The epidemiology of injury for an elite junior Australian Football cohort

Changes in injury and illness incidence and burden in elite junior male Australian footballers over a 6-year period

OBJECTIVES

The study aimed to determine a contemporary multi-year junior Australian football (AF) injury and illness profile and secondly, explore changes in incidence and burden over the six-year period.

DESIGN

Prospective cohort study.

METHODS

This study involved an elite male junior Under-18 competition and included six seasons of injury data between 2015 and 2021. A total of 1559 eligible players were included in the analysis. An injury was defined as 'any physical or medical condition that resulted in a player missing one or more regular competition season matches.' A Poisson regression model determined injury and illness incidence and burden across the league over a 6-year period and explored changes in injury incidence and burden over time.

RESULTS

The frequency of injuries was 1023 over the six seasons. The most frequently reported injuries were ankle sprain or joint injuries (26.5 injuries/season), hamstring strains (15.8 injuries/season), and concussion (15.1 injuries/season). The most burdensome injuries were ankle sprain or joint injuries with 82.5 missed matches/season, followed by anterior cruciate ligament injuries with 53.7 missed matches/season and hamstring strains with 46.9 missed matches/season. Injury incidence did not change for the most common injury types over time (all p > 0.05). Injury burden significantly increased for concussions, ACL injuries, MCL injuries, and ankle sprain or joint injuries (all p < 0.05).

CONCLUSIONS

The multi-year injury surveillance methodology identified injuries with the highest consistent incidence and those that caused the most burden to elite male junior AF players. The results can be used to reliably guide future injury prevention methodologies to reduce the impact on players and clubs.

Does changing the Functional Movement Screen composite score threshold influence injury risk estimation in junior Australian football players?

This study aimed to identify whether a revised lower Functional Movement Screen (FMS) composite score threshold would be associated with a greater injury risk for junior athletes than the common threshold of≤14. This prospective cohort study included tracking of 809 elite junior male Australian football players for injuries that resulted in a missed game. All athletes completed pre-season FMS testing and a 12-month self-reported retrospective injury questionnaire. Analyses examined the relationship between composite score thresholds of≤14, ≤13, and≤12 and the risk of injury. The relationship between prospective injury and the common composite threshold score of ≤ 14 was dependent on the presence of a recent injury history (relative risk [RR] = 1.45, p = 0.004) in comparison to no recent injury history (RR = 0.98, p = 0.887). Scoring≤12 in the presence of a recent injury history had the greatest diagnostic accuracy but only a trivial increase in injury risk (RR = 1.59, p = 0.001, sensitivity = 0.35, specificity = 0.80, negative and positive likelihood ratios = 0.81 and 1.75). Whilst some small statistical relationships existed between prospective injury and the FMS composite score thresholds, all three thresholds were not associated with a clinically meaningful relationship with prospective injury and were no more effective than retrospective injury for determining athletes at risk of injury.

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.

Return to play protocols for musculoskeletal upper and lower limb injuries in tackle-collision team sports: A systematic review

Athletes in tackle-collision teams are at high risk of musculoskeletal injuries resulting in absence from play due to the high impact nature of the sport. There is a paucity of research to guide the management and assessment methods needed to facilitate the return to play (RTP) process. This review aimed to describe, synthesise and evaluate RTP protocols implemented for musculoskeletal injuries in tackle-collision teams. A systematic search of Scopus, PubMed, Web of Science and Ebsco Host was conducted for RTP management protocols and assessment modalities following upper and lower limb musculoskeletal injuries in tackle-collision team athletes. Prospective and retrospective quantitative controlled trials, cohort, case-control, case-series and cross-sectional observation studies published between January 2000 and March 2020 were considered. The main outcome measures were the proportion of athletes to RTP, associated time-loss and reinjury risk. 5265 articles were screened. 34 studies met the eligibility criteria of which 23 involved management and 11 assessment modalities. Management involved surgical or conservative strategies along with exercise-based rehabilitation. Assessment modalities included radiographic assessment, clinical evaluation and subjective ratings. Promising RTP management included progressive weight-bearing and exercised-based rehabilitation for ankle sprains as well as surgery, the use of a sling and exercise-based rehabilitation for shoulder instability. MRI scans showed promise in predicting time-loss following hamstring and calf strains in tackle-collision athletes. There are currently no clear guidelines for RTP after musculoskeletal injuries in tackle-collision sports. Future research should investigate efficient management strategies evaluated through valid and reliable assessment methods to better guide clinicians.

Lower limb MSK injuries among school-aged rugby and football players: a systematic review

OBJECTIVE

The objective of this systematic review was to explore the incidence of lower limb musculoskeletal (MSK) injuries sustained by rugby union, rugby league, soccer, Australian Rules and Gaelic football players under 18 years. The review sought to identify the mechanisms and types of injury sustained and to compare between sports.

DESIGN

This systematic review focused on the incidence of lower limb injury in adolescent team sports that involved running and kicking a ball. A literature search of studies published prior to January 2020 was conducted using SportDiscus, Medline and PubMed databases. The Standard Quality Assessment Criteria appraisal tool was used to assess the quality of each article included in the review. Two or more authors independently reviewed all papers.

RESULTS

Sixteen papers met the inclusion criteria; prospective cohort (N=14), retrospective (n=1) and longitudinal (n=1). These studies investigated injuries in rugby union and rugby league (n=10), football (soccer) (n=3), Australian Rules (n=2) and Gaelic football (n=1). There were a total of 55 882 participants, aged 7-19 years old, who reported 6525 injuries. The type, site and mechanisms of injury differed across sports.

SUMMARY

Lower limb injuries were common in adolescent rugby, soccer, Gaelic football and Australian Rules football players, however these studies may not fully reflect the true injury burden where recurrent and overuse injuries have not been considered. There were differences between sports in the mechanisms, types and severity of injury.

Combining physical performance and Functional Movement Screen testing to identify elite junior Australian Football athletes at risk of injury

The Functional Movement Screen (FMS) and physical performance testing are often suggested to be related to sports injury risk. This study explored if the combination of FMS and physical performance testing improved identification of non-contact injury risk over FMS testing alone in an elite junior Australian football cohort. Over a 3-year period, 573 players completed pre-season injury history questionnaires, FMS, physical performance testing (20-m sprint, vertical jump, planned agility testing, and shuttle run test), and subsequent in-season injury surveillance. Results: Neither previous injury or FMS score <14 were related to an increased risk of subsequent injury in isolation. The combination of FMS composite score ≤14 and previous injury moderately increased the risk of injury (Hazard ratio [HR] = 2.22 [1.09-4.54]). None of the physical performance measures improved the ability to predict injuries based on FMS composite score. FMS asymmetry was only associated with injury when combined with previous injury and vertical jump performance. Players with ≥1 FMS asymmetry and history of previous injury experienced a large increase in injury risk when vertical jump was poor (HR = 4.26 [1.35-13.42]) or good (HR = 3.17 [1.08-9.29]). Players with a combination of a good vertical jump, no previous injury, and no FMS asymmetries were also at moderately increased risk of injury (HR = 3.41 [1.11-10.42]). No physical performance tests improved the ability to identify non-contact injury risk using an FMS composite score threshold. However, a U-shaped relationship between vertical jump and injury risk was identified with both poor and good vertical jump height associated with a moderate-large increase in non-contact injury risk in the presence of ≥1 asymmetrical FMS sub-test.

Absolute and Relative Load and Injury in Elite Junior Australian Football Players Over 1 Season

PURPOSE

To investigate the association between training and match loads and injury in elite junior Australian football players over 1 competitive season.

METHODS

Elite junior Australian football players (n = 290, age 17.7 [0.3] y, range 16-18 y) were recruited from the under-18 state league competition in Victoria to report load and injury information. One-week load (session rating of perceived exertion multiplied by duration) and all time-loss injuries were reported using an online sport-injury surveillance system. Absolute load measures (weekly sums) enabled the calculation of relative measures such as the acute:chronic workload ratio. Load measures were modeled against injury outcome (yes/no) using a generalized estimating equation approach, with a 1-wk lag for injury.

