Professional Australian Football Research Articles

The Eye in the Sky—A Method to Obtain On-Field Locations of Australian Rules Football Athletes

The ability to overcome an opposition in team sports is reliant upon an understanding of the tactical behaviour of the opposing team members. Recent research is limited to a performance analysts’ own playing team members, as the required opposing team athletes’ geolocation (GPS) data are unavailable. However, in professional Australian rules Football (AF), animations of athlete GPS data from all teams are commercially available. The purpose of this technical study was to obtain the on-field location of AF athletes from animations of the 2019 Australian Football League season to enable the examination of the tactical behaviour of any team. The pre-trained object detection model YOLOv4 was fine-tuned to detect players, and a custom convolutional neural network was trained to track numbers in the animations. The object detection and the athlete tracking achieved an accuracy of 0.94 and 0.98, respectively. Subsequent scaling and translation coefficients were determined through solving an optimisation problem to transform the pixel coordinate positions of a tracked player number to field-relative Cartesian coordinates. The derived equations achieved an average Euclidean distance from the athletes’ raw GPS data of 2.63 m. The proposed athlete detection and tracking approach is a novel methodology to obtain the on-field positions of AF athletes in the absence of direct measures, which may be used for the analysis of opposition collective team behaviour and in the development of interactive play sketching AF tools.

A CASE STUDY OF THE PHYSIOLOGICAL AND PSYCHOLOGICAL RESPONSES TO COACHING PROFESSIONAL AUSTRALIAN FOOTBALL

INTRODUCTION & AIMS Coaching professional sport is stressful, yet there is little information detailing the physiological and psychological responses of coaches during match-play. The burden of measurement instruments during competition may preclude their use with coaches during this high-pressure part of the coaching cycle. This exploratory case study examined physiological and psychological alterations when coaching professional Australian football to determine the potential health implications and enhance health literacy in coaches. METHODS One head coach of a professional football team was monitored for heart rate (HR), stress-related hormones (C-Reactive Protein, Cortisol, Troponin, Brain Natriuretic Peptide) and psychological stress prior to, during and following seven matches and descriptive data was examined. RESULTS The HR response indicated sustained elevation during match-play, with the intermittent nature of the game causing an undulating profile. Periods of locomotion during breaks in play led to elevations in HR, with maximum HR recorded as 8% above age-predicted maximum. Further, differences in HR were evident in the final five minutes between small (145 ± 7.0 bpm) and large (113 ± 5.1 bpm) score margins. There were no irregularities for stress hormones, while the psychological questionnaire revealed differences in perceptions of accomplishment, success, recovery and stress related to match outcome. CONCLUSIONS This exploratory case study indicated that substantial elevations in HR are evident while coaching professional football, yielding implications for health management. Coaches require appropriate levels of cardiovascular health to cope with the demands of coaching and targeted health intervention programs may be warranted. Further, differences in psychological outcomes from winning or losing may reflect the need to develop recovery and coping strategies that are contextualised to match results. Since match-play observation elicits alterations to physical and psychological markers, confirmatory research with larger cohorts is warranted to examine and enhance well-being and health management strategies in these elite performers.

Australian Football Coaches’ Tales of Mental Toughness: Exploring the Sociocultural Roots

The present study explored how three professional Australian football coaches learned and understood mental toughness. Participants shared stories regarding mental toughness through semistructured interviews. Reflexive thematic analysis was used to interpret the data. Creative nonfiction was employed to develop a composite story. All participants’ voices contributed equally to the narrative, which follows Sam (our composite coach) through three periods in his career: as a junior player, an elite footballer, and, finally, a coach in the professional football environment. Mental toughness was fundamentally determined by the sociocultural environment in which one was immersed. Athletes and coaches were expected to internalize dominant understandings of mental toughness and reinforce ideals and were punished if they deviated from mentally tough standards set up in their clubs. Mental toughness was defined by various values, beliefs, and norms that originated from the sociocultural environment, indicating the importance of context in understanding the roots of being mentally tough.

An observational study of player behaviours under varying task constraints in professional Australian football players

An evaluation of player behaviour and performance across different playing conditions in team sport is difficult. This study examined integrative (indegree and outdegree importance) and individual (goals, kicks, handballs, marks, tackles, kick and handball proficiency) level behaviours at one professional Australian Football club across three different conditions: small-sided games (SSGs), match simulation and competitive Australian Football League (AFL) matches. Estimated marginal means identified negligible changes for integrative measures across conditions. This may suggest larger changes to control parameters are required to modify these behaviours, as it relies on interdependent cooperative behaviour. Individual level behaviours demonstrated varied responses across changing conditions. AFL matches revealed the lowest kicks and marks per minute compared to the other conditions, whilst having the highest rate of tackles. Players had lower kick proficiency in conditions with a higher number of players. Moreover, one SSG with a floater (player who participates in attack for both teams) elicited a higher number of handballs per minute relative to every other condition. These findings provide implications for measuring the (in)stability of individual and integrative level behaviours and how changes to constraints may alter these metrics. This method may provide a foundation for future hypotheses testing and for player monitoring that can assist practitioners to examine the changes in players behaviours in response to changing constraints.

Does game-based training replicate match inside-50 entries in elite Australian Rules football?

The purpose of this research was to determine if the training design of an elite Australian Rules football team replicated match conditions for inside-50 entries. Notational analyses of one professional Australian Rules football club's training and match footage were conducted for every disposal that entered the inside-50 during either game-based training or matches. Analysed variables included how the ball was received, time in possession and location. Statistical analyses were undertaken using Mann–Whitney tests, a multivariate analysis of variance and a decision tree analysis. Significant differences were identified between game-based training and competition matches for 34 of the 54 inside-50 entry variables. Of these 34 variables, 10 showed a strong effect between session types. When examining the efficiency of inside-50 entries, only effective disposals produced a significant difference between training and matches, with no differences for neutral and ineffective disposals. The session type, how the ball was received, decision (e.g., kick vs. handball) and pressure acts were the most important contributors to effective inside-50 entry disposal efficiency. The results suggest this professional Australian Rules team does not participate in training sessions that reflect inside-50 match conditions. This study may provide a framework for elite Australian Rules teams on which to structure their inside-50 training.

Associations between hamstring strain and knee ligament injuries with isometric trunk and hip strength and morphology in professional Australian rules football and rugby league players

Associations between hamstring strain and knee ligament injuries with isometric trunk and hip strength and morphology in professional Australian rules football and rugby league players

Hamstring Strain Injury Risk Factors in Australian Football Change over the Course of the Season.

This study aimed to determine which factors were most predictive of hamstring strain injury (HSI) during different stages of the competition in professional Australian Football. Across two competitive seasons, eccentric knee flexor strength and biceps femoris long head architecture of 311 Australian Football players (455 player seasons) were assessed at the start and end of preseason and in the middle of the competitive season. Details of any prospective HSI were collated by medical staff of participating teams. Multiple logistic regression models were built to identify important risk factors for HSI at the different time points across the season. There were 16, 33, and 21 new HSIs reported in preseason, early in-season, and late in-season, respectively, across two competitive seasons. Multivariate logistic regression and recursive feature selection revealed that risk factors were different for preseason, early in-season, and late in-season HSIs. A combination of previous HSI, age, height, and muscle thickness were most associated with preseason injuries (median area under the curve [AUC], 0.83). Pennation angle and fascicle length had the strongest association with early in-season injuries (median AUC, 0.86). None of the input variables were associated with late in-season injuries (median AUC, 0.46). The identification of early in-season HSI and late in-season HSI was not improved by the magnitude of change of data across preseason (median AUC, 0.67). