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.

Efficacy of the FIFA cooling break heat policy during an intermittent treadmill football simulation in hot conditions in trained males.

OBJECTIVE: To evaluate the efficacy of the Fédération Internationale de Football Association (FIFA) cooling break policy against alternative cooling configurations in attenuating thermal strain during simulated football in the heat. METHODS: 12 males (age: 27±6 years, V̇O2peak: 61±7 mL/kg/min) completed five 90 min intermittent treadmill football match simulations in 40°C and 41% relative humidity (32°C wet-bulb globe temperature) with different cooling configurations: regular match without cooling breaks (REG), 3 min breaks without cooling (BRKno-cool), 3 min breaks with cooling (BRKcool: current FIFA policy; chilled fluid ingestion and ice towel across neck and shoulders), 5 min extended half-time without cooling breaks (ExtHTonly) and 3 min cooling breaks with 5 min ExtHT (ExtHTcool). Rectal temperature (Tre), heart rate, whole-body sweat rate (WBSR) and rating of perceived exertion (RPE) were recorded. Data are presented as mean (95% CIs). RESULTS: Final Tre was lower in BRKno-cool (0.20°C (0.01, 0.39), p=0.038), BRKcool (0.39°C (0.21, 0.57), p<0.001) and ExtHTcool (0.40°C (0.22, 0.58), p<0.001) than REG (39.1°C (38.8, 39.3)). Mean Tre was lower in ExtHTcool (38.2°C (38.0, 38.4)) than BRKcool (38.3°C (38.1, 38.5), p=0.018), BRKno-cool and ExtHTonly (38.4°C (38.2, 38.6), p<0.001) and REG (38.5°C (38.3, 38.7), p<0.001). Mean heart rate was lower during BRKcool (6 beats/min (4, 7), p<0.001) and ExtHTcool (7 beats/min (6, 8), p<0.001) compared with REG. WBSR was comparable across trials (p≥0.07) and RPE was attenuated during BRKcool (0.4 (0.1, 0.7), p=0.004) and ExtHTcool (0.5 (0.2, 0.7), p=0.002), compared with REG. CONCLUSION: BRKcool and ExtHTcool attenuated thermal, cardiovascular and perceptual strain during a simulated football match in the heat. Additional strategies may be required in field settings or under harsher conditions.

Performing Lower-Limb Strength Exercises Before or After Training Does not Influence Fatigue Indices in Competitive Youth Soccer Players.

ABSTRACT: Gantzer, C, Huff, D, Butterick, B, Chalmers, S, Marshall, P, Lovell, R, and Siegler, JC. Performing lower-limb strength exercises before or after training does not influence fatigue indices in competitive youth soccer players. J Strength Cond Res XX(X): 000-000, 2024-A multicenter approach was used to conduct a controlled, laboratory-based study (Part A) in conjunction with an ecologically focused, field-based study (Part B) of the influence of timing on hamstring fatigue induced by lower-limb strength exercises. Part A required players to perform the FIFA 11+ warm-up before a simulated soccer training session, whereas the other session involved removing the lower-limb strength exercises from the warm-up and delivering them after the simulated session. For Part B, players completed 2 live training sessions, where one session included the Nordic hamstring exercise (NHE) as part of a standardized warm-up before training and the other session incorporated the NHE at the end of training. Maximal hamstring force (MVC), rate of force development (RFD), countermovement jump (CMJ), and sprint speed (SS) were assessed before, during, and after the simulation and field training, respectively, to quantify fatigue across both study cohorts. There was no suggestion that timing of the intervention had an influence fatigue in either Part A or B, with no condition (MVC [Part A & B]: p > 0.43; RFD: p = 0.43; CMJ: p = 0.10; SS: p = 0.62), time (MVC: p > 0.30; RFD: p = 0.72; CMJ: p = 0.87; SS: p = 0.85), or interactions (MVC: p > 0.93; RFD: p = 0.78; CMJ: p = 0.99; SS: p = 0.94) evident. Our findings suggest youth soccer coaches should not be concerned with the timing of interventions, allowing them to focus instead on adherence and player buy-in.

Ankle sprain, concussion, and anterior cruciate ligament injuries are common and burdensome in sub-elite female Australian football players.

