Balance and injury in elite Australian footballers

This project measured pre-season balance ability and determined its relationship to knee and ankle ligament injuries during the season for professional Australian footballers. The balance test involved the players stepping onto a foam balance mat on top of a force plate and maintaining single limb balance. Throughout the playing season, injuries were monitored. The results from two hundred and ten players participating in this project were analysed. During the 2003 season, 8 % (17 out of 210) sustained a knee ligament injury and 10 % (21 out of 210) sustained an ankle ligament injury. Multivariate analysis revealed that pre-season balance ability was a significant independent predictor of ankle ligament injury. Players with low balance ability had at least twice as many ankle ligaments injuries as those with average or good balance ability. Balance ability was not a significant predictor of knee ligament injuries. The height of the players was the only significant independent predictor of knee ligament injuries. Low pre-season balance ability was associated with an increased risk of ankle ligament injury. A modifiable injury risk factor has been identified. Research is now required to determine the optimal training regime to enhance balance ability and whether this translates to a reduction in the incidence of ankle injuries.     

Individual and combined effects of acute and chronic running loads on injury risk in elite Australian footballers

A model that takes into account the current workload, and the workload the athlete has been prepared for, as an acute:chronic workload ratio has been previously used as a novel way to monitor training load and injury risk. Fifty‐nine elite Australian football players from one club participated in this 2‐year study. Global Positioning System technology was used to provide information on running workloads of players. An injury was defined as any non‐contact “time‐loss” injury. One‐week (acute), along with 4‐week (chronic) workloads were calculated for a range of variables. The size of the acute workload in relation to the chronic workload was calculated as an acute:chronic workload ratio. An acute:chronic workload ratio of >2.0 for total distance during the in‐season was associated with a 5 to 8‐fold greater injury risk in the current [relative risk (RR) = 8.65, P = 0.001] and subsequent week (RR = 5.49, P = 0.016). Players with a high‐speed distance acute:chronic workload ratio of >2.0 were 5–11 times more likely to sustain an injury in the current (RR = 11.62, P = 0.006) and subsequent week (RR = 5.10, P = 0.014). These findings demonstrate that sharp increases in running workload increase the likelihood of injury in both the week the workload is performed, and the subsequent week.     

High risk of new knee injury in elite footballers with previous anterior cruciate ligament injury

Background

Anterior cruciate ligament (ACL) injury is a severe event for a footballer, but it is unclear if the knee injury rate is higher on returning to football after ACL injury.

Objective

To study the risk of knee injury in elite footballers with a history of ACL injury compared with those without.

Method

The Swedish male professional league (310 players) was studied during 2001. Players with a history of ACL injury at the study start were identified. Exposure to football and all time loss injuries during the season were recorded prospectively.

Results

Twenty four players (8%) had a history of 28 ACL injuries in 27 knees (one rerupture). These players had a higher incidence of new knee injury of any type than the players without ACL injury (mean (SD) 4.2 (3.7) v 1.0 (0.7) injuries per 1000 hours, p  =  0.02). The risk of suffering a knee overuse injury was significantly higher regardless of whether the player (relative risk 4.8, 95% confidence interval 2.0 to 11.2) or the knee (relative risk 7.9, 95% confidence interval 3.4 to 18.5) was used as the unit of analysis. No interactive effects of age or any other anthropometric data were seen.

Conclusion

The risk of new knee injury, especially overuse injury, was significantly increased on return to elite football after ACL injury regardless of whether the player or the knee was used as the unit of analysis.     

Intrinsic and extrinsic risk factors for anterior cruciate ligament injury in Australian footballers

The aim of this study was to examine the interaction between intrinsic (player-related) and extrinsic (environment-related) variables as risk factors for anterior cruciate ligament injury in Australian football. Between 1992 and 1999, 100,820 player-match exposures were analyzed for risk of anterior cruciate ligament injury using logistic regression analysis. There were 63 surgically proven noncontact anterior cruciate ligament injuries. The strongest risk factors were a player history of anterior cruciate ligament reconstruction either in the previous 12 months (relative risk [RR], 11.33; 95% confidence interval [CI], 4.02 to 31.91) or before the previous 12 months (RR, 4.44; 95% CI, 2.46 to 8.01). Weather conditions that were associated with dry field conditions--high water evaporation in the month before the match (RR, 2.55; 95% CI, 1.44 to 4.52) and low rainfall in the year before the match (RR, 2.87; 95% CI, 1.30 to 6.32)--were also significantly associated with these injuries. The increased risk of injury in the first 12 months after reconstruction was associated with the reconstructed knee, whereas after 12 months there was an even distribution of new injuries to the reconstructed knee and contralateral knee. A history of anterior cruciate ligament reconstruction is a risk factor for further injury. Weather conditions of high evaporation and low rainfall before matches are associated with noncontact anterior cruciate ligament injury.     

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

ObjectivesIdentify 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.DesignProspective cohort study.MethodsPre-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.ResultsThere 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).ConclusionIn 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.     

Kicking footedness and movement discrimination by elite Australian Rules footballers.

Kicking a football accurately with a certain velocity over a desired distance is dependent upon the speed of the kicking foot and the quality of contact between the foot and ball. Control of the swinging lower leg is critical to these factors and the overall performance of the kick, and this was assessed in 20 Australian Football League players. Assessment of movement extent discrimination of the swinging leg was made while standing on the other leg. An automated device accurately set a stop plate to five different positions and each subject was asked to swing the leg to the plate, and make a non-visual judgment of the movement extent. Forty forward and forty backward swings of each leg were assessed, and based on a subject's responses, non-parametric signal detection analysis resulted in a movement extent discrimination score. For left leg performance, coach ratings of overall kicking ability were correlated with movement discrimination ability. Left-foot kickers (0.83) had a higher movement discrimination score than right-foot kickers (0.77), and had a significantly higher score on their dominant side, whereas right-footers had no left-right side difference. Rating of kicking ability by coaches also reflected this difference between the dominant leg performance of left- and right-footers. These data showed left-foot kickers to have higher movement discrimination ability with their dominant leg, and this may be related to their on-field kicking ability.     

DHA-rich fish oil lowers heart rate during submaximal exercise in elite Australian Rules footballers

Omega-3 fatty acids (n-3) can improve cardiovascular (CV) function. This study examined the effects of n-3 on endurance performance, recovery and CV risk factors in elite Australian Rules football players. 25 players were randomised, double-blind, to 6 g/day of docosahexaenoic acid (DHA)-rich fish oil (FO; n = 12) or sunflower oil (SO; n = 13) during 5 weeks of training. At baseline erythrocyte n-3 content, resting blood pressure (BP), fasting serum triglycerides (TG) and heart rate (HR) during treadmill running at 10 km/h were assessed. Two treadmill runs (T1 and T2) to exhaustion, separated by 5 min, were then performed at the average speed for a recent 2200 m time-trial. After 5 weeks, erythrocyte n-3 increased (FO 3.8 ± 0.6%, SO 0.6 ± 0.3%; P < 0.001) while TG (FO ?0.32 ± 0.09 mmol l^?1, SO 0.08 ± 0.05 mmol l^?1; P < 0.001), diastolic BP (FO 1.3 ± 1.3 mmHg, SO 6.8 ± 1.7 mmHg; P = 0.04) and HR during submaximal exercise (FO ?7.8 ± 2.3 beats min^?1, SO ?1.9 ± 1.9 beats min^?1; P = 0.03) decreased in FO compared with SO. Time to exhaustion (TTE) during T1 increased by Week 5 (FO 10.2 ± 2.2%, SO 17.3 ± 4.3%; P < 0.001 for time). Recovery (TTE for T2 as % T1) decreased in both groups (FO, ?3.4 ± 4.5%, SO ?8.8 ± 3.9%; P = 0.05 for time). We conclude that 5 weeks of supplementation with FO improved CV function and reduced CV risk factors, but did not improve endurance performance or recovery in elite Australian Rules footballers.     

Reduced death rates of elite Australian Rules footballers compared to age-matched general population

ObjectivesTo determine age-matched death rates of current and retired elite male Australian football players (Australian and/or Victorian Football League) with the general population.DesignAnalysis of publicly-available birth, debut and death data for all Australian Victorian Football/Victorian Football League players who debuted prior to (and were still alive at) the start of 1971 or debuted 1971–2020.MethodsWikipedia was used to source the dates of death (or record that the player was alive in 2021) for the cohort. New players became part of the cohort for analysis on debut and existing cohort members left it at death. Actual death rates (per year and per decade) were then compared to expected deaths, based on age-specific population death rates.ResultsThere were 5400 players and ex-players in the cohort at the start of 1971 (average age 47.3) and a further 4532 players debuted between 1971 and 2020 inclusive (a total of 9932 players). The expected deaths for the cohort in this 50-year period were 4955, but only 3914 deaths occurred (Standardized Mortality Ratio 0.79, 95 %CI 0.76–0.82). For younger members of the cohort (age <50) the discrepancy between expected (222) and actual (98) deaths was also significant (Standardized Mortality Ratio 0.44, 95 %CI 0.35–0.56).ConclusionsWe conclude that the death rates of elite male Australian footballers are lower than the reference general population, similar to other studies of elite athletes. Some of this may be explained by “healthy cohort” selection bias, a limitation which affects almost all studies in this genre.     