RESULTS

Low (<300 arbitrary units [au]) and high (>4650 au) 1-wk loads were associated with significantly higher risk of injury. Furthermore, low (<100 au) and high (>850 au) session loads were associated with a higher risk of injury. High strain values (>13,000) were associated with up to a 5-fold increase in the odds of injury. There was a relatively flat-line association between the acute:chronic workload ratio and injury.

CONCLUSIONS

This study is the first investigation of elite junior athletes demonstrating linear and nonlinear relationships between absolute and relative load measures and injury. Coaches should focus player loads on, or at least close to, the point at which injury risk starts to increase again (2214 au for 1-wk load and 458 au for session load) and use evidence-based strategies across the week and month to help reduce the risk of injury.

Functional Movement Screen Pain Location and Impact on Scoring Have Limited Value for Injury Risk Estimation in Junior Australian Football Players

OBJECTIVE

To describe the location and severity of pain during Functional Movement Screen (FMS) testing in junior Australian football players and to investigate its effect on FMS composite score and injury risk.

DESIGN

Prospective cohort study.

METHODS

Junior male Australian football players (n = 439) completed preseason FMS testing. Pain location and severity (on a 0-to-10 numeric pain-rating scale [NPRS]) were assessed for painful subtests. The FMS composite score was calculated using 3 scoring approaches: "traditional," a score of zero on painful subtests; "moderate," a score of zero on painful subtests if an NPRS pain severity was greater than 4; and "raw," did not adjust painful FMS subtest scores. Players were monitored throughout the competitive season and considered injured when 1 or more matches were missed due to injury.

RESULTS

One hundred seventy players reported pain during FMS testing. The pain-scoring approach affected mean composite score values (raw, 14.9; moderate, 14.5; traditional, 13.6; P<.001). Sixty-eight percent of pain was mildly severe (NPRS of 4 or less). Back pain (50%) was more common than upper-limb (24%) or lower-limb (26%) pain (P<.001). Upper-limb pain was associated with a small increase in injury risk (hazard ratio = 1.59, P = .023). No other FMS pain location influenced injury risk, nor did pain severity (P>.280). The FMS composite score was not associated with injury risk, regardless of pain-scoring approach (P≥.500).

CONCLUSION

Pain was common during FMS testing in junior Australian football players and had a notable effect on the FMS composite score, but minimal effect on subsequent injury risk. J Orthop Sports Phys Ther 2020;50(2):75-82. Epub 17 Sep 2019. doi:10.2519/jospt.2020.9168.

Profile and cost of sport and exercise-related hand and wrist injuries with Emergency Department presentation

OBJECTIVES

Injuries to the hand and wrist from sport and exercise are common and costly. This cost-of-illness analysis was performed to estimate the economic implications of hand and wrist injuries that were sustained as a result of participation during sport or exercise.

PERSPECTIVE

Cost estimates were calculated from resource use in the emergency, inpatient and outpatient settings from the perspective of one public healthcare service.

SETTING

Alfred Health, a large public health service with two emergency departments located in Victoria, Australia.

METHODS

This descriptive epidemiological study used ICD-10 diagnostic codes and electronic billing records to identify 778 potential cases for inclusion. Electronic medical records were screened and reviewed to extract demographic and patient care journey data.

RESULTS

692 individuals, (n=761 individual zone of injuries), were included. Australian Rules Football (ARF) was the largest contributor to injuries (20.2%) followed by riding bicycles (15.9%. The total cost of all injuries was $790,325, with a median cost per case of $278 [IQR $210-$282] in the Emergency Department n=692, $3328 [IQR $2242-$6441] in the inpatient setting n=76 and $630 [IQR $460-$870] in the outpatient setting n=244.

