Professional Australian Football Research Articles

Effects ofStricter Management Guidelines on Return-to-Competition Timeframes Following Concussion in Professional Australian Rules Football: An Exploratory Analysis.

BackgroundManagement of concussion remains a serious issue for professional sports, particularly with the growing knowledge on the consequences of repetitive concussion. One primary concern is the subjective assessment of recovery that dictates the time until a concussed athlete is returned-to-competition. In response to this concern, the Australian Football League (AFL) changed its policy in 2020 such that medical clearance for return-to-competition was extended from 1 day, to a minimum of 5 days, prior to the next scheduled match.ObjectiveWe sought to explore the impact of the AFL policy change by asking whether time to return-to-competition after concussion was increased in the 2020 season relative to previous years.MethodsRetrospective data on injury and return-to-competition were sourced from publicly available tables published by the AFL. Our primary exploration compared the number of matches missed and the number of days missed in concussed players across 2017–2020 inclusive, with secondary exploration analysing the proportion of players returning to play 12 days or longer.ResultsAnalysis of data from 166 concussed players revealed no increase in the number of matches missed in 2020 relative to previous years as would have been expected from an extended recovery protocol. Comparing 2020 relative to 2017–2019, we found that there was an overall moderate reduction in median time to return-to-competition (RTC) in 2020 (10 vs 13 days, respectively d = − 0.345) and a significant reduction in players taking more than 12 days to RTC (p = 0.046).ConclusionThis exploratory study demonstrates that clubs may not have followed policy change around concussion management designed to increase time to RTC. Ongoing auditing is required to ensure player clearance meets policy goals, highlighting the need for objective measures for RTC after concussion.

A Qualitative Investigation of Factors Influencing the Dietary Intakes of Professional Australian Football Players.

(1) Background: Many professional Australian Football (AF) players do not meet recommended sports nutrition guidelines despite having access to nutrition advice. There are a range of factors that can influence players′ ability to meet their nutrition goals and awareness of the barriers players face is essential to ensure that dietary advice translates into practice. Therefore, this qualitative research study aimed to explore the factors influencing AF players’ dietary intakes and food choice. (2) Methods: Semi-structured interviews were conducted with twelve professional male AF players. (3) Results: Less experienced players restricted their carbohydrate intake to meet body composition goals, particularly during preseason and surrounding body composition assessment. During the competition season players had a greater focus on performance and placed more emphasis on carbohydrate intake in the lead up to matches. Players felt nutrition goals were easier to achieve when dietary choices were supported by their families and peers. One-on-one consultations provided by a sports dietitian were players′ preferred mode of nutrition intervention. Individualized nutrition advice is required for less experienced AF players who may be vulnerable to unsustainable dietary habits. Experienced AF players can support junior teammates by promoting positive team culture related to body composition, nutrition and performance.

What a ‘Boo’ Can Do: Adam Goodes, Discrimination, and Norm (R)evolution

ABSTRACT In this commentary I evaluate what McGowan’s project would conclude with respect to the treatment of professional Australian Football League player Adam Goodes, who was incessantly ‘booed’ by crowds for the final two years of his career. Analysing Goodes’ case in light of McGowan’s argument leads me to two observations. First, McGowan’s norm-enactment approach is incredibly useful because it explains how words like ‘boo’ (with unstable meaning) can constitute actionable discrimination. Second, however, I wonder if a narrow focus on whether such speech is legally actionable might encourage an overestimation of the power of laws to shepherd new g-norms into social practices.

Comparisons of Daily Energy Intake vs. Expenditure Using the GeneActiv Accelerometer in Elite Australian Football Athletes.