OBJECTIVES: To describe the epidemiology of injuries in sub-elite female Australian Football (AF). DESIGN: Prospective cohort. METHODS: 424 athletes were tracked across a 12-match season. Injury characteristics (location, severity, mechanism) were reported. Injury incidence (injuries per 1000 h) and injury burden (days absent per 1000 h) were calculated. Severity was considered as the number of days missed between injury onset and return to full training. Incidence was compared using incidence rate ratios, and severity using a Mann-Whitney U test. RESULTS: Total injury incidence was 10.8 (95 % confidence interval [CI] = 9.0, 12.8) injuries per 1000 h. Match incidence was 34.6 (95 % CI = 28.0, 42.4) injuries per 1000 h. Ankle sprain injuries (2.2 per 1000 h, 95 % CI = 1.4, 3.1) and concussion (1.6 per 1000 h, 95 % CI = 1.0, 2.5) injuries were the most frequent, followed by anterior cruciate ligament (ACL) injuries (0.9 per 1000 h, 95 % CI = 0.4, 1.6). ACL (40.4 days per 1000 h, 95 % CI = 36.9, 44.1), ankle sprain injuries (31.4 per 1000 h, 95 % CI =28.4, 34.7), and concussion (19.9 per 1000 h, 95 % CI = 17.5, 22.5) injuries were also the most burdensome. There were 78 mild, 34 moderate, and 21 severe injuries. ACL injuries were the most severe injury (56.0 [77.0] in-season days missed). CONCLUSIONS: This research describes the first large-scale injury profile of sub-elite female AF, reporting time-loss measures of incidence and burden for many injury types. Ankle sprain injuries, concussions, and ACL injuries are common and burdensome, and should be prioritised for prevention.

The impact of concussion on subsequent injury risk in elite junior Australian football athletes.

OBJECTIVES: Concussion increases injury risk. However, this has not been investigated in junior Australian football and it is unknown whether the location, severity, and mechanism of subsequent injuries differ after concussion vs. non-concussion injury. DESIGN: Prospective cohort. METHODS: 1455 elite adolescent male Australian footballers were tracked across seven seasons to determine whether subsequent injury risk was greater after concussion compared to non-concussion index injury using multilevel survival analysis. Mixed-effects logistic regression compared location and mechanism. Mixed-effects Poisson regression compared severity. RESULTS: Of 1455 athletes, 632 were injured and included in subsequent-injury analysis. There were no differences in injury incidence after a concussion compared to upper- (hazard ratio = 1.0, 0.6 to 1.9, P = 0.892; trivial effect) and lower (hazard ratio = 1.1, 0.6 to 1.9, P = 0.810; trivial effect) index injury, or in location. Subsequent injuries were more likely to be contact-based after a non-concussion injury than concussion (odds ratio = 4.6, 1.3 to 16.0; P = 0.017; large effect). There was no difference in subsequent injury severity after lower- (3.4 ±â€¯3.0 missed matches; incidence rate ratio = 1.4, 0.9 to 2.1; P ≤ 0.117; small effect) and upper-limb injuries (3.4 ±â€¯3.1 missed matches; incidence rate ratio = 1.4, 0.9 to 2.2; P = 0.189; small effect) compared to concussion (2.4 ±â€¯2.0 missed matches). CONCLUSIONS: Subsequent injury risk, severity, and location in junior Australian football are similar following concussion compared to non-concussion index injuries, although contact injuries are less likely.

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.

Effect of Running-Induced Fatigue on Tibial Acceleration and the Role of Lower Limb Muscle Strength, Power, and Endurance.

BACKGROUND: High-impact loads have been linked with running injuries. Fatigue has been proposed to increase impact loads, but this relationship has not been rigorously examined, including the associated role of muscle strength, power, and endurance. PURPOSE: This study aimed to investigate the effect of fatigue on impact loading in runners and the role of muscle function in mediating changes in impact loading with fatigue. METHODS: Twenty-eight trained endurance runners performed a fixed-intensity time to exhaustion test at 85% of V̇O 2max . Tibial accelerations were measured using leg-mounted inertial measurement units and sampled every minute until volitional exhaustion. Tests of lower limb muscle strength, power, and endurance included maximal isometric strength (soleus, knee extensors, and knee flexors), single leg hop for distance, and the one leg rise test. Changes in peak tibial acceleration (PTA, g ) were compared between time points throughout the run (0%, 25%, 50%, 75%, and 100%). Associations between the change in PTA and lower limb muscle function tests were assessed (Spearman's rho [ rs ]). RESULTS: PTA increased over the duration of the fatiguing run. Compared with baseline (0%) (mean ± SD, 9.1 g ± 1.6 g ), there was a significant increase at 75% (9.9 g ± 1.7 g , P = 0.001) and 100% (10.1 g ± 1.8 g , P < 0.001), with no change at 25% (9.6 g ± 1.6 g , P = 0.142) or 50% (9.7 g ± 1.7 g , P = 0.053). Relationships between change in PTA and muscle function tests were weak and not statistically significant ( rs = -0.153 to 0.142, all P > 0.05). CONCLUSIONS: Peak axial tibial acceleration increased throughout a fixed-intensity run to exhaustion. The change in PTA was not related to performance in lower limb muscle function tests.

Running-induced fatigue and impact loading in runners: A systematic review and meta-analysis.

This systematic review and meta-analysis aimed to synthesise and clarify the effect of running-induced fatigue on impact loading during running. Eight electronic databases were systematically searched until April 2021. Studies that analysed impact loading over the course of a run, in adult runners free of medical conditions were included. Changes in leg stiffness, vertical stiffness, shock attenuation, peak tibial accelerations, peak ground reaction forces (GRF) and loading rates were extracted. Subgroup analyses were conducted depending on whether participants were required to run to exhaustion. Thirty-six studies were included in the review, 25 were included in the meta-analysis. Leg stiffness decreased with running-induced fatigue (SMD -0.31, 95% CI -0.52, -0.08, moderate evidence). Exhaustive and non-exhaustive subgroups were different for peak tibial acceleration (Chi2 = 3.79, p = 0.05), with limited evidence from exhaustive subgroups showing an increase in peak tibial acceleration with fatigue. Findings for vertical GRF impact peak and peak braking force were conflicting based on exhaustive and non-exhaustive protocols (Chi2 = 3.83, p = 0.05 and Chi2 = 5.10, p = 0.02, respectively). Moderate evidence suggests leg stiffness during running decreases with fatigue. Given the non-linear relationship between leg stiffness and running economy, this may have implications for performance.

The Relationship Between Performance and Injury in Junior Australian Football Athletes.

PURPOSE: Determine the impact of preseason and between-seasons changes in individual physical performance on injury risk in elite junior Australian football players and if injuries sustained during a season impact subsequent-season performance improvement. METHODS: This prospective cohort study assessed individual performance measures (sprint speed, jump, agility, and aerobic endurance) during preseason over 4 consecutive seasons. Injury status (injured/not injured) was tracked weekly to determine the relationship between individual performance and in-season injury occurrence. Mixed models were used to determine the relationship between physical performance and injury, and the effect of injury on physical performance improvement. RESULTS: A total of 206 players played 2 consecutive seasons and were included (17.6 y, 181.9 cm, 75.7 kg). Faster players during preseason experienced higher injury incidence (injuries/season) during that playing season (incidence rate ratio = 0.127; P = .034). Injury incidence was not influenced by between-seasons change in any performance measure. Players injured during their first season maintained their aerobic fitness, which declined in noninjured players (d = 0.39; P = .013). Players who sustained a lower-limb injury during their first season saw smaller improvements in sprint speed than players who did not get injured (d = 0.39; P = .035). CONCLUSION: Faster players experience higher injury incidence than slower players and may require specific prevention interventions. Players who experience a lower-limb injury during the playing season do not improve sprint speed between seasons to the same extent as players who do not get injured, highlighting the need for targeted high-speed running ability development as part of rehabilitation.

The association between Y-balance test scores, injury, and physical performance in elite adolescent Australian footballers.

OBJECTIVES: Identify how modified Lower-Quarter Y-Balance Test (mYBT-LQ) and Upper-Quarter Balance Test (mYBT-UQ) scores relate to injury risk and measures of physical performance in elite adolescent Australian Football (AF) athletes. DESIGN: Prospective cohort study. METHODS: Pre-season mYBT-LQ, mYBT-UQ, and physical performance measures (speed, jump height, and agility) were obtained in 257 elite adolescent male AF athletes. Injury status was tracked across the 18-game season to determine the relationship between mYBT scores and injury risk based on time-to-event analysis. Cross-sectional analysis of mYBT-LQ scores and performance measures determined the relationships between these variables. RESULTS: There were no significant associations between injury risk and any single mYBT parameter. However, athletes with high posteromedial asymmetry and good agility performance (top 25% of the cohort) had moderately increased injury risk with and tended to without a previous injury history (Hazard Ratio = 3.26 [95% Confidence Interval: 1.01, 10.54; p = 0.048] and 2.69 [95% Confidence Interval = 0.92, 7.82; p = 0.069], respectively). There were significant correlations between faster agility times and higher composite limb-length normalised mYBT-LQ (r = -0.210; CI = -0.324, -0.090), limb-length normalised average posteromedial reach score (r = -0.227; CI = -0.340, -0.108), and limb-length normalised average posterolateral reach score (r = -0.250: CI = -0.361, -0.132). CONCLUSION: In isolation, the mYBT is not useful for identifying injury risk in junior AF athletes, and only small correlations between mYBT-LQ and physical performance variables were identified. However, high mYBT-LQ posteromedial asymmetry is associated with increased injury risk for athletes with good agility performance. This should be considered within athlete preparation programs.

Relationship Between Movement Quality and Physical Performance in Elite Adolescent Australian Football Players.

ABSTRACT: Bennett, H, Fuller, J, Milanese, S, Jones, S, Moore, E, and Chalmers, S. The relationship between movement quality and physical performance in elite adolescent Australian football players. J Strength Cond Res 36(10): 2824-2829, 2022-The assessment of movement quality is commonplace in competitive sport to profile injury risk and guide exercise prescription. However, the relationship between movement quality scores and physical performance measures is unclear. Moreover, whether improvements in these measures are associated remain unknown. Over a 4-year period, 918 individual elite adolescent Australian Rules Footballers completed the Functional Movement Screen (FMS) and physical performance testing (5- and 20-m sprint, vertical jump, planned agility, and 20-m shuttle run test), allowing the analysis of relationships between FMS parameters and performance measures. In addition, 235 athletes completed testing over 2 consecutive years, allowing the analysis of relationships between changes in these outcomes. Small associations were observed between FMS composite score, hurdle step performance, in-line lunge performance, trunk stability push-up performance, rotary stability, and measures of speed, power, agility, and aerobic fitness (ρ = 0.071-0.238). Across consecutive seasons, significant improvements were observed in the deep squat subtest ( d = 0.21), FMS composite score ( d = 0.17), and 5- ( d = 0.16) and 20-m sprint times ( d = 0.39). A negative association between change in rotary stability and change in jump height (ρ = -0.236) from one season to the next was detected. Results suggest FMS scores have limited relationships with measures of performance in footballers. To optimize athletic performance, once acceptable movement capabilities have been established, training should not prioritize improving movement quality over improvements in strength, power, and change of direction ability.

Thermal Strain During Open-Water Swimming Competition in Warm Water Environments.

Open-water swim racing in warm water is associated with significant physiological strain. However, existing international policy that governs safe participation during competition relies only on a fixed water temperature threshold for event cancellation and has an unclear biophysical rationale. The current policy does not factor other environmental factors or race distance, nor provide a stratification of risk (low, moderate, high, or extreme) prior to the threshold for cancellation. Therefore, the primary aim of this Perspectives article is to highlight considerations for the development of modernized warm-water competition policies. We highlight current accounts (or lack thereof) of thermal strain, cooling interventions, and performance in warm-water swimming and opportunities for advancement of knowledge. Further work is needed that systematically evaluate real-world thermal strain and performance during warm water competition (alongside reports of environmental conditions), novel preparatory strategies, and in-race cooling strategies. This could ultimately form a basis for future development of modernized policies for athlete cohorts that stratifies risk and mitigation strategies according to important environmental factors and race-specific factors (distance).

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.

Considerations for the development of extreme heat policies in sport and exercise.

We detail key considerations for the development of extreme heat policies in sport and exercise. Policies should account for the four environmental parameters (ambient temperature, humidity, air velocity, and mean radiant temperature) and two personal (activity and clothing) parameters that determine the prevailing thermoregulatory strain during exercise in the heat. Considerations for how to measure environmental stress and convey the level of risk are discussed. Finally, we highlight the need to include feasible cooling strategies that are relevant for the prevailing environmental conditions.

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.

Brief in-play cooling breaks reduce thermal strain during football in hot conditions.

