Matching the choice of injury/illness definition to study setting, purpose and design: one size does not fit all!

Training injuries in elite men's senior and academy (Super League) rugby league; an analysis of 224,000 exposure-hours

OBJECTIVES

Report two-years of training injury data in senior and academy professional rugby league.

DESIGN

Prospective cohort study.

METHODS

Match and training time-loss injuries and exposure data were recorded from two-seasons of the European Super League competition. Eleven/12 (2021) and 12/12 (2022) senior and 8/12 (2021) and 12/12 (2022) academy teams participated. Training injuries are described in detail and overall match injuries referred to for comparison only.

RESULTS

224,000 training exposure hours were recorded with 293 injuries at the senior (mean [95 % confidence interval]; 3 [2-3] per 1000 h) and 268 academy level (2 [2-3] per 1000 h), accounting for 31 % and 40 % of all injuries (i.e., matches and training). The severity of training injuries (senior: 35 [30-39], academy: 36 [30-42] days-lost) was similar to match injuries. Lower-limb injuries had the greatest injury incidence at both levels (senior: 1.85 [1.61-2.12], academy: 1.28 [1.08-1.51] per 1000 h). Head injuries at the academy level had greater severity (35 [25-45] vs. 18 [12-14] days-lost; p < 0.01) and burden (17 [16-18] vs. 4 [4-5] days-lost per 1000 h; p = 0.02) than senior level. At the senior level, the incidence of contact injuries was lower than non-contact injuries (risk ratio: 0.29 [0.09-0.88], p = 0.02).

CONCLUSIONS

Training injuries accounted for about a third of injuries, with similar injury severity to match-play. Within training there is a higher rate of non-contact vs. contact injuries. Whilst current injury prevention interventions target matches, these data highlight the importance of collecting high quality training injury data to develop and evaluate injury prevention strategies in training.

Ankle, knee and concussion concerns: Unveiling injury patterns in highly trained South African netball players

OBJECTIVES

To describe the rate and type of netball injuries sustained during women's university-level tournament matches in South Africa.

DESIGN

Descriptive epidemiological study.

SETTING

Three editions of the women's Varsity Netball tournament (2021-23).

PARTICIPANTS

Student-athletes representing nine university women's teams.

MAIN OUTCOME MEASURES

Medical attention match injuries prospectively recorded by team medical staff. Injuries were classified according to the 2020 consensus statement, with the addition of "concussion" as a separate pathology type. The main outcomes are reported as incidence (injuries per 1000h; 95% confidence intervals - CIs), burden (days lost per 1000h; 95%CIs), and frequency (% of all injuries).

RESULTS

Sixty-three injuries were recorded from 48 different players (58.8 per 1000h; 45.2-75.3) and the overall injury burden was 401 days per 1000h (364-440). Injury incidence by pathology type was highest for joint sprains (28.9 per 1000h), tendinopathies (7.5 per 1000h), and concussions (4.7 per 1000h). Joint sprains to the ankle accounted for 49% of the overall estimated days lost.

CONCLUSIONS

Ankle joint sprains should be the primary target of injury risk reduction programmes in highly trained netball players. Concussions were reported and efforts should be made to increase awareness among players, coaches and medical staff.

Foot and Ankle MRI Findings in Asymptomatic Professional Ballet Dancers

Background

Previous research in sport populations has demonstrated that abnormal magnetic resonance imaging (MRI) findings may be present in individuals without symptoms or known pathology. Extending this understanding to ballet, particularly in relation to the foot and ankle, is important to guide medical advice given to dancers.

Purpose

To assess foot and ankle MRI scans in asymptomatic ballet dancers focusing on bone marrow edema and the posterior ankle and to investigate whether these MRI findings would become symptomatic within 1 year.

Study Design

Case series; Level of evidence, 4.

Methods

In total, 31 healthy dancers (62 feet/ankles; 15 male and 16 female; age, 26.5 ± 4.3 years) who were dancing in full capacity were recruited from an elite professional ballet company. Orthogonal 3-plane short tau inversion recovery imaging of both feet and ankles was obtained using 3T MRI and the images were reviewed using a standardized evaluation form by 2 musculoskeletal radiologists. Injuries in the company were recorded and positive MRI findings were assessed for correlation with any injuries requiring medical attention during the subsequent 12 months.

Results

A total of 51 (82%) of the 62 feet and ankles had ≥1 area of bone marrow edema. The most common locations of bone marrow edema were the talus (n = 41; 66%), followed by first metatarsal (n = 14; 23%). Os trigonum and Stieda process were seen in 5 (8%) and 8 (13%) ankles, respectively. Among them, 2 os trigona showed bone marrow edema. Fluid in the anterior and posterior talocrural joints and the subtalar joint was observed in 48%, 63%, and 63% of these joints, respectively. Fluid around foot and ankle tendons was observed, with the most prevalent being the flexor hallucis longus tendon (n = 13; 21%). Two dancers who had positive findings on their MRI subsequently developed symptoms during the next 12 months.

Conclusion

Positive MRI findings are commonplace in the foot and ankle of asymptomatic professional ballet dancers. The majority do not result in the development of symptoms requiring medical attention within 12 months. Careful interpretation of MRI findings with the dancer's clinical picture is required before recommending activity modification or further intervention.

Injury Prevalence Among Elite Adolescent Ballet Dancers is not Affected by Frequency of Questionnaire Administration: A 6-Month Exploratory Prospective Study

INTRODUCTION

The Oslo Sports Trauma Research Centre Questionnaire on Health Problems (OSTRC-H) is a valid and reliable registration method for self-reported injuries and is regularly used among dancer populations. Monthly questionnaire administration is acceptable in athlete populations but has not been evaluated in dancers. The aim of this exploratory study was to assess the influence of weekly versus monthly administration of the OSTRC-H on estimated injury outcomes among elite adolescent ballet dancers.

METHODS

Participants (n = 103) were prospectively followed for 6 months and completed the OSTRC-H online, evaluating perceived consequences of self-reported health problems during the previous week and the previous 4 weeks, respectively. Four definitions of dance-related injury were utilized: (1) all complaints, (2) substantial, (3) medical attention, and (4) time-loss injuries. Descriptive statistics estimated: (1) the number of injuries reported (count), (2) average injury prevalence [proportion, 95% confidence intervals (CI)], (3) average severity score (0-100), and (4) days of time loss (count) for each injury definition. The 4 outcome measures were then compared between weekly and monthly registration with paired sample t-tests (P < .05) and overlapping 95% CI.

RESULTS

A significant difference between the number of all complaints injuries (weekly: 133; monthly: 94; P < .001) and substantial injuries (weekly: 64; monthly: 45; P = .012) was found. Regardless of injury definition, there were no significant differences between injury prevalence, severity scores, and days of time loss when reported weekly versus monthly.

CONCLUSION

Monthly administration of the OSTRC-H is an acceptable method to estimate injury prevalence, severity scores, and days of time loss amongst elite adolescent ballet dancers.

Injury Risk Analysis among Judo Athletes with Intellectual Disabilities

The main aim of this study was to evaluate injury prevalence, incidence rate, and burden in judo athletes with intellectual disabilities (ID) who participate in international competitions. This retrospective cross-sectional study analyzed data from the past year for 182 judo athletes with ID. Data was collected using a self-reported questionnaire, adapted from previous research, that included questions about injuries impacting training or competition, injury type, mechanism, severity, diagnosis, and location on the body. The injury prevalence among judo athletes with ID occurred most often during training (68.2%) and primarily affected the lower extremities (35%). Age group and injury prevalence were significantly related (χ2=7.91; P=0.04), while gender, weight, and ability level were not. Results were closer to those previously reported for conventional judo, which is likely due to the lower practice intensity among judo athletes with ID. Injury prevalence was lower than in prior studies, but the incidence rates aligned when considering training time in judo athletes with ID. Injury burden analysis revealed that females had a lower burden than males, while older athletes experienced a higher burden than younger athletes. Most injuries occur during training, which is likely attributable to safety-focused competition rules.

Female National Collegiate Athletic Association Division-I Athlete Injury Prediction by Vertical Countermovement Jump Force-Time Metrics

ABSTRACT

Merrigan, JJ, Stone, JD, Kraemer, WJ, Vatne, EA, Onate, J, and Hagen, JA. Female National Collegiate Athletic Association Division-I athlete injury prediction by vertical countermovement jump force-time metrics. J Strength Cond Res 38(4): 783-786, 2024-Vertical countermovement jump (CMJ) assessments on force plates have been purported to screen for musculoskeletal injury risk (MSKI) but with little scientific support. Thus, this study aimed to identify associations and noncontact lower-body injury predictability with CMJ force-time metrics in female athletes. The study entailed a retrospective analysis of routine injury and performance monitoring from 155 female National Collegiate Athletics Association Division I athletes. Noncontact lower-body injuries included in analysis were confirmed by medical staff, occurred during competition or training, resulted in time loss from training, and occurred within 3 months following CMJ testing (2 maximal effort, no arm swing, jumps on dual force plates). A total of 44 injuries occurred within 3 months following CMJ baseline testing and resulted in an average of 24.5 missed days from training. Those who sustained an injury were more likely to sustain another injury (15 of 44 injuries [33.1%]; odds ratio = 3.05 [95% CI = 1.31-6.99]). For every 1-unit increase from the mean in eccentric mean power and minimum eccentric force, there was a decrease in odds of sustaining a MSKI. Despite high overall model accuracy (85.6%), the receiving operating characteristic area under the curve (65.9%) was unacceptable and the true positive rate (recall) was 0.0%. Thus, no injuries in the testing data set were correctly classified by the logistic regression model with CMJ force-time metrics as predictors. Baseline CMJ assessment may not be useful for noncontact lower-body musculoskeletal injury screening or predictability in National Collegiate Athletics Association female athletes.