CONCLUSIONS

Hand and wrist injuries sustained from sport and exercise contribute to a significant financial burden on the healthcare system. Future research that considers the costs that occur outside of the public healthcare service is required estimate the burden associated with these injuries comprehensively. Injury prevention programs may mitigate the observed injury trends.

Australian Football League Injury Characteristics Differ Between Matches and Training: A Longitudinal Analysis of Changes in the Setting, Site, and Time Span From 1997 to 2016

Background:

Injury surveillance has been used to quantify the scope of the injury burden in Australian football. However, deeper statistical analyses are required to identify major factors that contribute to the injury risk and to understand how these injury patterns change over time.

Purpose:

To compare Australian Football League (AFL) injury incidence, severity, prevalence, and recurrence by setting, site, and time span from 1997 to 2016.

Study Design:

Descriptive epidemiology study.

Methods:

A total of 15,911 injuries and medical illnesses recorded by team medical staff at each club were obtained from the AFL’s injury surveillance system and analyzed using linear mixed models with 3 fixed effects (setting, time span, site) and 1 random effect (club). All types of injuries and medical illnesses were included for analysis, provided that they caused the player to miss at least 1 match during the regular season or finals. Five-season time spans (1997-2001, 2002-2006, 2007-2011, and 2012-2016) were used for comparisons. Incidence rates were expressed at the player level. Recurrences were recoded to quantify recurrent injuries across multiple seasons.

Results:

Compared with training injuries, match injuries had a 2.8 times higher incidence per season per club per player (matches: 0.070 ± 0.093; training: 0.025 ± 0.043; P < .001). Match injuries resulted in 1.9 times more missed matches per club per season (matches: 17.2 ± 17.0; training: 9.1 ± 10.5; P < .001). and were more likely to be recurrences (matches: 11.6% ± 20.0%; training: 8.6% ± 21.8%; P < .001). From the 1997-2001 to 2007-2011 time spans, overall injury severity increased from a mean of 3.2 to 3.7 missed matches (P ≤ .01). For the most recent 2012-2016 time span, injuries resulted in 3.6 missed matches, on average. Hip/groin/thigh injuries had the highest incidence (0.125 ± 0.120) and prevalence (19.2 ± 16.4) rates, and recurrences (29.3% ± 27.9%) were 15% more likely at this site than any other injury site.

Conclusion:

The risks of match injuries are significantly higher than those of training injuries in the AFL. Compared with the 1997-2001 time span, injuries became more severe during the 2007-2011 time span.

Effects of fatigue on ankle biomechanics during jumps: A systematic review

Fatigue is common during physical activity and can have an effect on ankle biomechanics during different actions, such as a jump. Yet current research on the topic is very heterogeneous and hinders clarity on what changes are actually due to fatigue. Therefore, the aim of this review was to summarise and analyse the current literature that investigates the effects of fatigue on ankle biomechanics during a jump. Searches were conducted in five databases and studies with activities eliciting fatigue and comparing outcomes under a fatigue and non-fatigue conditions were selected. Twelve studies were included, six analysed double legged jumps and six single legged jump. When comparing ankle biomechanics between a fatigued condition and a non-fatigued condition, findings suggested that at initial contact at landing, dorsiflexion increased in single legged jump and plantarflexion increased in double legged jump; at maximum knee flexion after landing, dorsiflexion decreased in double legged jumps and plantarflexion increased at full foot contact in single legged jumps. Also, ankle power (for double legged jump) and ground reaction force (for double and single legged jump) reduced at initial contact to maximum knee flexion at landing after fatigue and ankle power also reduced at takeoff in single legged jumps. The current review shows that fatigue affect ankle biomechanics by reducing dorsiflexion, from initial contact to maximum knee flexion at landing, and power during the jump takeoff. Such information could have implications for injury prevention.