Salagaras, BS, Mackenzie-Shalders, KL, Nelson, MJ, Fraysse, F, Wycherley, TP, Slater, GJ, McLellan, C, Kumar, K, and Coffey, VG. Comparisons of daily energy intake vs. expenditure using the GeneActiv accelerometer in elite Australian Football athletes. J Strength Cond Res 35(5): 1273-1278, 2021-To assess validity of the GeneActiv accelerometer for use within an athlete population and compare energy expenditure (EE) with energy and macronutrient intake of elite Australian Football athletes during a competition week. The GeneActiv was first assessed for utility during high-intensity exercise with indirect calorimetry. Thereafter, 14 professional Australian Football athletes (age, 24 ± 4 [SD] y; height, 1.87 ± 0.08 m; body mass, 86 ± 10 kg) wore the accelerometer and had dietary intake assessed via dietitian-led 24-hour recalls throughout a continuous 7 days of competition period (including match day). There was a significant relationship between metabolic equivalents and GeneActiv g·min-1 (SEE 1.77 METs; r2 = 0.64; p < 0.0001). Across the in-season week a significant difference only occurred on days 3 and 4 (day 3: energy intake [EI] EI 137 ± 31 kJ·kg-1·d-1; 11,763 ± 2,646 kJ·d-1 and EE: 186 ± 14 kJ·kg-1·d-1; 16,018 ± 1973 kJ·d-1; p < 0.05; d = -1.4; day 4: EI: 179 ± 44 kJ·kg-1·d-1, 15,413 ± 3,960 kJ·d-1 and EE: 225 ± 42 kJ·kg-1·d-1; 19,313 ± 3,072 kJ·d-1; d = -0.7). Carbohydrate intake (CI) was substantially below current sports nutrition recommendations on 6 of 7 days with deficits ranging from -1 to -7.2 g·kg-1·d-1 (p < 0.05), whereas daily protein and fat intake was adequate. In conclusion, the GeneActiv provides effective estimation of EE during weekly preparation for a professional team sport competition. Australian Footballers attempt to periodize dietary EI to varying daily training loads but fail to match expenditure on higher-training load days. Specific dietary strategies to increase CI may be beneficial to achieve appropriate energy balance and macronutrient distribution, particularly on days where athletes undertake multiple training sessions.

Determination of locomotor qualities in elite Australian Football: A pragmatic approach

ABSTRACT The study examined the utility of surrogate measures of athletic performance to determine locomotor qualities (maximal aerobic velocity and peak velocity) in elite Australian Football (AF). 29 professional AF players undertook aerobic fitness (3km time-trial [TT] and 30–15 Intermittent Fitness Test [30–15 IFT]) and peak velocity (PV; 50 m maximal sprints using 10Hz GPS) assessments in pre-season. Characteristics of TT performance (mean velocity, 500m and 1km splits) were compared with a surrogate for maximal aerobic velocity (MAV; 80% of 30–15 IFT final velocity). PVs derived from sprint tests were compared to those attained in AF matches (10 Hz GPS). Higher Pearson correlations were observed between MAV versus the fastest 500m (r = 0.74) and 1km (r = 0.75) of the 3km TT, but they were not superior to mean velocity (r = 0.72; p ≥ 0.30) which also demonstrated the lowest bias (p ≤ 0.01) and equivalent typical errors (0.16–0.17 m.s−1). Peak velocity was higher across match observations (0.28, CI: ± 0.17 m.s −1, p = 0.017) versus sprint tests. There was no impact of playing position on the determination of locomotor qualities using surrogate measures of locomotor qualities. Locomotor qualities can be determined practically using 10Hz GPS devices during 3km time-trials and competitive matches (assuming appropriate signal quality), without additional fitness assessments.

Outbreak of community-acquired Staphylococcus aureus skin infections in an Australian professional football team

ObjectivesSkin and soft tissue infections commonly affect athletes and can lead to cluster outbreaks if not managed appropriately. We report the findings of an investigation into an outbreak of community-acquired Staphylococcus aureus infection in an Australian professional football team. DesignRetrospective cross-sectional study. MethodsNose, axilla, groin and throat swab were collected from 47 participants. MRSA and MSSA isolates underwent antibiotic susceptibility testing, binary typing and whole genome sequencing. Infection control practitioners (ICPs) investigated the training grounds for risk factors in the transmission of S. aureus. ResultsAlmost half of the participants (n=23, 48.9%) were found to be colonised with MSSA. An outbreak cluster of MRSA ST5 closely related to the fusidic acid-resistant New Zealand NZAK3 clone was identified in a group of four players. MSSA ST15 and MSSA ST291 strains were found to have colonised and spread between two and five players, respectively. All participants were advised to undergo decolonisation treatment consisting of 4% chlorhexidine body wash and mupirocin nasal ointment for ten days. The ICP team identified several unhygienic practices within the club’s shared facilities that may have played a role in the transmission of S. aureus. ConclusionsWe report for the first time a community-associated S. aureus outbreak involving the highly successful fusidic acid-resistant MRSA ST5 clone in a professional football club associated with inadequate hygiene procedures. Management and prevention of S. aureus relies heavily on hygiene education and adherence to personal and environmental hygiene practices and policies.