OBJECTIVES: The study examined if three feasible strategies involving additional in-play cooling periods attenuate the core (rectal) temperature rise during simulated football matches. DESIGN: Four counterbalanced experimental trials in an environmental chamber set to 35 °C ambient temperature, 55% relative humidity, and 30 °C WBGT. METHODS: Twelve healthy well-trained football players completed a regular simulated match (REG), regular simulated match with additional 3-min cooling periods at the 30-min mark of each half inclusive of chilled water consumption (COOLwater), regular simulated match with additional 3-min cooling periods at the 30-min mark of each half inclusive of chilled water consumption and the application of an ice towel around the neck (COOLtowel), regular simulated match with an extended (+5 min; total of 20-min) half-time break (HTextended). RESULTS: The difference in rectal temperature change was significantly lower in the COOLwater (-0.25 °C), COOLtowel (-0.28 °C), and HTextended (-0.21 °C) trials in comparison to the REG (all p < 0.05). Exercising heart rate and session rating of perceived exertion was lower in the COOLwater (-13 bpm; -1.4 au), COOLtowel (-10 bpm; -1.3 au), and HTextended (-8 bpm; -0.9 au) trials in comparison to the REG trial (all p < 0.05). The cooling interventions did not significantly change skin temperature or thermal sensation in comparison to the REG (all p > 0.05). CONCLUSIONS: All three cooling interventions attenuated core body thermal strain during simulated matches. The laboratory-based study supports the use of brief in-play cooling periods as a means to attenuate the rise in core temperature during matches in hot and humid conditions.

Factors Influencing the Relationship Between the Functional Movement Screen and Injury Risk in Sporting Populations: A Systematic Review and Meta-analysis.

BACKGROUND: Studies investigating the association between the Functional Movement Screen (FMS) and sports injury risk have reported mixed results across a range of athlete populations. OBJECTIVES: The purpose of this systematic review was to identify whether athlete age, sex, sport type, injury definition and mechanism contribute to the variable findings. STUDY DESIGN: Systematic review and meta-analysis. METHODS: A systematic search was conducted in October 2018 using PubMed, EBSCOhost, Scopus, EmBase and Web of Science databases. Studies were included if they were peer reviewed and published in English language, included athletes from any competition level, performed the FMS at baseline to determine risk groups based on FMS composite score, asymmetry or pain, and prospectively observed injury incidence during training and competition. Study eligibility assessment and data extraction was performed by two reviewers. Random effects meta-analyses were used to determine odds ratio (OR), sensitivity and specificity with 95% confidence intervals. Sub-group analyses were based on athlete age, sex, sport type, injury definition, and injury mechanism. RESULTS: Twenty-nine studies were included in the FMS composite score meta-analysis. There was a smaller effect for junior (OR = 1.03 [0.67-1.59]; p = 0.881) compared to senior athletes (OR = 1.80 [1.17-2.78]; p = 0.008) and for male (OR = 1.79 [1.08-2.96]; p = 0.024) compared to female (OR = 1.92 [0.43-8.56]; p = 0.392) athletes. FMS composite scores were most likely to be associated with increased injury risk in rugby (OR = 5.92 [1.67-20.92]; p = 0.006), and to a lesser extent American football (OR = 4.41 [0.94-20.61]; p = 0.059) and ice hockey (OR = 3.70 [0.89-15.42]; p = 0.072), compared to other sports. Specificity values were higher than sensitivity values for FMS composite score. Eleven studies were included in the FMS asymmetry meta-analysis with insufficient study numbers to generate sport type subgroups. There was a larger effect for senior (OR = 1.78 [1.16-2.73]; p = 0.008) compared to junior athletes (OR = 1.21 [0.75-1.96]; p = 0.432). Sensitivity values were higher than specificity values for FMS asymmetry. For all FMS outcomes, there were minimal differences across injury definitions and mechanisms. Only four studies provided information about FMS pain and injury risk. There was a smaller effect for senior athletes (OR = 1.28 [0.33-4.96]; p = 0.723) compared to junior athletes (OR = 1.71 [1.16-2.50]; p = 0.006). Specificity values were higher than sensitivity values for FMS pain. CONCLUSION: Athlete age, sex and sport type explained some of the variable findings of FMS prospective injury-risk studies. FMS composite scores and asymmetry were more useful for estimating injury risk in senior compared to junior athletes. Effect sizes tended to be small except for FMS composite scores in rugby, ice hockey and American football athletes. PROTOCOL REGISTRATION: CRD42018092916.