A Comprehensive Analysis of Injuries During Army Basic Military Training

INTRODUCTION

The injury definitions and surveillance methods commonly used in Army basic military training (BMT) research may underestimate the extent of injury. This study therefore aims to obtain a comprehensive understanding of injuries sustained during BMT by employing recording methods to capture all physical complaints.

MATERIALS AND METHODS

Six hundred and forty-six recruits were assessed over the 12-week Australian Army BMT course. Throughout BMT injury, data were recorded via (1) physiotherapy reports following recruit consultation, (2) a member of the research team (third party) present at physical training sessions, and (3) recruit daily self-reports.

RESULTS

Two hundred and thirty-five recruits had ≥1 incident injury recorded by physiotherapists, 365 recruits had ≥1 incident injury recorded by the third party, and 542 recruits reported ≥1 injury-related problems via the self-reported health questionnaire. Six hundred twenty-one, six hundred eighty-seven, and two thousand nine hundred sixty-four incident injuries were recorded from a total of 997 physiotherapy reports, 1,937 third-party reports, and 13,181 self-reported injury-related problems, respectively. The lower extremity was the most commonly injured general body region as indicated by all three recording methods. Overuse accounted for 79% and 76% of documented incident injuries from physiotherapists and the third party, respectively.

CONCLUSIONS

This study highlights that injury recording methods impact injury reporting during BMT. The present findings suggest that traditional injury surveillance methods, which rely on medical encounters, underestimate the injury profile during BMT. Considering accurate injury surveillance is fundamental in the sequence of injury prevention, implementing additional injury recording methods during BMT may thus improve injury surveillance and better inform training modifications and injury prevention programs.

Relationships between physical fitness characteristics, technical skill attributes, and sports injury in female Australian football players

OBJECTIVES

To explore the relationships between physical fitness and i) technical skills and ii) time-loss from Australian football injury in female players across the talent and participation pathways.

METHODS

This study uses a subset of data from two cross-sectional and one prospective cohort studies. A total of 223 female Australian football players across five competition levels (elite/non-elite senior, high-level junior, and non-elite junior (14-17 years)/(10-13 years)) were included in this study. Comprehensive physical fitness assessments and modified Australian football kicking and handballing tests were conducted in the 2018/19 pre-seasons. During the respective competitive in-season, time-loss injuries were recorded by team personnel. Stepwise multiple linear regressions were performed to determine the relationship between physical fitness and kicking and handballing scores. Cox proportional regressions were conducted to identify physical fitness factors associated with injury.

RESULTS

Increased running vertical jump height, greater hip abduction strength, and faster timed 6 m hop speed demonstrated a relationship with kicking accuracy when adjusted for years of Australian football playing experience (adjusted R2 = 0.522, p < 0.001). Faster agility time and increased lean mass were associated with better handballing accuracy (adjusted R2 = 0.221, p < 0.001). Multivariate Cox regression revealed an increased risk for sustaining a time-loss injury in less agile players (adjusted HR 2.41, 95% CI 1.23, 4.73, p = 0.010). However, this relationship no longer remained when adjusted for age and years of Australian football experience (adjusted HR 1.68, 95% CI 0.81, 3.50, p = 0.166).

CONCLUSIONS

Physical fitness may be a significant factor contributing to development of Australian football technical skills in female players. However, its role is unclear in protecting against injury risk in this athlete population. Further research is needed to explore the multifactorial and complex phenomenon of talent development and injury risk reduction in female Australian football players.

Umbrella review of musculoskeletal injury burden in dancers: implication for practice and research

BACKGROUND

Dancers are susceptible to injury. Nevertheless, injury epidemiology research in dancers is inconsistent. Furthermore, ballet dancing has dominated the huge body of reviews analyzing the epidemiology of musculoskeletal injuries in a variety of artistic dance forms, making it challenging to acquire a thorough, comprehensive, and understandable reporting of the available data.

PURPOSE

The overview and reanalysis of dancers' musculoskeletal pain and injury load across artistic dance forms.

STUDY DESIGN

Systematic review of systematic reviews and meta-analysis.

METHODS

A search was conducted online for literature written in English using PubMed and Google Scholar (2012-2021). The data gathered was then analyzed using predetermined qualifying criteria.

RESULTS

12 reviews were determined to be qualified, the majority of which had moderate to low confidence and raised concerns about bias based on JBI-URARI and ROBIS. The prevalence of dance-related musculoskeletal injuries ranged from 26% to 84% in any artistic dancers and 42% to 343% in ballet dancers. The incidence was less than 5 per 1000 dance hours in both groups, with lower extremities and back being the commonly reported sites. Reviews themselves stated that the quality of the reviews was often poor. Due to the study's heterogeneity and methodological inconsistency, data pooling and meta-analysis were not possible.

CONCLUSION

The current review emphasizes the gaps and restrictions in the dance epidemiology literature that make it challenging to quantify and report a single overall injury rate for dancers. These results underline the need for better primary investigations and evidence synthesis. As injury epidemiology is a critical component of the overall injury-prevention puzzle, there is a need for standardization in future research, particularly with active and prospective injury surveillance, injury classification, injury evaluation, and injury reporting.

LEVEL OF EVIDENCE

Systematic Review, Level III.

Injuries and Associated Factors in Swedish Sporting and Utility Trial Dogs-A Cross-Sectional Study

Canine sporting competitions, e.g., agility, obedience, rally obedience, and utility trials, e.g., protection, tracking, search, and messenger, are physically and mentally demanding disciplines. This study aimed to describe the types and frequencies of injuries experienced amongst Swedish sporting and utility trial dogs and to explore associations between discipline, breed, sex, neuter status, age, and injury history. Dog handlers provided information on competition-level dogs (n = 1582) through a cross-sectional survey. The overall proportion of dogs sustaining any injury during their lifetime, whether it was during competition, training, or outside of sport, was 58.7% (n = 928). Muscular, joint, and dermatologic injuries were most commonly reported and the most common injury locations were the thoracic, lumbar and lumbosacral spine, paw, head, shoulder, and stifle. According to multivariate analysis, Border Collie (adjusted OR 1.93), Belgian Malinois (adjusted OR 2.51) and higher age at the time of report (adjusted OR 1.81-9.67) increased the odds of injury history. Our results provide more understanding of injuries in sporting and utility dogs and contribute to injury prevention strategies that potentially enhance canine welfare.

Knee, Low Back, and Shoulder Problems Among University and Professional Volleyball Players: Playing With Pain

CONTEXT

The knee, low back, and shoulder account for most overuse injuries in volleyball. Previous researchers have used methodology that did not examine the extent of injury burden and effect on performance.

OBJECTIVE

To develop a more accurate and complete understanding regarding the weekly prevalence and burden of knee, low back, and shoulder problems within the highest levels of men's volleyball, including the role that preseason complaints, match participation, player position, team, and age have on complaints.

DESIGN

Descriptive epidemiology study.

SETTING

Professional volleyball clubs and the National Collegiate Athletic Association Division I program.

PATIENTS OR OTHER PARTICIPANTS

A total of 75 male volleyball players, representing 4 teams playing in their country's respective premier league (Japan, Qatar, Turkey, and the United States), participated over a 3-season period.

MAIN OUTCOME MEASURE(S)

Players completed a weekly questionnaire (Oslo Sports Trauma Research Centre Overuse Injury Questionnaire) reporting pain related to their sport and the extent to which knee, low back, and shoulder problems affected participation, training volume, and performance. Problems leading to moderate or severe reductions in training volume or performance or the inability to participate were considered substantial problems.

RESULTS

The mean weekly prevalence of knee, low back, and shoulder problems based on 102 player-seasons was 31% (95% CI = 28%, 34%), 21% (95% CI = 18%, 23%), and 19% (95% CI = 18%, 21%), respectively. Most players (93%, 95/102 player-seasons) reported some level of knee (79%, n = 81/102 player-seasons), low back (71%, n = 72/102 player-seasons), or shoulder (67%, n = 68/102 player-seasons) complaints during the season. Most players (58%, n = 59/102 player-seasons) experienced at least 1 episode of substantial problems affecting the knee (33%, n = 34/102 player-seasons), low back (27%, n = 28/102 player-seasons), or shoulder (27%, n = 28/102 player-seasons). Players with preseason complaints had more in-season complaints than teammates without preseason problems (mean weekly prevalence: knee, 42% versus 8%, t49 = -18.726, P < .001; low back, 34% versus 6%, t32 = -12.025, P < .001; shoulder, 38% versus 8%, t30 = -10.650, P < .001).

CONCLUSION

Nearly all included elite male volleyball players experienced knee, low back, or shoulder problems, and most had at least 1 bout that substantially reduced training participation or sport performance. These findings suggest that knee, low back, and shoulder problems result in greater injury burden than previously reported.

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.

#ReadyToPlay: health problems in women's football-a two-season prospective cohort study in the Norwegian premier league

OBJECTIVES

To describe the prevalence, incidence and burden of all health problems in the Norwegian women's premier league.

METHODS

During the 2020 and 2021 seasons, players in the Norwegian women's premier league reported all health problems (sudden-onset injuries, gradual-onset injuries and illnesses) weekly, using the Oslo Sports Trauma Research Centre Questionnaire on Health Problems. Team medical staff diagnosed reported problems using the Sport Medicine Diagnostic Coding System. We calculated average weekly prevalence, incidence and burden of all health problems reported.

RESULTS

We included 294 players (age: 22±4 years) from 11 teams. Response rate to the weekly questionnaire was 79%. On average, 32% (95% CI: 31% to 33%) of the players reported at least one health problem at any time and 22% (95% CI: 21% to 23%) reported a substantial health problem negatively affecting their training volume or performance. The overall incidence was 10.7 health problems per 1000 hours of football exposure. Sudden-onset injuries were most severe (68% of the total time loss), followed by gradual-onset injuries (25%) and illnesses (8%). Thigh was the most common injury location (26%), while knee injuries were most severe, causing 42% of the total injury time loss. Anterior cruciate ligament (ACL) injuries alone caused 30% of the total injury time loss.

CONCLUSION

One in five players had a health problem negatively affecting their training volume or performance at any time. Sudden-onset injuries represented the most burdensome health problem. Thigh injuries were most frequent, while knee injuries, ACL injuries especially, were most severe.

Musculoskeletal Complaint Epidemiology in Australian Special Operation Forces Trainees

INTRODUCTION

Elite military trainees are burdened by high numbers of musculoskeletal (MSK) injuries and are a priority military population for injury prevention. This research aims to describe the MSK complaint epidemiology of trainees undertaking special forces (SF) training in the Australian Defence Force (ADF). One barrier to accurate injury surveillance in military populations is that traditional surveillance methods rely on personnel engaging with the military healthcare system to collect injury data. This approach is likely to underestimate the injury burden as it is known that many military personnel, particularly trainees, avoid reporting their injuries because of various motives. Subsequently, the insights from surveillance systems may underestimate the injury burden and limit the ability to inform prevention requirements. This research aims to actively seek MSK complaint information directly from trainees in a sensitive manner to mediate injury-reporting behaviors.

MATERIALS AND METHODS

This descriptive epidemiology study included two consecutive cohorts of ADF SF trainees from 2019 to 2021. Musculoskeletal data items and their respective recording methods were based on international sports injury surveillance guidelines and adapted to a military context. Our case definition encompassed all injuries or physical discomforts as recordable cases. A unit-embedded physiotherapist retrospectively collected MSK complaint data from selection courses and collected prospective data over the training continuum. Data collection processes were external to the military health care system to mediate reporting avoidance and encourage injury reporting. Injury proportions, complaint incidence rates, and incidence rate ratios were calculated and compared between training courses and cohorts.

RESULTS

In total, 334 MSK complaints were reported by 103 trainees (90.4%), with a complaint incidence rate of 58.9 per 1,000 training weeks (95% CI, 53.0-65.5). Of these MSK complaints, 6.4% (n = 22) resulted in time loss from work. The lumbar spine (20.6%, n = 71) and the knee (18.9%, n = 65) were the most frequently affected body parts. Most of the MSK complaints were reported during selection courses (41.9%), followed by field survival and team tactics (23.0%) and urban operations courses (21.9%). Physical training accounted for 16.5% of complaints. Fast-roping training was associated with more severe MSK complaints.

CONCLUSIONS

Musculoskeletal complaints are highly prevalent in ADF SF trainees. Complaints are more frequently reported in selection and qualification training courses than in physical training. These activities are priorities for focused research to understand injury circumstances in ADF elite training programs to inform injury prevention strategies. A strength of our study is the data collection methods which have provided greater MSK complaint information than past research; however, much work remains in conducting consistent and accurate surveillance. Another strength is the use of an embedded physiotherapist to overcome injury-reporting avoidance. Embedded health professionals are recommended as continued practice for ongoing surveillance and early intervention.

Musculoskeletal Injury in an Australian Professional Ballet Company, 2018-2021: 953 Medical-Attention and 706 Time-Loss Injuries Over 4 Years

OBJECTIVES: To describe the incidence rate, frequency, severity, recurrence, and burden of musculoskeletal injury in professional ballet. STUDY DESIGN: Descriptive epidemiological (retrospective). METHODS: Professional dancers (n = 73, 40 females, 33 males) provided consent for retrospective review of musculoskeletal injury data. Medical-attention injuries were reported to and recorded by onsite physiotherapists between January 2018 and December 2021. Time-loss injuries were any injury that prevented a dancer from taking a full part in all dance-related activities for >1 day. Injuries were classified using the OSICS-10.1 system. Injury incidence rates (IIRs; injuries/1000 h), severity, recurrence, and burden were calculated. RESULTS: Nine hundred and fifty-three medical-attention injuries were recorded in 72 (98%) dancers at an IIR of 2.79/1000 h (95% confidence interval [CI], 2.62-2.98). 706 were time-loss injuries, which were reported in 70 dancers at an IIR of 2.07/1000 h (95% CI: 1.92, 2.23). Overuse injuries represented 53% of medical-attention injuries. The most frequently injured body area and tissue/pathology were thoracic facet joint (n = 63/953, 7%) and ankle synovitis/impingement (n = 62/953, 6%). Bone stress injuries (BSIs) were the most severe with the highest median time loss (135 days, interquartile range [IQR] 181) followed by fractures (72.5 days, IQR 132). The injuries with the highest burden were tibial BSIs (13 days lost/1000 h; 95% CI: 13, 14). Jumping and lifting were the most frequently reported injury mechanisms. CONCLUSION: Almost all dancers required medical attention for at least one injury during the surveillance period. Approximately 74% of injuries resulted in time loss. BSIs and ankle synovitis/impingement were of high burden, and a high proportion of BSIs were recurrent. J Orthop Sports Phys Ther 2023;53(11):712-722. Epub 14 September 2023. doi:10.2519/jospt.2023.11858.

Injury data collection and utilisation practices in university sports teams: A cross-sectional study

OBJECTIVES

This study aimed to examine injury surveillance practices in a variety of university sports teams and barriers and facilitators for injury data collection and utilisation.

DESIGN

Cross-sectional study.

SETTING

University sports teams in Japan.

PARTICIPANTS

Medical, coaching, and other staff (non-medical/-coaching staff) of the university sports teams in Japan.

MAIN OUTCOME MEASURES

The survey included 31 questions that examined the barriers and facilitators for injury data collection, and the type of data on injury and exposure collected.

RESULTS

Injury data were collected during matches for 69 teams (48.3%) and training for 61 teams (42.7%). Injuries were primarily captured by athletic trainers in teams with medical staff, coaching staff and athletes in teams without medical staff. Common barriers in collecting and utilising injury data included limited funding for trained personnel and lack of time for medical staff to record data. Facilitating factors included clarification of the methods employed in recording and utilising injury data for teams with medical staff and the deployment of trained personnel to record injuries for teams without medical staff.

CONCLUSIONS

Approximately half of the Japanese university teams collected injury data. Considering barriers and facilitators is crucial to facilitate the collection and utilisation of injury data.

Dance-related musculoskeletal injury leading to forced time-loss in elite pre professional dancers - a retrospective study

OBJECTIVES

Describe the epidemiology of dance-related musculoskeletal injury leading to forced time-loss in elite pre-professional dancers and provide descriptive data on the prevalence concerning diagnoses, location, and injury type, stratified by gender and skill level.

METHODS

Retrospective cohort, over a 3-year period on a full-time pre-professional Portuguese dance school featuring 70 both gender students with a mean age of 14.87 years. A total of 110 injuries were analyzed. Non-parametric statistics were used.

RESULTS

The most prevalent diagnosis leading to forced time-loss in female dancers were Medial Tibial Stress Syndrome (MTSS), 14.29%, and Posterior Ankle Impingement Syndrome (PAIS), 7.14%, whereas in male dancers these were Hallux Sprain, 17.50%, and Lumbar Spine Joint Injuries, 7.50%. Differences were found in injuries' anatomical location between genders and in Incidence Proportion and Clinical Incidence between skill levels. 72.20% of the chronic injuries and 50.00% of the acute injuries occurred in Level III students.

CONCLUSIONS

With respect to forced time-loss injuries, male dancers were found to sustain more acute traumatic injuries and female dancers overuse, respectively, sprains and MTSS and PAIS. Identifying which injuries are most likely to lead to forced time-loss may be useful for helping health-care professionals in clinical decision-making and in developing more effective injury prevention and management strategies.