Associations between refined athlete monitoring measures and individual match performance in professional Australian football

ABSTRACT The purpose of this study was to assess relationships between measures of training load, training response and neuromuscular performance and changes in individual match performance in professional Australian football. Data were collected from 45 professional Australian footballers from one club during the 2019 competition season. External load was measured by GPS technology. Internal load was measured via session rate of perceived exertion (sRPE). Perceptual wellness was measured via pre-training questionnaires (1–5 Likert scale rating of soreness, sleep, fatigue, stress and motivation). Percentage of maximum speed was calculated relative to individual maximum recorded during preseason testing. Rolling derivative training load measures (7-day and 28-day) were calculated. Principal Component Analysis (PCA) identified eight uncorrelated components. PCA factor loadings were used to calculate summed variable covariates and single variables were chosen from components based on practicality and statistical contribution. Associations between covariates and performance were determined via linear Generalised Estimating Equations. Performance was assessed via Player Ratings from a commercial statistics company. Seven-day total distance, IMA event count and sRPE load showed significant positive relationships with performance (18–23% increase in performance z-score). No other covariates displayed significant associations with performance. Individual relative increases in training load within the 7-day period prior to a match may be beneficial for enhancing individual performance.

Data Reduction Approaches to Athlete Monitoring in Professional Australian Football.

To apply data reduction methods to athlete-monitoring measures to address the issue of data overload for practitioners of professional Australian football teams. Data were collected from 45 professional Australian footballers from 1 club during the 2018 Australian Football League season. External load was measured in training and matches by 10-Hz OptimEye S5 and ClearSky T6 GPS units. Internal load was measured via the session rate of perceived exertion method. Perceptual wellness was measured via questionnaires completed before training sessions with players providing a rating (1-5 Likert scale) of muscle soreness, sleep quality, fatigue, stress, and motivation. Percentage of maximum speed was calculated relative to individual maximum velocity recorded during preseason testing. Derivative external training load measures (total daily, weekly, and monthly) were calculated. Principal-component analyses (PCAs) were conducted for Daily and Chronic measures, and components were identified via scree plot inspection (eigenvalue > 1). Components underwent orthogonal rotation with a factor loading redundancy threshold of 0.70. The Daily PCA identified components representing external load, perceived wellness, and internal load. The Chronic PCA identified components representing 28-d speed exposure, 28-d external load, 7-d external load, and 28-d internal load. Perceived soreness did not meet the redundancy threshold. Monitoring player exposure to maximum speed is more appropriate over chronic than short time frames to capture variations in between-matches training-cycle duration. Perceived soreness represents a distinct element of a player's perception of wellness. Summed-variable and single-variable approaches are novel methods of data reduction following PCA of athlete monitoring data.

Utilising one minute and four minute recovery when employing the resistance training contrast method does not negatively affect subsequent jump performance in the presence of concurrent training.

BackgroundLittle is known about contrast training and post-activation performance enhancement (PAPE) in a same day concurrent training model. The aim of the current study was to examine the use of two short duration (1-min and 4-min) recovery periods on drop jump performance in same day concurrently trained athletes.MethodsTen professional Australian Rules footballers (age, 20.6 ± 1.9 yr; height, 184.8 ± 6.9 cm; body mass, 85.8 ± 8.4 kg) completed two resistance training sessions with different PAPE recovery durations; 1-min and 4-min, 1 h following a field-based endurance session. Baseline (pre) drop jumps were compared to post-test maximal drop jumps, performed after each set of three squats (where each participant was encouraged to lift as heavy as they could), to determine changes between 1-min and 4-min recovery periods. Data were analysed by fitting a mixed model (significance was set at P ≤ 0.05). Corrected Hedges’ g standardised effect sizes ±95% confidence limits were calculated using group means ± SDs.ResultsThere were no significant differences between baseline and experimental sets 1, 2 and 3 for reactive strength index (RSI), flight time, and total and relative impulse for either recovery duration. However, for contact time, 1-min baseline was significantly different from set 2 (mean difference; 95% CI [0.029; 0.000–0.057 s], P = 0.047, ES; 95% CI [−0.27; −1.20 to 0.66]). For RSI and flight time, 1-min was significantly higher than 4-min (RSI: 0.367; 0.091 to 0.642, P = 0.010, ES; 95% CI [0.52; −0.37 to 1.42]; flight time: 0.033; 0.003 to 0.063 s, P = 0.027, ES; 95% CI [0.86; −0.06 to 1.78]).DiscussionShort recovery periods of 1-min may be a time-efficient form of prescribing strength-power exercise in contrast loading schemes. Longer recovery periods do not appear to benefit immediate, subsequent performance.