Injury prevalence across sports: a descriptive analysis on a representative sample of the Danish population

Background

Physical activity plays an important role in public health, owing to a range of health-related benefits that it provides. Sports-related injuries are known to be an important barrier to continued physical activity. Still, the prevalence of injuries on a general population level has not yet been explored in a descriptive epidemiological investigation. The purpose of the questionnaire-based study, therefore, was to describe the prevalence of injury in a representative sample of the Danish population.

Methods

Two samples of 10,000 adults (> 15 years) and 6500 children and adolescents (7–15 years) were invited to respond to a web-based questionnaire. Of these, 3498 adults (35.0%) and 3221 children (49.6%) responded successfully. The definition of sports injury was time-loss and medical attention-based, inhibiting participants from sports activity for at least 7 days, and/or involved contact with a healthcare professional, respectively.

Results

Amongst adults, 642 (18.4% [95%CI: 17.1%; 19.6%]) reported to have had an injury within the past 12 months. Males reported significantly more injuries than females (difference in prevalence proportion: 9.2%-points [95%CI: 6.7%-points; 11.8%-points]). The prevalence of injuries was greatest in running (n_inj = 198), football (n_inj = 94) and strength training (n_inj = 89).

Amongst children, 621 (19.3% [95%CI: 17.9%; 20.6%]) had been injured. No difference in injury prevalence proportion existed between boys and girls. The prevalence of injuries was greatest in football (n_inj = 235), handball (n_inj = 86) and gymnastics (n_inj = 66).

Conclusions

Sports injuries seem to be very frequent in Denmark, since a total of 18.4% of the adults and 19.3% of the children reported having had one or more injuries within the past 12 months, equal to either time lost with physical activity and/or contact to the health care system.

The relationship of hip muscle performance to leg, ankle and foot injuries: a systematic review

OBJECTIVES

Hip control affects movement and muscle firing patterns in the leg, ankle and foot, and may contribute to overuse injuries. Muscle performance can be measured as strength, endurance or muscle activation patterns. Our objective was to systematically review whether hip muscle performance is associated with leg, ankle and foot injuries.

DATA SOURCES

A structured and comprehensive search of six medical literature databases was combined with forward and backward citation tracking (AMED, CINAHL, EMBASE, Medline, Scopus and SportDiscus).

STUDY SELECTION

Eligible studies measured hip muscle performance in individuals with musculoskeletal injuries below the tibial tuberosity, using dynamometry or electromyography (EMG). All studies compared an injured group with a control group or compared the injured and non-injured limb in the same individual.

DATA EXTRACTION

Data was extracted from each study independently by two authors.

DATA SYNTHESIS

Twenty case-control and four prospective studies (n = 24) met the inclusion criteria. Injury classifications included chronic ankle instability (n = 18), Achilles tendinopathy (n = 2), medial tibial stress syndrome and tibial stress fracture (n = 1), posterior tibial tendon dysfunction (n = 1), and exertional medial tibial pain (n = 2). Eleven of the studies revealed differences in hip muscle performance indicating less strength, delayed onset activation and decreased duration of activation in the injured groups. Two studies found evidence for differences between groups only in some of their measurements. Three out of the four prospective studies revealed that hip muscle performance was not a risk factor for leg, ankle and foot injuries.

CONCLUSIONS

This review provides limited evidence that hip muscle performance variables are related to leg, ankle and foot injuries. Emerging evidence indicates this might be a result of the injury rather than a contributor to the injury.

High prevalence of dysfunctional, asymmetrical, and painful movement in elite junior Australian Football players assessed using the Functional Movement Screen

OBJECTIVES

The purpose of this study was to describe the prevalence of dysfunctional, asymmetrical, and painful movement in junior Australian Football players using the Functional Movement Screen (FMS).

DESIGN

Cross-sectional study.

METHODS

Elite junior male Australian Football players (n=301) aged 15-18 years completed pre-season FMS testing. The FMS consists of 7 sub-tests: deep squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, trunk stability push-up (TSPU) and rotary stability. The shoulder mobility, TSPU, and rotary stability tests were combined with an accompanying clearing test to assess pain. Each sub-test was scored on an ordinal scale from 0 to 3 and summed to give a composite score out of 21. Composite scores ≤14 were operationally defined as indicating dysfunctional movement. Players scoring differently on left and right sides were considered asymmetrical. Players reported whether they missed any games due to injury in the preceding 22 game season.