Methods of Monitoring Internal and External Loads and Their Relationships with Physical Qualities, Injury, or Illness in Adolescent Athletes: A Systematic Review and Best-Evidence Synthesis

BACKGROUND

With the increasing professionalisation of youth sports, training load monitoring is increasingly common in adolescent athletes. However, the research examining the relationship between training load and changes in physical qualities, injury, or illness in adolescent athletes is yet to be synthesised in a systematic review.

OBJECTIVE

The aim of this review was to systematically examine the research assessing internal and external methods of monitoring training load and physical qualities, injury, or illness in adolescent athletes.

METHODS

Systematic searches of SPORTDiscus, Web of Science, CINAHL and SCOPUS were undertaken from the earliest possible records to March 2022. Search terms included synonyms relevant to adolescents, athletes, physical qualities, injury, or illness. To be eligible for inclusion, articles were required to (1) be original research articles; (2) be published in a peer-reviewed journal; (3) include participants aged between 10 and 19 years and participating in competitive sport; (4) report a statistical relationship between a measure of internal and/or external load and physical qualities, injury or illness. Articles were screened and assessed for methodological quality. A best-evidence synthesis was conducted to identify trends in the relationships reported.

RESULTS

The electronic search yielded 4125 articles. Following screening and a review of references, 59 articles were included. The most commonly reported load monitoring tools were session ratings of perceived exertion (n = 29) and training duration (n = 22). Results of the best-evidence synthesis identified moderate evidence of positive relationships between resistance training volume load and improvement in strength, and between throw count and injury. However, evidence for other relationships between training load and change in physical qualities, injury, or illness were limited or inconsistent.

CONCLUSIONS

Practitioners should consider monitoring resistance training volume load for strength training. Additionally, where appropriate, monitoring throw counts may be useful in identifying injury risk. However, given the lack of clear relationships between singular measures of training load with physical qualities, injury, or illness, researchers should consider multivariate methods of analysing training load, as well as factors that may mediate the load-response relationship, such as maturation.

Injuries and Overuse Syndromes in Rink Hockey Players

Rink Hockey is a high-speed low-contact sport with a widely recognized injury potential. Played with a hard ball by players wearing little or no protective gear, the rates of concussions and head injuries are of high interest. In this study, we reviewed and investigated injuries sustained by 108 German National League rink hockey players. We conducted an epidemiological cross-sectional study to determine sport-specific injuries and injury patterns in female and male rink hockey players. Data were collected by a standardized questionnaire. A total of 108 players participated in the study. The combined rate of injuries were 9.4/1000 athlete exposures. There was no significant difference between injury rates during games and practice. A sexspecific difference was not detected. Head injuries were the most frequent type (20.8 % of all injuries). Concussions made up 7 % of all head injuries with a rate of 0.76/1000 athlete exposure. Ball contact was the cause for 31 % of injuries, while player contact generated 26.2 % of all injuries. High rates of ball-contact-related injuries resulted in time loss and medical consultations. Head injuries were frequent, however did not result in significant time loss as compared to other injuries. The use of protective gear should be recommended.

Irish Dancing Injuries and Associated Risk Factors: A Systematic Review

Irish dance is growing in popularity, evolving to a more athletic and demanding dance style. The aim of this study is to conduct a systematic review, previously registered with PROSPERO, to identify the prevalence, incidence, and the injury pattern among Irish dancers and analyse the associated risk factors. Six online databases and two dance-specific science publications were searched systematically. Studies were included if the patterns of injuries among Irish dancers were evaluated or the factors associated with injury were analysed, published in English or Portuguese, in peer-reviewed scientific journals. Four reviewers assessed the quality and level of evidence using the Downs and Black criteria and a modified Oxford Centre of Evidence-Based Medicine 2009 model, respectively. Eleven articles were included, eight of Level 3c (cross-sectional) and three of Level 3b (prospective). Mean DB percentage score was 63% ± 7.2%. Prevalence ranged from 72.2% to 92.6%, affecting mostly the foot/ankle complex. Only two articles reported incidence, which ranged from 3.4 to 10.6 injuries/1000 h danced depending on injury definition. Psychological factors, elite level, and insufficient/poor sleep were associated with musculoskeletal injury. Injury prevalence and incidence is high in Irish dancers, with the foot and ankle being more affected. Due to heterogeneity in injury definitions, methods, and populations, along with the need for improvement in studies quality, recommendations were made for future research.

A systematic literature review of injury epidemiology and surveillance practices in elite adult female field-based team sport

OBJECTIVES

To describe injury incidence and surveillance practices in elite adult female field-based team sports.

DESIGN

Systematic literature review.

METHODS

This review was prospectively registered (PROSPERO CRD42022318642). CINAHL, PubMed, MEDLINE, Scopus, SPORTDiscus, Web of Science, Open Grey and Google Scholar were searched from inception to 30th June inclusive. Peer reviewed original research articles that reported the incidence of injury sustained by females aged ≥18 years in elite field-based team sports were included. The Newcastle Ottawa Scale was used to assess the risk of bias.

RESULTS

Twenty prospective cohort studies investigating injury incidence in Australian football, American football, soccer, field hockey, rugby, rugby-7s and cricket were eligible. A higher injury incidence in match play compared to training was reported with the highest match and training incidence (132.7 and 42.1/1000 h of exposure respectively) in Australian football. The majority of the reported injuries were to the lower limb and involved muscle/tendon or joint/ligaments. There was heterogeneity in definitions of injury, severity and exposure, variations in methods of injury data collection and reporting with, not all data being collected/reported optimally, which limited comparison of studies.

CONCLUSIONS

This review highlights the lack of and need for injury data specific to this cohort. Establishing the incidence of injury with a robust injury surveillance system is the first step in the sequence of injury prevention. It requires consistency in definitions and methodologies, providing accurate and useful injury data, to guide targeted injury prevention strategies.

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.

Injury epidemiology in Chinese undergraduate classical dance students: A 14-week prospective study

OBJECTIVES

The aim of this study was to investigate the injury prevalence, incidence rate, injury proportions, and characteristics of injuries in Chinese undergraduate classical dance students by using the modified Oslo Sports Trauma Research Centre Questionnaire on Health Problems.

DESIGN

Prospective study.

SETTING

Online survey.

PARTICIPANTS

63 Chinese classical undergraduate students (female: 40, male: 23; median age: 20 years, range: 17-20 years) completed the survey.

MAIN OUTCOME MEASURES

The injury prevalence (proportions) and incidence rate were calculated. The characteristics (severity, locations, injury type) of injuries were investigated.

RESULTS

During the 14-weeks, 84% students reported injury occurrence more than one time. The injury incidence rate was 3.28 injuries per 1000h across 14-weeks. Weekly proportion for all injuries ranged from 38.2% to 61.9% and substantial injuries ranged from 7.5% to 22.7%. The lower back was the most frequently injured body location (38.9%), followed by the knee (17.3%) and the ankle (12.9%). In all reported injuries, overuse injury was the most prevalent type (78.9%, 95% CI: 73.2%-81.1%).

CONCLUSIONS

Chinese classical dance students are at a relatively high risk for injuries. Injury prevention programs in Chinese classical dance students should focus on the lower back and lower extremity.

Epidemiology of Injuries during Judo Tournaments

Objective

To determine the injury incidence proportion, distribution of injuries by anatomical location; injury type; injury severity, time loss; mechanism and situations of injuries; and the relative risk of injuries by gender, age, and weight categories during judo tournaments. Study Design. It is a systematic review. Data Sources. A systematic review of the literature was conducted via searches in PubMed, EMBASE, Web of Science, CINAHL, SPORTDiscus, Google Scholar, and PEDro. Eligibility Criteria. All original studies on the incidence of injuries during judo tournaments were included.

Results

Twenty-five studies were included out of the 1979 studies. Using the modified AXIS tool score for quality assessment, seven were rated as having good quality, nine were rated as having fair quality, and four were rated as having poor quality. The injury incidence proportion during tournaments ranged from 2.5% to 72.5% for injuries requiring medical evaluation and 1.1% to 4.1% for injuries causing time loss (i.e., inability to continue game participation). The most commonly reported injury location was the head, followed by the hand, knee, elbow, and shoulder. The most frequent types of injury were sprains, followed by contusions, skin lacerations, strains, and fractures. In judo tournaments, injuries were more often sustained during standing fights (tachi-waza) than in ground fights (ne-waza).

Conclusion

The tournament injury incidence proportion ranged from 2.5% to 72.5% for injuries requiring medical attention and 1.1% to 4.1% for injuries causing time loss. The head was the most frequently injured body part, and sprain was the most frequent injury type. However, current reports on injuries during judo tournaments are heterogeneous and inconsistent, limiting our understanding of in-match injury risks. Future studies should utilize the guidelines of the International Olympic Committee consensus meeting statement on the methodological approach to injury reporting. We recommend a judo-specific extension of this statement to fit the unique features of judo sports practice.

Epidemiological Characteristics of Foot and Ankle Injuries in 2 Professional Ballet Companies: A 3-Season Cohort Study of 588 Medical Attention Injuries and 255 Time-Loss Injuries

Background

The foot and ankle are often reported as the most common sites of injury in professional ballet dancers; however, epidemiological research focusing on foot and ankle injuries in isolation and investigating specific diagnoses is limited.

Purpose

To investigate the incidence rate, severity, burden, and mechanisms of foot and ankle injuries that (1) required visiting a medical team (medical attention foot and ankle injuries; MA-FAIs) and (2) prevented a dancer from fully participating in all dance-related activities for at least 24 hours after the injury (time-loss foot and ankle injuries; TL-FAIs) in 2 professional ballet companies.

Study Design

Descriptive epidemiological study.

Methods

Foot and ankle injury data across 3 seasons (2016-2017 to 2018-2019) were extracted from the medical databases of 2 professional ballet companies. Injury-incidence rate (per dancer-season), severity, and burden were calculated and reported with reference to the mechanism of injury.

Results

A total of 588 MA-FAIs and 255 TL-FAIs were observed across 455 dancer-seasons. The incidence rates of MA-FAIs and TL-FAIs were significantly higher in women (1.20 MA-FAIs and 0.55 TL-FAIs per dancer-season) than in men (0.83 MA-FAIs and 0.35 TL-FAIs per dancer-season) (MA-FAIs, P = .002; TL-FAIs, P = .008). The highest incidence rates for any specific injury pathology were ankle impingement syndrome and synovitis for MA-FAIs (women 0.27 and men 0.25 MA-FAIs per dancer-season) and ankle sprain for TL-FAIs (women 0.15 and men 0.08 TL-FAIs per dancer-season). Pointe work and jumping actions in women and jumping actions in men were the most common mechanisms of injury. The primary mechanism of injury of ankle sprains was jumping activities, but the primary mechanisms of ankle synovitis and impingement in women were related to dancing en pointe.

Conclusion

The results of this study highlight the importance of further investigation of injury prevention strategies targeting pointe work and jumping actions in ballet dancers. Further research for injury prevention and rehabilitation strategies targeting posterior ankle impingement syndromes and ankle sprains are warranted.

A Validated Injury Surveillance and Monitoring Tool for Fast Jet Aircrew: Translating Sports Medicine Paradigms to a Military Population

Background

Military populations, including fast jet aircrew (FJA - aka fighter aircrew/pilots), commonly suffer from musculoskeletal complaints, which reduce performance and operational capability. Valid surveillance tools and agreed recordable injury definitions are lacking. Our objective was to develop and then evaluate the validity of a musculoskeletal complaints surveillance and monitoring tool for FJA.

Methods

A Delphi study with international experts sought consensus on recordable injury definitions and important content for use in a surveillance and monitoring tool for FJA. Using these results and feedback from end-users (FJA), the University of Canberra Fast Jet Aircrew Musculoskeletal Questionnaire (UC-FJAMQ) was developed. Following its use with 306 Royal Australian Air Force (RAAF) FJA over 4 × five-month reporting periods, validity of the UC-FJAMQ was evaluated via multi-level factor analysis (MFA) and compared with routine methods of injury surveillance.

Results

Consensus was achieved for: eight words/descriptors for defining a musculoskeletal complaint; six definitions of recordable injury; and 14 domains important for determining overall severity. The UC-FJAMQ was developed and refined. MFA identified three distinct dimensions within the 11 items used to determine severity: operational capability, symptoms, and care-seeking. MFA further highlighted that symptom severity and seeking medical attention were poor indicators of the impact musculoskeletal complaints have upon operational capability. One hundred and fifty-two episodes of time loss were identified, with the UC-FJAMQ identifying 79% of these, while routine methods identified 49%. Despite modest weekly reporting rates (61%), the UC-FJAMQ outperformed routine surveillance methods.

Conclusions

The UC-FJAMQ was developed to specifically address the complexities of injury surveillance with FJA, which are similar to those noted in other military and sporting populations. The results demonstrated the UC-FJAMQ to be sensitive and valid within a large group of FJA over 4 × five-month reporting periods. Adoption of consistent, sensitive, and valid surveillance methods will strengthen the FJA injury prevention literature, ultimately enhancing their health, performance, and operational capability.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40798-022-00484-1.

Cross-cultural adaptation and validation of the Kerlan-Jobe Orthopaedic Clinic shoulder and elbow score in Finnish-speaking overhead athletes

Background

The Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow score (KJOC) is developed to evaluate the shoulder and elbow function in overhead athletes. To date, the score has not been adapted into Finnish language. The aim of this study was to perform a cross-cultural adaptation of the Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow score (KJOC) into Finnish language and evaluate its validity, reliability, and responsiveness in overhead athletes.

Methods

Forward–backward translation method was followed in the cross-cultural adaptation process. Subsequently, 114 overhead athletes (52 males, 62 females, mean age 18.1 ± 2.8 years) completed the Finnish version of KJOC score, Disabilities of the Arm, Shoulder and Hand (DASH), American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) and RAND-36 to assess validity of the KJOC score. To evaluate reliability and responsiveness, the participants filled in the KJOC score 16 days and eight months after the first data collection. Validity, reliability, and responsiveness of the Finnish KJOC score were statistically tested.

Results

Minor modifications were made during the cross-cultural translation and adaptation process, which were related to culture specific terminology in sports and agreed by an expert committee. Construct validity of the KJOC score was moderate to high, based on the correlations with DASH (r = − 0.757); DASH sports module (r = − 0.667); ASES (r = 0.559); and RAND-36 (r = 0.397) questionnaires. Finnish KJOC score showed excellent internal consistency (α = 0.92) and good test–retest reliability (2-way mixed-effects model ICC = 0.77) with acceptable measurement error level (SEM 5.5; MDC 15.1). Ceiling effect was detected for asymptomatic athletes in each item (23.2–61.1%), and for symptomatic athletes in item 5 (47.4%). Responsiveness of the Finnish KJOC score could not be confirmed due to conflicting follow-up results.

Conclusion

The Finnish KJOC score was found to be a valid and reliable questionnaire measuring the self-reported upper arm status in Finnish-speaking overhead athletes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13102-022-00581-4.

Injury characteristics in Norwegian male professional football: A comparison between a regular season and a season in the pandemic

The Coronavirus Disease-19 (COVID-19) pandemic forced the Norwegian male premier league football season to reschedule, reducing the fixture calendar substantially. Previous research has shown that a congested match schedule can affect injury rates in professional football. Therefore, we aimed to investigate whether the Norwegian premier league teams suffered more injuries in the more match congested 2020 season than in the regular 2019-season. We invited all teams having participated in both seasons to export their injury data. Only teams that used the same medical staff to register injuries in both seasons were included, and to maximize data comparability between seasons, we applied a time-loss injury definition only. Seven of 13 teams agreed to participate and exported their injury data. Both seasons had 30 game weeks, but the 2020 season was 57 days shorter than the 2019 season. The match injury incidence did not differ significantly [incidence rate ratio 0.76 (0.48-1.20; p = 0.24) in the 2020 season compared to the 2019 season. Furthermore, we found no differences in the number of injuries, days lost to injury, matches missed to injury, or injury severity. We could not detect any differences between the two seasons, suggesting the congested match calendar combined with the safety measures in the 2020 season can be a safe alternative in future seasons.

Contribution of sex, sports and activity types and curriculum load distribution to intracurricular injury risk in physical education teacher education: a cohort study

Objectives

To investigate the influence of sports/activity types and their distribution over the curriculum years on intracurricular injury risk differences between curriculum years and sexes in Physical Education Teacher Education (PETE) studies.

Methods

In a cohort study over 14 years (2000-2014), injuries reported at the medical facility of a Dutch vocational institute by PETE students who completed their full curriculum were registered. Intracurricular injury rates (IR) per 1000 hours and 95% CIs were calculated per sport, sex and curriculum year and compared with injury rate ratios (RR) and 95% CI. Exposure times per sports category per curriculum year were compared with the χ2 test.

Results

Intracurricular IR was highest for gymnastics, team ball sports and track and field (0.76-1.23, 95% CI 0.65 to 1.45). IRs were higher for female compared with male students (RR 2.38, 95% CI 1.97 to 2.87). Comparisons for all individual sports and for all three curriculum years showed the same pattern. IR for the first year was higher than for the second (RR 1.79, 95% CI 1.45 to 2.21) and third year (RR 2.74, 95% CI 2.13 to 3.54) with similar patterns for all sports categories. Over the curriculum years, exposure time distributions per sport showed small differences (p<0.001, Cramer's V=0.07).

Conclusion

Curriculum year, sex and sports types are risk factors to be independently targeted for preventive and rehabilitative measures in PETE studies. The nature and aetiology of injuries in mixed sports, and the adaption to increased loads in first-year and female PETE students, need further investigation.

Data Collection Procedures and Injury Definitions in Badminton: A Consensus Statement According to the Delphi Approach

ABSTRACT

Previous studies involving injury surveillance in badminton players have used nonstandardized injury definitions and data collection methodologies. The purpose of this study was to apply a Delphi method to (1) reach a consensus on an injury definition in badminton and (2) develop a standardized badminton injury report form. An Injury Consensus Group was established under the auspices of the Badminton World Federation, and initial injury definitions and injury report form were developed. An internal panel was formed from the Injury Consensus Group, and an external panel was selected based on a combination of profession, experience in the field, sport-specific knowledge/expertise, and geographical location to obtain a widely representative sample. Through 2 rounds of voting by the external panel, consensus was reached on both the definition of an injury in badminton and a standardized injury report form. The agreed injury definition was "Any physical injury sustained by a player during a match or training regardless if further diagnostic tests were done or if playing time was lost" and the injury report form contained the following 7 sections: Injury record, Diagnosis, Injury mechanism, Regarding pain, Pain and return to play/training after injury, Grade of severity, and Recurrence. We recommend the use of the definitions and methods presented in this consensus statement for the reporting of injury in all international and domestic badminton players. This should make future injury surveillance reports directly comparable and hence more informative in recognizing trends over time and differences between countries.

Part 2 of the 11+ as an effective home-based exercise programme in elite academy football (soccer) players: a one-club matched-paired randomised controlled trial

Background:Although the 11+ is known to reduce injuries and improve performance in adolescent footballers, its duration presents a notable barrier to implementation. Hence, this study investigated injury and performance outcomes when 65 elite male academy footballers either performed Part 2 3x/week at training (TG) or at home (HG).Methods:Time to stabilisation (TTS), eccentric hamstring strength (EH-S) and countermovement jump height (CMJ-H) were collected 4 times during the 2019 football season. Linear mixed models were used to evaluate main and interaction effects of group and time. Bonferroni post-hoc tests were used to account for multiple comparisons. Differences in time loss and medical attention injuries were determined using a two-tailed Z test for a comparison of rates.Results:Relative to baseline, EH-S (HG 4.3 kg, 95% CI 3 to 5.7, p < 0.001; TG 5.5 kg, 95% CI 4.3 to 6.6, p < 0.001) and CMJ-H (HG 3.5 cm, 95% CI 2.2 to 4.7, p < 0.001; TG 3.2 cm, 95% CI 2.2 to 4.3, p < 0.001) increased, with no difference between groups observed at the end of the season. All injury outcomes were similar.Conclusion: Rescheduling Part 2 did not affect performance or increased injury risks in academy footballers.

Improving musculoskeletal injury surveillance methods in Special Operation Forces: A Delphi consensus study

Musculoskeletal injury mitigation is a priority in military organisations to protect personnel health and sustain a capable workforce. Despite efforts to prevent injury, inconsistencies exist in the evidence used to support these activities. There are many known limitations in the injury surveillance data reported in previous Special Operation Forces (SOF) research. Such studies often lack accurate, reliable, and complete data to inform and evaluate injury prevention activities. This research aimed to achieve expert consensus on injury surveillance methods in SOF to enhance the quality of data that could be used to inform injury prevention in this population. A Delphi study was conducted with various military injury surveillance stakeholders to seek agreement on improving surveillance methods in SOF. Iterative questionnaires using close and open-ended questions were used to collect views about surveillance methods related to injury case definitions and identifying essential and optional data requirements. Consensus was predefined as 75% group agreement on an item. Sixteen participants completed two rounds of questionnaires required. Consensus was achieved for 17.9% (n = 7) of questions in the first-round and 77.5% (n = 38) of round two questions. Several challenges for surveillance were identified, including recording injury causation, SOF personnel's injury reporting behaviours influencing accurate data collection, and surveillance system infrastructure limitations. Key military injury surveillance stakeholders support the need for improved data collection to enhance the evidence that underpins injury prevention efforts. The consensus process has resulted in preliminary recommendations to support future SOF injury surveillance.

Epidemiology of injuries sustained in professional Australian netball: A three season cohort study

OBJECTIVES

To report the medical attention and time-loss injury epidemiology of Australia's premier netball competition.

DESIGN

Descriptive epidemiological study.

METHODS

One-hundred and nineteen players in the Suncorp Super Netball league were under surveillance during three consecutive seasons (2017-2019), inclusive of pre-, in-, and post- season phases. Medical attention injuries were recorded by medical personnel, and additionally sub-categorised according to time loss. Injury incidence rates (IIR) and injury burden were calculated per 365 player contract days, with differences between season and season phase IIRs compared using negative binomial generated incidence rate ratios (IRR).

RESULTS

Eight hundred and sixty-six medical attention injuries and 393 time-loss injuries were recorded. The majority of the players had multiple (≥2) medical attention (n = 92; 77.3%) and time-loss (n = 75, 63.0%) injuries reported. The ankle (n = 181; 20.9%), knee (n = 136; 15.7%) and foot (n = 98; 11.3%) were the body sites with the most frequently reported medical attention injuries. Overall, there was a comparable injury incidence rate between the pre-season and in-season periods (IRR = 1.13, 95%CI = 0.98-1.30, p = 0.0842), although variation in the injury burden was identified. Ankle tendon injuries (23.5 days absence) and knee joint injuries (44.9 days absence) the most burdensome injuries in the pre-season and in-season periods respectively.

CONCLUSIONS

Lower limb injuries are the most frequent in professional level netball. Knee and ankle injuries are the most burdensome overall, however the type of injuries with a high burden vary between pre- and in-season periods. Time-loss, non-time loss and subsequent injuries are prominent in professional level netball.

Psychosocial Risk Factors for Overuse Injuries in Competitive Athletes: A Mixed-Studies Systematic Review

Background

While the psychosocial risk factors for traumatic injuries have been comprehensively investigated, less is known about psychosocial factors predisposing athletes to overuse injuries.

Objective

The aim of this review was to systematically identify studies and synthesise data that examined psychosocial risk factors for overuse injuries in athletes.

Design

Systematic review.

Data Sources

MEDLINE, Web of Science and PsycINFO databases, supplemented by hand searching of journals and reference lists.

Eligibility Criteria for Selecting Studies

Quantitative and qualitative studies involving competitive athletes, published prior to July 2021, and reporting the relationship between psychosocial variables and overuse injury as an outcome were reviewed. This was limited to academic peer-reviewed journals in Swedish, English, German, Spanish and French. An assessment of the risk of bias was performed using modified versions of the RoBANS and SBU Quality Assessment Scale for Qualitative Studies.

Results

Nine quantitative and five qualitative studies evaluating 1061 athletes and 27 psychosocial factors were included for review. Intra-personal factors, inter-personal factors and sociocultural factors were found to be related to the risk of overuse injury when synthesised and reported according to a narrative synthesis approach. Importantly, these psychosocial factors, and the potential mechanisms describing how they might contribute to overuse injury development, appeared to be different compared with those already known for traumatic injuries.

Conclusions

There is preliminary evidence that overuse injuries are likely to partially result from complex interactions between psychosocial factors. Coaches and supporting staff are encouraged to acknowledge the similarities and differences between traumatic and overuse injury aetiology.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-021-01597-5.

Dance Exposure, Individual Characteristics, and Injury Risk over Five Seasons in a Professional Ballet Company

PURPOSE

This study aimed to describe the relationships between dance exposure, dancer characteristics, and injury risk across five seasons in a professional ballet company.

METHODS

Dance exposure time and clinician-reported time-loss and medical attention injury data were prospectively collected from 118 professional dancers of The Royal Ballet between 2015/2016 and 2019/2020. Cox proportional hazards and shared frailty models were fitted to overuse and traumatic injuries; individualized robust Z-scores for 7- and 28-d accumulated exposure, and week-to-week change in exposure, age, sex, company rank, and injury history were included as time-varying covariates.

RESULTS

Across 381,710 h of exposure, 1332 medical attention and 427 time-loss injuries were observed. Positive relationships were observed between week-to-week change in exposure and overuse time-loss (+1 Z-score hazard ratio (HR), 1.27; 95% confidence interval (CI), 1.06-1.53) and medical attention injury risk (+1 Z-score HR, 1.17; 95% CI, 1.06-1.28). A negative relationship was observed between 7-d accumulated exposure and overuse medical attention injury risk (+1 Z-score HR, 0.74; 95% CI, 0.66-0.84). Overuse time-loss injury risk was greater in soloists compared with the corps de ballet (HR, 1.47; 95% CI, 1.01-2.15) and in dancers with a higher previous injury rate (+1 injury per 1000 h HR, 1.06; 95% CI, 1.02-1.10). Only age was associated with traumatic time-loss (+1-yr HR, 1.05; 95% CI, 1.01-1.09) or medical attention injury risk (+1-yr HR, 1.04; 95% CI, 1.01-1.07).

CONCLUSIONS

Professional ballet companies should implement training principles such as periodization and progression, particularly in the case of senior-ranking dancers, older dancers, and dancers with high rates of previous injury. These findings provide a basis for future prospective investigations into specific causal injury pathways.

Prevalence and Burden of Self-Reported Health Problems in Junior Male Elite Ice Hockey Players: A 44-Week Prospective Cohort Study

BACKGROUND

Little is known about the burden of overuse injuries and illnesses in junior elite ice hockey.