Career Performance Trajectories of Professional Australian Football Players.

To develop position-specific career performance trajectories and determine the age of peak performance of professional Australian Football players. Match performance data (Australian Football League [AFL] Player Rank) were collected for Australian Football players drafted via the AFL National Draft between 1999 and 2015 (N = 207). Players were subdivided into playing positions: forwards (n = 60; age 23 [3]y), defenders (n = 71; age 24 [4]y), midfielders (n = 58; age 24 [4]y), and ruckmen (n = 18; age 24 [3]y). Linear mixed models were fitted to the data to estimate individual career trajectories. Forwards, midfielders, and defenders experienced peak match performance earlier than ruckmen (24-25 vs 27y). Midfielders demonstrated the greatest between-subjects variability (intercept 0.580, age 0.0286) in comparison with ruckmen, who demonstrated the least variability (intercept 0.112, age 0.005) in AFL Player Rank throughout their careers. Age had the greatest influence on the career trajectory of midfielders (β [SE] = 0.226 [0.025], T = 9.10, P < .01) and the least effect on ruckmen (β [SE] = 0.114 [0.049], T = 2.30, P = .02). Professional Australian Football players peak in match performance between 24 and 27years of age with age, having the greatest influence on the match performance of midfielders and the least on ruckmen.

Lumbar Multifidus Muscle Characteristics, Body Composition, and Injury in University Rugby Players.

A smaller lumbar multifidus (LM) muscle was reported to be a strong predictor of lower limb injury in professional Australian Football League players. However, despite the high prevalence of low back pain (LBP) and lower limb injury in rugby players, their LM characteristics have yet to be explored. To (1) examine LM characteristics in male and female university rugby players and their possible associations with LBP and lower limb injury and (2) investigate the relationship between LM characteristics and body composition in this group of athletes. Cross-sectional study. University research center. Thirty-four university rugby players (20 women, 14 men). Ultrasound measurements of LM cross-sectional area (CSA), thickness, and percentage change in thickness during contraction were obtained bilaterally, at the L5-S1 level, in prone and standing positions. Body composition measures were obtained using dual-energy x-ray absorptiometry. Self-reported questionnaires were used to obtain LBP and lower limb injury history. Players who reported LBP in the previous 3 months showed a smaller percentage change in thickness during contraction in the standing position (F = 5.21, P = .03). The LM CSA side-to-side asymmetry (right versus left) was greater in players who reported having a lower limb injury in the previous 12 months (F = 4.98, P = .03). The LM CSA was significantly associated with body composition measurements. A greater percentage change in thickness during contraction was significantly associated with a lower percentage of body fat. The LM echo intensity was strongly associated with the total percentage of body fat and was significantly greater in women. The influence of body composition on LM morphology in athletes cannot be ignored and warrants further investigation. Our findings also provide preliminary evidence of an association among LM morphology, LBP, and lower limb injury in university rugby players.

Effect of Individual Environmental Heat-Stress Variables on Training and Recovery in Professional Team Sport.

