10 weeks, then continued at months 6, 9 and 12. In a (performance) substudy, we will evaluate the effect of the NHE on sprint and vertical jump performance at three time points (at the beginning of the study, after 10 weeks and 12 months of follow-up).The primary outcomes are the incidence of hamstring reinjury within 2 and 12 months. The secondary outcomes are sprint and jump performance, adherence to the programme, duration of reinjury and reinjury burden.

ETHICS AND DISSEMINATION

This study is approved by the medical ethics committee of Amsterdam University Medical Center (UMC) in the Netherlands (METC 2021_117), Faculty of Medicine Universitas Gadjah Mada in Indonesia (KE/FK/1248/EC/2021), Norwegian School of Sport Sciences in Norway (number 216-2 70 122) and Denmark (ethical submission in process). The study's findings will be disseminated in scientific peer-reviewed journals and presented at international conferences.

TRIAL REGISTRATION NUMBER

NL9711.

Growth, maturation and injuries in high-level youth football (soccer): A mini review

Understanding the challenges football (soccer) players face during adolescence is fundamental to avoid disruptions in their development due to injury. This mini review will describe basic concepts of somatic growth and biological maturity, examine data from 53 prospective epidemiological studies on high-level youth football players and discuss how age, growth and maturity may affect the injury patterns observed. Based on the existing evidence, at least every third player sustains an injury during a football season. The thigh (median for studies of boys: 25%, median for girls: 21%), ankle (b: 18%, g: 30%), knee (b: 17%, g: 18%) and hip/groin (b: 14%, g: 10%) are the body parts injured most often, while muscle strains (b: 31%, g: 25%), sprains (b: 20%, g: 27%) and contusions (b: 17%, g: 16%) are the most common injury types. Injury trends are, however, not consistent throughout adolescence, and players' age, maturity status and position relative to peak height velocity (PHV) have shown to influence the number, type and location of injuries sustained. Despite a high volume of observational injury studies published on high-level youth players, girls (7 studies) and settings outside of Europe (included in 23% of studies) are underrepresented and should receive extra attention in the future. Based on the available epidemiological data, tailored injury reduction programmes can be considered in youth football, alongside application of general training principles such as progression, variation and individualization which may be especially important during vulnerable phases such as the adolescent growth spurt.