PURPOSE

To describe the prevalence and burden of all health problems in junior male elite ice hockey players in Norway during 1 school year.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

A total of 206 junior male ice hockey players (mean age, 17 years; range, 15-20 years) attending specialized sports academy high schools in Norway reported all health problems, acute injuries, overuse injuries, and illnesses, weekly during the 2018-2019 school year (44 weeks). The players self-reported injuries and illnesses using the Oslo Sports Trauma Research Center Questionnaire on Health Problems.

RESULTS

Of the players included, 25% (95% CI, 23%-27%) reported at least 1 health problem at any given time, while 16% (95% CI, 14%-17%) experienced health problems with a substantial negative effect on training and performance. Of the total burden of health problems, acute injuries accounted for 44%, overuse injuries 31%, and illnesses 25%. For acute injuries, the greatest burden was caused by injuries to the ankle, knee, and hand, whereas for overuse injuries the most burdensome location was the hip/groin and knee.

CONCLUSION

This study documented that while acute injuries did represent the greatest problem among junior elite ice hockey players, overuse injuries, especially to the knee and hip/groin, also had a substantial effect.

Despite maintaining a high daily training availability, a quarter of athletes start the season injured and three quarters experience injury in an Australian State Academy of Sport

OBJECTIVES

To 1) investigate the incidence, prevalence, burden and characteristics of injuries; and 2) explore the frequency of physiotherapy and medical servicing for elite sports academy athletes over a 12-month season.

DESIGN

Prospective cohort study.

METHODS

Medical attention and time-loss injuries were prospectively recorded by Physiotherapy and Medical (Sports Physician) staff for 94 athletes (72.3% females). The number of linked physiotherapy and medical servicing appointments was also recorded. Injury incidence rates (IIR), point and period prevalence, and injury burden were calculated and compared by athlete gender, sport, and categorisation (performance level) using incidence rate ratios (IRR).

RESULTS

The number of injuries reported was 193 in 71 (75.5%) athletes. The IIR was 2.1 (95%CI: 1.8 to 2.4) injuries per 365 days, with no gender difference observed (IRR: 1.1, 0.8 to 1.4). The injury burden was 43.5 (95%CI: 37.8 to 50.1) days absent per 365 days. More than one-quarter (point prevalence, 26.6%) of athletes commenced the season with an injury. In-season injury risk was 2.5 fold greater in athletes who started the season with an injury compared to athletes who started the season without an injury (IRR: 2.5, 1.9 to 3.4). The majority (81.2%) of the 1164 appointments recorded were physiotherapy, with an overall 4.3:1.0 physiotherapy to medical appointment ratio.

CONCLUSIONS

One in four athletes began the elite pathway season with a pre-existing injury, while also demonstrating a 2.5 fold greater risk of subsequent injury in the scholarship period. Sports should not assume their athletes are uninjured at the beginning of their scholarship. Injury profiles, and physiotherapy and medical servicing varied across sports. To reduce health as a barrier in the successful transition of talented young athletes to elite athletes, injury management strategies at the commencement of recruitment and throughout the scholarship should be prioritised in the development pathway.

Injury profiles of Australian football players across five, women's and girls' competition levels

OBJECTIVES

To describe injury profiles of Australian football players and explore trends across five, women's and girls' competition levels.

DESIGN

Prospective cohort study.

METHODS

Injuries were prospectively recorded by team personnel across one or two seasons of Australian football (2017-18 and/or 2018-19) including five, women's and girls' competition levels (elite senior, non-elite senior, high-level junior, non-elite junior (14-17 years), and non-elite junior (10-13 years)). Injury incidence rates were calculated per 1000 h and injury prevalence calculated for pre-season, early-season, mid-season, and late-season. Descriptive statistics present injury profiles according to activity, body region, pathology, mechanism, and severity.

RESULTS

From the 392 included players, 760 injuries were recorded. Overall injury incidence was 20.9 injuries per 1000 h. Injury prevalence was highest during pre-season (64.1%). Most injuries were to the lower extremity (n = 440; 58.0%). Ligament/joint sprain injuries were common (n = 147, 19.3%). Several injuries resulted from contact mechanisms (n = 314, 61.4%), with many due to contact with another player (n = 131, 52.8%). Injuries resulting in time lost from participation were common (n = 444, 58.9%). Competition level injury trends were observed, with elite senior (125.1 injuries per 1000 h) and high-level junior (116.9 injuries per 1000 h) players having greater match injury incidence compared to their non-elite counterparts (15.5-41.4 injuries per 1000 h).

CONCLUSIONS

This study provides preliminary insight into injury profiles of Australian football players in women's and girls' competitions. These findings can drive future injury risk reduction research specific to this population across the developmental pathway.

The influence of growth and training loads on injury risk in competitive trampoline gymnasts

There is currently limited research exploring the relationship between growth, training load and injury in gymnasts. Twenty-one national level, trampoline gymnasts recorded training load and injury for 8-weeks. Percentage of predicted adult height (%PAH) was calculated using the Khamis-Roche method and used to define growth spurt status. Training load was calculated using the session rate of perceived exertion and analysed as differential loads and as a 7-day exponentially weighted moving average (EWMA7day). There was a significant non-linear association between %PAH and the probability of injury when adjusting for either training load metric (differential load, P = 0.015; EWMA7day; P = 0.008), with the highest injury risk estimated at ~90% PAH (circa growth spurt). The probability of injury significantly increased with increases in EWMA7day training load (RR: 1.88 95% CI: 1.21- 2.91, P = 0.005) but not with differential load. No significant interaction between %PAH, training load and the probability of injury were observed. Data suggest that competitive trampoline gymnasts are at an increased risk of injury during the adolescent growth spurt or with higher weekly training loads. Coaches should be educated and encouraged to identify periods of rapid growth and monitor training load, to reduce the risk of injury.

Injury patterns differ with age in male youth football: a four-season prospective study of 1111 time-loss injuries in an elite national academy

OBJECTIVES

To describe age group patterns for injury incidence, severity and burden in elite male youth football.

METHODS

Prospective cohort study capturing data on individual exposure and time-loss injuries from training and matches over four seasons (2016/2017 through 2019/2020) at a national football academy (U13-U18; age range: 11-18 years). Injury incidence was calculated as the number of injuries per 1000 hours, injury severity as the median number of days lost and injury burden as the number of days lost per 1000 hours.

RESULTS

We included 301 players (591 player-seasons) and recorded 1111 time-loss injuries. Overall incidence was 12.0 per 1000 hours (95% CI 11.3 to 12.7) and burden was 255 days lost per 1000 hours (252 to 259). The mean incidence for overall injuries was higher in the older age groups (7.8 to 18.6 injuries per 1000 hours), while the greatest burden was observed in the U16 age group (425 days; 415 to 435). In older age groups, incidence and burden were higher for muscle injuries and lower for physis injuries. Incidence of joint sprains and bone stress injuries was greatest for players in the U16, U17 and U18 age groups, with the largest burden observed for U16 players. No clear age group trend was observed for fractures.

CONCLUSION

Injury patterns differed with age; tailoring prevention programmes may be possible.

Injuries and Training Practices in Competitive Adolescent Distance Runners: A Retrospective Cross-Sectional Study

Background: Distance running is one of the most popular sports around the world. The epidemiology of running-related injury (RRI) has been investigated in adults, but few studies have focused on adolescent distance runners. Objectives: (1) To provide descriptive epidemiology of RRI (risks, rates, body regions/areas, and severity) and examine the training practices (frequency, volume, and intensity) of competitive adolescent distance runners (13-18 years) in England, and (2) to describe potential risk factors of RRI. Methods: A cross-sectional study design was used. Adolescent distance runners (n = 113) were recruited from England Athletics affiliated clubs. Participants voluntarily completed an online questionnaire between April and December 2018. At the time of completion, responses were based on the participant's previous 12-months of distance running participation. Incidence proportions (IP) and incidence rates (IR) were calculated. Results: The IP for "all RRI" was 68% (95% CI: 60-77), while the IR was 6.3/1,000 participation hours (95% CI: 5.3-7.4). The most commonly injured body areas were the knee, foot/toes, and lower leg; primarily caused by overuse. The number of training sessions per week (i.e., frequency) significantly increased with chronological age, while a large proportion of participants (58%) self-reported a high level of specialisation. Conclusions: RRI is common in competitive adolescent distance runners. These descriptive data provide guidance for the development of RRI prevention measures. However, analytical epidemiology is required to provide better insight into potential RRI risk factors in this specific population.

Methods for epidemiological studies in competitive cycling: an extension of the IOC consensus statement on methods for recording and reporting of epidemiological data on injury and illness in sport 2020

In 2020, the IOC released a consensus statement that provides overall guidelines for the recording and reporting of epidemiological data on injury and illness in sport. Some aspects of this statement need to be further specified on a sport-by-sport basis. To extend the IOC consensus statement on methods for recording and reporting of epidemiological data on injury and illness in sports and to meet the sport-specific requirements of all cycling disciplines regulated by the Union Cycliste Internationale (UCI). A panel of 20 experts, all with experience in cycling or cycling medicine, participated in the drafting of this cycling-specific extension of the IOC consensus statement. In preparation, panel members were sent the IOC consensus statement, the first draft of this manuscript and a list of topics to be discussed. The expert panel met in July 2020 for a 1-day video conference to discuss the manuscript and specific topics. The final manuscript was developed in an iterative process involving all panel members. This paper extends the IOC consensus statement to provide cycling-specific recommendations on health problem definitions, mode of onset, injury mechanisms and circumstances, diagnosis classifications, exposure, study population characteristics and data collection methods. Recommendations apply to all UCI cycling disciplines, for both able-bodied cyclists and para-cyclists. The recommendations presented in this consensus statement will improve the consistency and accuracy of future epidemiological studies of injury and illness in cycling.