Exercise in hot environments increases body temperature and thermoregulatory strain. However, little is known regarding the magnitude of effect that ambient temperature (Ta), relative humidity (RH), and solar radiation individually have on team-sport athletes. To determine the effect of these individual heat-stress variables on team-sport training performance and recovery. Professional Australian Rules Football players (N = 45) undertook 8-wk preseason training producing a total of 579 outdoor field-based observations with Ta, RH, and solar radiation recorded at every training session. External load (distance covered, in m/min; percentage high-speed running [%HSR] >14.4km/h) was collected via a global positioning system. Internal load (ratings of perceived exertion and heart rate) and recovery (subjective ratings of well-being and heart-rate variability [root mean square of the successive differences]) were monitored throughout the training period. Mixed-effects linear models analyzed relationships between variables using standardized regression coefficients. Increased solar-radiation exposure was associated with reduced distance covered (-19.7m/min, P < .001), %HSR (-10%, P < .001) during training and rMSSD 48 h posttraining (-16.9ms, P = .019). Greater RH was associated with decreased %HSR (-3.4%, P = .010) but increased percentage duration >85% HRmax (3.9%, P < .001), ratings of perceived exertion (1.8AU, P < .001), and self-reported stress 24 h posttraining (-0.11AU, P = .002). In contrast, higher Ta was associated with increased distance covered (19.7m/min, P < .001) and %HSR (3.5%, P = .005). The authors show the importance of considering the individual factors contributing to thermal load in isolation for team-sport athletes and that solar radiation and RH reduce work capacity during team-sport training and have the potential to slow recovery between sessions.

The Distribution of Match Activities Relative to the Maximal Mean Intensities in Professional Rugby League and Australian Football.

Johnston, RD, Thornton, HR, Wade, JA, Devlin, P, and Duthie, GM. The distribution of match activities relative to the maximal mean intensities in professional rugby league and Australian football. J Strength Cond Res 36(5): 1360-1366, 2022-This study determined the distribution of distance, impulse, and accelerometer load accumulated at intensities relative to the maximal mean 1-minute peak intensity within professional rugby league and Australian football. Within 26 rugby league (n = 24 athletes) and 18 Australian football (n = 38 athletes) games, athletes wore global navigation satellite system devices (n = 608 match files). One-minute maximal mean values were calculated for each athlete per game for speed (m·minP-1P), accelerometer load (AU·minP-1P), and acceleration (m·sP-2P). Volumes for each parameter were calculated by multiplying by time, specifying total distance, accelerometer load, and impulse. The distribution of intensity of which these variables were performed relative to the maximal mean was calculated, with percentages ranging from 0-110%, separated into 10% thresholds. Linear mixed models determined whether the distribution of activities within each threshold varied, and positional differences. Effects were described using standardized effect sizes (ESs), and magnitude-based decisions. Across both sports, the distribution of activity (%) largely reduced the closer to the maximal mean 1-minute peak and was highest at ∼60% of the maximal mean peak. When compared with Australian football, a higher percentage of total distance was accumulated at higher intensities (70-80% and 100-110%) for rugby league (ES range = 0.82-0.87), with similar, yet larger differences for accelerometer load >80% (0.78-1.07) and impulse >60% (1.00-2.26). These findings provide information of the volume of activities performed relative to the mean maximal 1-minute peak period, which may assist in the prescription of training.

Phases of match-play in professional Australian Football: Distribution of physical and technical performance

ABSTRACT The current study aimed to describe the distribution of physical and technical performance during the different phases of play in professional Australian Football. The phases of play (offence, defence, contested play, umpire stoppages, set shots and goal resets) were manually coded from video footage for a single team competing in 18 matches in the Australian Football League. Measures of physical performance including total distance (m), average speed (m · min−1), low-speed running (LSR, <14.4 km h−1), high-speed running (HSR, >14.4 km h−1), accelerations (2.78 m · s−2) and decelerations (−2.78 m · s−2) were derived from each phase of play via global positioning system (GPS) devices. Technical skill data including tackles, handballs and kicks were obtained from a commercial statistics provider and derived from each phase of play. Linear mixed-effects models and effect sizes were used to assess and reflect the differences in physical and technical performance between the six phases of play. Activity and recovery cycles, defined as periods where the ball was in or out of play were also described using mean and 95% confidence intervals. The analysis showed that several similarities existed between offence and defence for physical performance metrics. Contested play involved the highest total distance, LSR, accelerations, decelerations and tackles compared to all other phases. Offence and defence involved the highest average speed and HSR running distances. Handballs and kicks were highest during offence, while tackles were highest during contested play, followed by defence. Activity and recovery cycles involved mean durations of ~110 and ~39 s and average speeds of ~160 and ~84 m · min−1, respectively. The integration of video, GPS and technical skill data can be used to investigate specific phases of Australian Football match-play and subsequently guide match analysis and training design.

Assessing the nutrition knowledge of professional female Australian football (AFLW) athletes

ABSTRACT Nutrition education in professional sport may improve athletes’ nutrition knowledge (NK), self-efficacy and food choices. Understanding athletes’ NK can inform development of tailored nutrition education programs. To enhance health and performance, athletes’ dietary intakes must meet their energy and nutritional needs and NK has been identified as a modifiable determinant of dietary intake. This study aimed to assess the NK of Australian football league women’s (AFLW) athletes to provide recommendations for possible dietetic intervention. AFLW athletes (n = 26) were recruited from one Victorian football club. NK was assessed using the validated online Nutrition for Sport Knowledge Questionnaire. AFLW athletes scored ‘average’ overall NK (score: 45.1 ± 12.5, mean accuracy: 50.6 ± 14%). Athletes demonstrated better knowledge in alcohol (5.6 ± 1.9, mean accuracy: 70 ± 23%), macronutrients (18.2 ± 5.0, mean accuracy: 60 ± 17%) and weight management subsections (7.3 ± 2.2, mean accuracy: 57 ± 17%). Athletes performed poorly in the supplements subsection (3.2 ± 2.0, mean accuracy: 23 ± 14%). This study assessed the NK of AFLW athletes and found athletes had average NK, with room for improvement particularly regarding supplement knowledge. Future research should assess the efficacy of online and group education to improve athletes’ NK and dietary intake.

An Investigation of Factors Associated With Head Impact Exposure in Professional Male and Female Australian Football Players

Background: Exposure to head acceleration events (HAEs) has been associated with player sex, player position, and player experience in North American football, ice hockey, and lacrosse. Little is known of these factors in professional Australian football. Video analysis allows HAE verification and characterization of important determinants of injury. Purpose: To characterize verified HAEs in the nonhelmeted contact sport of professional Australian football and investigate the association of sex, player position, and player experience with HAE frequency and magnitude. Study Design: Descriptive epidemiology study. Methods: Professional Australian football players wore a nonhelmeted accelerometer for 1 match, with data collected across 14 matches. HAEs with peak linear accelerations (PLAs) ≥30g were verified with match video. Verified HAEs were summarized by frequency and median PLA and compared between the sexes, player position, and player experience. Characterization of match-related situations of verified HAEs was conducted, and the head impact rate per skill execution was calculated. Results: 92 male and 118 female players were recruited during the 2017 season. Male players sustained more HAEs (median, 1; IQR, 0-2) than female players (median, 0; IQR, 0-1; P = .007) during a match. The maximum PLAs incurred during a match were significantly higher in male players (median, 61.8g; IQR, 40.5-87.1) compared with female players (median, 44.5g; IQR, 33.6-74.8; P = .032). Neither player position nor experience was associated with HAE frequency. Of all verified HAEs, 52% (n = 110) occurred when neither team had possession of the football, and 46% (n = 98) were caused by contact from another player attempting to gain possession of the football. A subset of HAEs (n = 12; 5.7%) resulted in players seeking medical aid and/or being removed from the match (median PLA, 58.8g; IQR, 34.0-89.0), with 2 (male) players diagnosed with concussion after direct head impacts and associated PLAs of 62g and 75g, respectively. In the setting of catching (marking) the football, female players exhibited twice the head impact rate (16 per 100 marking contests) than male players (8 per 100 marking contests). Conclusion: Playing situations in which players have limited control of the football are a common cause of impacts. Male players sustained a greater exposure to HAEs compared with female players. Female players, however, sustained higher exposure to HAEs than male players during certain skill executions, possibly reflecting differences in skill development. These findings can therefore inform match and skill development in the emerging professional women’s competition of Australian football.