The effect of interstate travel on sleep patterns of elite Australian Rules footballers

The purpose of the current study was to examine the effect of interstate air travel on the quality and quantity of sleep in elite Australian Rules football players. Ten elite male athletes, who were members of a Western Australian-based Australian Football League (AFL) team, participated in the study. Sleep pattern was assessed by measuring sleep duration (SLD), sleep efficiency (SE), number of wakings (NW) and total wake time after sleep onset (WT) using a wrist-worn actigraph. Subjective sleep quality (SQ) was assessed using a scale of sleep rating. Throughout the 2002 AFL season, measurements were obtained on the night before (N1), the night of (N2) and the night after (N3) home and away games. Baseline measurements were obtained from five consecutive non-game nights. Compared to baseline, SLD on N1 was increased when home and away (by 51 and 105 mins respectively, p<0.05), while all other measures of sleep pattern were unchanged. On N2, SLD was decreased to a similar degree whether home or away (by 68 and 64 mins respectively, p<0.05), while all other measures of sleep pattern were unchanged. By N3 all measures of sleep pattern had returned to baseline values. Relative to baseline, perception of SQ was worst on N2 of a home game. This study has shown that interstate travel by elite AFL players has no adverse effects on sleep pattern on the night before a game.     

Identifying high risk loading conditions for in-season injury in elite Australian football players

Objectives

To examine different timeframes for calculating acute to chronic workload ratio (ACWR) and whether this variable is associated with intrinsic injury risk in elite Australian football players.

Isokinetic strength testing does not predict hamstring injury in Australian Rules footballers

OBJECTIVE: To determine the relation of hamstring and quadriceps muscle strength and imbalance to hamstring injury using a prospective observational cohort study METHOD: A total of 102 senior male Australian Rules footballers aged 22.2 (3.6) years were tested at the start of a football season. Maximum voluntary concentric and eccentric torque of the hamstring and quadriceps muscles of both legs was assessed using a Kin-Com isokinetic dynamometer at angular velocities of 60 and 180 degrees/second. Twelve (11.8%) players sustained clinically diagnosed hamstring strains which caused them to miss one or more matches over the ensuing season. RESULTS: There were no significant differences for any of the isokinetic variables comparing the injured and non-injured legs in players with unilateral hamstring strains (n=9). Neither the injured nor the non-injured leg of injured players differed from the mean of left and right legs in non-injured players for any isokinetic variable. The hamstring to opposite hamstring ratios also did not differ between injured and non-injured players. A hamstring to opposite hamstring ratio of less than 0.90 and a hamstring to quadriceps ratio of less than 0.60 were not associated with an increased risk of hamstring injury. A significantly greater percentage of players who sustained a hamstring strain reported a history of hamstring strain compared with non-injured players (p=0.02). However, this was not related to muscle weakness or imbalance. CONCLUSIONS: Isokinetic muscle strength testing was not able to directly discriminate Australian Rules football players at risk for a hamstring injury.


     

Prevalence of headache in Australian footballers

Methods: A prospective questionnaire based survey was performed on elite Australian footballers participating in a national competition. The survey was designed to assess the prevalence and risk factors for headache using standardised International Headache Society (HIS) criteria. Headache prevalence was compared with that of an age and sex matched community control population.

Results: A total of 160 questionnaires were analysed. Headaches were reported by 80% of subjects, with 49% of respondents reporting headaches during competitive match play and 60% during training. There was no significant difference between the footballers and the community sample in the number of headaches ever; however, they did report more headaches in the three months before the survey —that is, during the competitive playing season. In the footballers, 22% of headaches conformed to the strict IHS definition of migraine headaches. When the relaxed definition of "footballer's migraine" was used, 34% of headaches met these criteria. Footballers were at significantly increased risk of footballer's migraine than community controls.

Conclusions: Headaches are common in Australian footballers, and the prevalence of migraine is increased in relation to community prevalence studies. Furthermore, the strict IHS criteria may not adequately identify the specific subtype of football related headache. This finding has important implications in the management of headache in this setting.

     

Lower-limb injury in elite Australian football: A narrative review of kinanthropometric and physical risk factors

ObjectiveThis review aims to provide a succinct and critical analysis of the current physical and mechanical demands of elite Australian football while examining lower-limb injury and the associated physical and kinanthropometric risk factors.MethodsMEDLINE, PubMed, Web of Science and SPORTSDiscus electronic databases were searched for studies that investigated the playing demands, injury trends, and physical and kinanthropometric injury risk factors of elite Australian football. Articles from similar team sports including soccer and rugby (union and league) were also included.ResultsWhile the physical demands of elite AF have steadied over the past decade, injury rates continue to rise with more than two-thirds of all injuries affecting the lower-limbs. Body composition and musculoskeletal morphological assessments are regularly adopted in many sporting settings with current research suggesting high and low body mass are both associated with heightened injury risk. However, more extensive investigations are required to determine whether the proportions of muscle and fat are linked. Repeated assessment of musculoskeletal morphology may also provide further insight into stress fracture rates.ConclusionsWhile kinanthropometric and physical attributes are highly valued within elite sporting environments, establishing a deeper connection with injury may provide practitioners with more insight into current injury trends.     

Performance and anthropometric characteristics of prospective elite junior Australian footballers: A case study in one junior team

The aim of the study was to compare anthropometric and physical performance data of players who were selected for a Victorian elite junior U18 Australian rules football squad. Prior to the selection of the final training squad, 54 players were assessed using a battery of standard anthropometric and physical performance tests. Multivariate analysis (MANOVA) showed significant (p<0.05) differences between selected and non-selected players when height, mass, 20-m sprint, agility and vertical jump height were considered collectively. Univariate analysis revealed that the vertical jump was the only significant (p<0.05) individual test and a near significant trend (p=0.07) for height differentiating between selected and non-selected players with medium effect sizes for all other tests except endurance. In this elite junior football squad, physical characteristics can be observed that discriminate between players selected and non-selected, and demonstrates the value of physical fitness testing within the talent identification process of junior (16-18 years) players for squad and/or team selection. Based on MANOVA results, the findings from this study suggest team selection appeared to be related to a generally higher performance across the range of tests. Further, age was not a confounding variable as players selected tended to be younger than those non-selected. These findings reflect the general consensus that, in state-based junior competition, there is evidence of promoting overall player development, selecting those who are generally able to fulfil a range of positions and selecting players on their potential.     

The effect of interstate travel on the sleep patterns and performance of elite Australian Rules footballers.

This study examined the effect of interstate travel on sleep patterns and game performance of elite Australian Rules footballers. Nineteen members of a Western Australian-based Australian Football League team participated in the study during the 2004 season. Sleep was assessed on the night before home and away games by measuring sleep duration (SLD), sleep efficiency (SLE), wake time (WT) and number of wakings (NW) via actigraphy. Subjective sleep quality was assessed using a sleep rating (SR) scale. Baseline sleep measurements were obtained over four consecutive non-game nights. Game performance was assessed using a coach's rating (CR) scale and impact ranking (IR) and by player statistics including frequency of possessions (P) and frequency of possessions and team assists (PTA). Compared to baseline, SLD was greater on the nights before home and away games (by 48 and 39 min, respectively, p<0.05). Other sleep measures were unchanged. Sleep rating was poorer before away than home games (p<0.05). CR and IR were greater during home than away games (p<0.05). All other measures of performance were similar at home and away. These results show that prior interstate travel has minimal effect on sleep quality and game performance in elite footballers.     

Relation between lower limb comfort and performance in elite footballers

ObjectivesSuccesses of the professional athlete as individuals and team, across codes of football are contingent upon performance measures. The aim of the study was to examine associations between comfort and performance.DesignProspective measures of lower limb comfort and coach rating performance criterion. Comfort and performance associations were described using Pearson’s correlation coefficient (r) or the R square value from the regression estimate.SettingTwo professional football codes in Australia.Participants79 professional footballers were followed for one football season, a total of 1724 player weeks.Main Outcome MeasuresStudy hypothesis was poor lower limb comfort is negatively correlated with good match day rated performance. Aspects of validity and responsiveness to change tested the hypothesis that lower limb comfort, affects rated performance. A validated lower limb comfort index (LLCI) was used to test comfort. Rated performance was evaluated by subjective rating criterion of experienced team coaches.ResultsPoor lower limb comfort and good match day ratings were not well correlated (R² = 0.25, P≤0.001) and usual-high comfort was correlated with usual-good performance (R² = 0.69, P≤0.001).ConclusionsLower limb comfort may be a sensitive measure of rated performance in football. The LLCI is the first measurement tool to show association between comfort and rated performance.