Injury risks among elite competitive alpine skiers are underestimated if not registered prospectively, over the entire season and regardless of whether requiring medical attention

PURPOSE

Prospective studies assessing the injuries occurring in elite competitive alpine skiers are lacking, and a full picture of all injuries, including those not requiring medical attention, is absent. Likewise, little is known about the sex-specific injury risks and patterns of elite skiers throughout an entire season (i.e. an off-season preparation period and a competition period). Accordingly, this study investigated the injuries of a national team cohort with respect to season period and sex.

METHODS

Over an entire season, all injuries occurring in 44 Swiss National Ski Team members (25 females and 19 males) were registered, regardless of whether they required medical attention. Skiers were prospectively monitored by the Oslo Sports Trauma Research Centre (OSTRC) questionnaire and by continuously updated team medical records. Finally, these data were used as a reference for supplemental interviews, in which the correctness and completeness of the prospective data were verified.

RESULTS

The risk of suffering at least one injury during an entire season was 75.0% with a 95% confidence interval (73.1%, 76.9%) for traumatic injuries, and 52.3% (50.0%, 54.5%) for overuse injuries. Traumatic injuries concerned the head, lower leg and knee, while overuse injuries affected the lumbar spine, knee and hip. During the competition period, skiers were more prone to traumatic injuries, while during the off-season preparation period, skiers' risk was higher for overuse injuries. Over an entire season, there were no sex differences. However, females were more vulnerable to traumatic injuries during the preparation period and overuse injuries during the competition period, while males had a higher risk for overuse injuries during the preparation period.

CONCLUSIONS

When prospectively registering injuries among elite competitive alpine skiers over an entire season, regardless of whether the injuries required medical attention, the injury risks were alarmingly high and substantially larger than those previously reported. Moreover, since injury risks and patterns are season period and sex dependent, it is strongly recommended that (1) injury registration focuses on both the off-season preparation period and the competition period and (2) prevention efforts are specifically tailored to the sex of the athletes.

LEVEL OF EVIDENCE

II.

Match High-Speed Running Distances Are Often Suppressed After Return From Hamstring Strain Injury in Professional Footballers

BACKGROUND

High-speed running is commonly implicated in the genesis of hamstring injury. The success of hamstring injury management is typically quantified by the duration of time loss or reinjury rate. These metrics do not consider any loss in performance after returning to play from hamstring injury. It is not known to what extent high-speed running is altered on return to play after such injury.

HYPOTHESIS

Match high-speed running distance will change after returning from hamstring injury.

STUDY DESIGN

Non-randomized cohort.

LEVEL OF EVIDENCE

Level 3.

METHODS

Match high-speed running distance in highest level professional football (soccer, Rugby League, Rugby Union, and Australian Rules) were examined for a minimum of 5 games prior and subsequent to hamstring strain injury for individual differences using a linear regression models approach. A total of 22 injuries in 15 players were available for analysis.

RESULTS

Preinjury cumulative high-speed running distances were strongly correlated for each individual (r2 = 0.92-1.0; P < 0.0001). Pre- and postinjury high-speed running data were available for a median of 15 matches (range, 6-15). Variance from the preinjury high-speed running distance was significantly less (P = 0.0005) than the post injury values suggesting a suppression of high-speed running distance after returning from injury. On return to play, 7 of the 15 players showed a sustained absolute reduction in preinjury high-speed running distance, 7 showed no change, and 1 player (only) showed an increase. Analysis of subsequent (second and third injury) return to play showed no differences to return from the index injury.

CONCLUSION

Return to play was not associated with return to high-speed running performance for nearly half of the players examined, although the same number showed no difference. Persisting deficits in match high-speed running may exist for many players after hamstring strain injury.

CLINICAL RELEVANCE

Returning to play does not mean returning to (high-speed running) performance for nearly half of the high-level professional football players examined in this study. This suggests that successful return to play metrics should be expanded from simple time taken and recurrence to include performance.

A qualitative investigation into the individual injury burden of amateur rugby players

OBJECTIVE

To examine the individual experiences of injury burden in amateur Rugby players across the onset of injury, rehabilitation, and return to play.

DESIGN

Qualitative.

SETTING

Irish amateur Rugby clubs.

PARTICIPANTS

Three male and two female Rugby players who sustained a severe injury that resulted in a time loss of at least 28 days.

MAIN OUTCOME MEASURES

Semi-structured interviews were used to explore the injury burden experienced during the three phases of injury.

RESULTS

Hierarchical content analysis revealed 36 codes representing individual injury burden, which were clustered into seven themes across personal (emotional reaction; impact on performance or involvement; lack of knowledge; severity of injury and incapacitation) and situational (exposure to others playing; negative experiences with treatment or rehabilitation; societal burden) dimensions.

CONCLUSIONS

The findings indicate that individual injury experiences can affect a player's recovery and rehabilitation outcome, potentially extending the injury process and affecting player availability for the team. As such, injury management should focus on alleviating any injury-related burden experienced by players, as well as burden placed on the team, to maximise rehabilitation outcomes.

Injury epidemiology in professional ballet: a five-season prospective study of 1596 medical attention injuries and 543 time-loss injuries

OBJECTIVES

To describe the incidence rate, severity, burden and aetiology of medical attention and time-loss injuries across five consecutive seasons at a professional ballet company.

METHODS

Medical attention injuries, time-loss injuries and dance exposure hours of 123 professional ballet dancers (women: n=66, age: 28.0±8.3 years; men: n=57, age: 27.9±8.5 years) were prospectively recorded between the 2015/2016 and 2019/2020 seasons.

RESULTS

The incidence rate (per 1000 hours) of medical attention injury was 3.9 (95% CI 3.3 to 4.4) for women and 3.1 (95% CI 2.6 to 3.5) for men. The incidence rate (per 1000 hours) of time-loss injury was 1.2 (95% CI 1.0 to 1.5) for women and 1.1 (95% CI 0.9 to 1.3) for men. First Soloists and Principals experienced between 2.0-2.2 additional medical attention injuries per 1000 hours and 0.9-1.1 additional time-loss injuries per 1000 hours compared with Apprentices (p≤0.025). Further, intraseason differences were observed in medical attention, but not time-loss, injury incidence rates with the highest incidence rates in early (August and September) and late (June) season months. Thirty-five per cent of time-loss injuries resulted in over 28 days of modified dance training. A greater percentage of time-loss injuries were classified as overuse (women: 50%; men: 51%) compared with traumatic (women: 40%; men: 41%).

CONCLUSION

This is the first study to report the incidence rate of medical attention and time-loss injuries in professional ballet dancers. Incidence rates differed across company ranks and months, which may inform targeted injury prevention strategies.

Is the Acute: Chronic Workload Ratio (ACWR) Associated with Risk of Time-Loss Injury in Professional Team Sports? A Systematic Review of Methodology, Variables and Injury Risk in Practical Situations

BACKGROUND

The acute: chronic workload ratio (ACWR) is an index of the acute workload relative to the cumulative chronic workloads. The monitoring of physical workloads using the ACWR has emerged and been hypothesized as a useful tool for coaches and athletes to optimize performance while aiming to reduce the risk of potentially preventable load-driven injuries.

OBJECTIVES

Our goal was to describe characteristics of the ACWR and investigate the association of the ACWR with the risk of time-loss injuries in adult elite team sport athletes.

DATA SOURCES

PubMed, EMBASE and grey literature databases; inception to May 2019.

ELIGIBILITY CRITERIA

Longitudinal studies that assess the relationship of the ACWR and time-loss injury risk in adult professional or elite team sports.

METHODS

We summarized the population characteristics, workload metrics and ACWR calculation methods. For each workload metric, we plotted the risk estimates for the ACWR in isolation, or when combined with chronic workloads. Methodological quality was assessed using a modified version of the Downs and Black scale.

RESULTS

Twenty studies comprising 2375 injuries from 1234 athletes (all males and mean age of 24 years) from different sports were included. Internal (65%) and external loads (70%) were collected in more than half of the studies and the session-rating of perceived exertion and total distance were the most commonly collected metrics. The ACWR was commonly calculated using the coupled method (95%), 1:4 weekly blocks (95%) and subsequent week injury lag (80%). There were 14 different binning methods with almost none of the studies using the same binning categories.

CONCLUSION

The majority of studies suggest that athletes are at greater risk of sustaining a time-loss injury when the ACWR is higher relative to a lower or moderate ACWR. The heterogenous methodological approaches not only reflect the wide range of sports studied and the differing demands of these activities, but also limit the strength of recommendations.

PROSPERO REGISTRATION NUMBER

CRD42017067585.