RESULTS

Sixty percent of players (n=182) had composite scores ≤14, 65% of players (n=196) had at least one asymmetrical sub-test, and 38% of players (n=113) had at least one painful sub-test. Forty-two percent of players (n=126) missed at least one game in the previous season due to injury. Previous injury did not influence composite score (p=0.951) or asymmetry (p=0.629). Players reporting an injury during the previous season were more likely to experience pain during FMS testing (odds ratio 1.97, 95% confidence interval 1.23-3.18; p=0.005).

CONCLUSIONS

Junior Australian Football players demonstrate a high prevalence of dysfunctional, asymmetrical, and painful movement during FMS testing.

Annual improvement in fitness test performance for elite junior Australian football cohorts

OBJECTIVES

The study examined the change in fitness test performance of elite junior Australian football cohorts tested over the span of seven years.

DESIGN

Annual cross-sectional observation study.

METHODS

A total of 1714 elite junior male Australian football players were eligible for the study and completed annual late pre-season fitness testing between 2009 and 2015. The testing comprised anthropometric (height, mass, and skinfolds) and performance tests (standing vertical jump, left and right foot running vertical jumps, 5- and 20-m sprinting, agility, and shuttle run test). A linear regression analysed the performance change for each test over time for two analyses: (1) the entire cohort, and (2) a stratified analysis of 'high' (top 20% of players) and 'low' (bottom 20% of players) performers for each performance test.

RESULTS

There was a moderate (f(2)=0.20) improvement in the standing vertical jump for the entire cohort. Small (f(2)≥0.03) changes occurred for the right and left foot running vertical jumps, agility, and shuttle run, whilst trivial/small (f(2)≤0.02) changes were observed for skinfolds, 5- and 20-m sprinting for the entire cohort. The most notable difference in the stratified analysis was that the 'low' performance groups had a greater improvement in the shuttle run, and 5- and 20-m sprinting.

CONCLUSIONS

Findings indicate a small overall annual improvement in fitness test performance of elite junior cohorts over time that seems to permeate through both 'high' and 'low' performers for most tests. The results might suggest an increase in the professionalism of players and junior developmental pathways.

The relationship between pre-season fitness testing and injury in elite junior Australian football players

OBJECTIVES

Australian Football (AF) is a collision sport containing high injury rates in junior competition. Successful performance at the elite junior level not only requires superior specific football knowledge and skills, but also well developed fitness qualities. However, no studies have examined the link between physical fitness qualities and injury in AF.

DESIGN

Prospective cohort.

METHODS

Injury data were collected through the use of a Player Movement Record (PMR) and a standardized Injury Report Form (IRF). Fitness test data was collected during the pre-season of the 2010 and 2011 seasons.

RESULTS

382 players consented to participate in the study. The cohort experienced an injury incidence rate of 24.29/standardized club (40 players/club). A faster 5-m sprint was associated with 'injury status' (p=0.016) and a 'knee' region (p≤0.001) injury. A faster planned agility score was associated with an increased risk of a 'hip/groin/thigh' region (p=0.010) injury, and specifically a 'quadriceps strain' (p=0.005). A lower 20-m shuttle run was associated with an increased risk of a 'shin/ankle/foot' (p=0.045) injury. Increased injury severity was associated with a higher left foot running vertical jump (VJ) (p=0.040), and faster 5-m sprint (p=0.043).

CONCLUSIONS

Lower aerobic endurance, faster 5-m acceleration and greater planned agility were associated with an increased risk of various injury types in elite junior AF players. Furthermore, a higher left foot running VJ and faster 5-m acceleration were associated with injury severity. These results may largely relate to a greater work capacity placing a higher load upon the musculoskeletal system in contact and non-contact situations.