The potential of head acceleration measurement to augment current best practice in concussion screening in professional Australian football players

ObjectiveTo explore the potential utility of head acceleration event (HAE) measurements to augment identification of players for further concussion screening in non-helmeted contact sport. DesignProspective observational pilot study. Participants210 (118 female) professional Australian football players in 2017 season. MethodsPlayers wore the X-Patch® accelerometer for one match each with data collected across 14 matches. Players with HAEs above thresholds associated with concussion, 95 g (males) or 85.5 g (females), were compared to players identified to have suspected concussion by club personnel during the inspected matches. Video review of matches was undertaken by a physician blinded to HAEs to identify players with concussive signs. ResultsAmong 26 players (50% female) with HAEs above threshold, two players were screened for concussion. Of the remaining 24 players, nine were not visible on video at the HAE time, six sustained verifiable head impacts, and nine sustained verifiable body impacts with no head impacts. Among 184 players with HAEs below threshold, five players were screened. ConclusionPlayers were identified to have head impacts and suspected concussion in the absence of HAEs above threshold. Use of X-Patch® was not sufficiently reliable for identifying players for further concussion screening in professional Australian football. Video review of head impacts remains essential in concussion screening.

Simplifying the complexity of assessing physical performance in professional Australian football

ABSTRACT Purpose: To provide a simplified, novel method for analysing the physical demands in an Australian Football context by reducing the dimensionality of commonly reported physical characteristics obtained from match play. This may facilitate their practical use and interpretability. Methods: A retrospective longitudinal design was utilised with individual players’ physical outputs, measured via global navigation satellite system devices, collected during official Australian Football League matches over three seasons. A principal component analysis was used to reduce a large number of correlated physical characteristics related to the analysis of physical match demands into a smaller set of uncorrelated components. Results: Forty-six variables were reduced to five principal components whilst maintaining 56% of the variance in the original dataset. The principal component analysis derived five individual-based principal components pertaining to low-moderate movement volume, high speed running volume, accelerations, change of direction and impacts. Conclusions: Utilising factor loadings (eigenvectors) derived from a principal component analysis, this study is the first to provide a simplified, novel method for analysing the physical demands in an Australian Football context with the derived metrics revealing useful information for coaches and practitioners. This may consequently guide training implementation, player performance ratings and player selection. Further, these new values may facilitate the monitoring of physical player loads.

Does a recent hamstring muscle injury affect the timing of muscle activation during high speed overground running in professional Australian Football players?

ObjectivesTo investigate if the temporal characteristics of hamstring and gluteal muscle activation are altered during high speed overground running in professional Australian Football players following hamstring muscle injury. DesignCohort study. SettingField-based testing. ParticipantsElite professional Australian Football players who had sustained a hamstring muscle injury in the six months prior to testing (n = 7) and a group of players from the same club who had no history of hamstring muscle injury (n = 8). Main outcome measuresMuscle onset timing, muscle offset timing and muscle onset duration of the medial hamstrings, biceps femoris and gluteus maximus muscles during high-speed running using electromyographic data. ResultsNo significant differences in any of the temporal aspects of muscle activation were found between groups for any of the muscles tested (p > 0.05). ConclusionsPersistent alterations to the timing of muscle activation following hamstring muscle injury that have been reported in recreational athletes were not observed during high speed running in professional athletes who have completed comprehensive rehabilitation programs.

The Effects of Endurance-Based Skills-Specific Running Loads on Same-Day Resistance-Training Performance in Professional Australian Rules Football Players.

To examine the effect of prior skills/endurance training and different recovery time periods on subsequent same-day RT performance in professional Australian football players. Sport-specific endurance-running loads (duration [in minutes], total distance [in meters], mean speed [in meters per minute], high-speed running >15km·h-1, and relative high-speed running [>75% and >85% of maximal velocity]) were obtained for 46 professional Australian football players for each training session across an entire competitive season. RT was prescribed in 3 weekly mesocycles with tonnage (in kilograms) lifted recorded as RT performance. Endurance and RT sessions were interspersed by different recovery durations: ∼20min and 1, 2, and 3h. Fixed- and mixed-effect linear models assessed the influence of skills/endurance-running loads on RT performance. Models also accounted for season period (preseason vs in-season) and recovery duration between concurrent training bouts. An increase in high-speed running and distance covered >75% and >85% of maximal velocity had the greatest reductions on RT performance. In-season total distance covered displayed greater negative effects on subsequent RT performance compared with preseason, while ∼20-min recovery between skills/endurance and RT was associated with greater reductions in RT performance, compared with 1-, 2-, and 3-h recovery. Sport-specific endurance-running loads negatively affect subsequent same-day RT performance, and this effect is greater in-season and with shorter recovery durations between bouts.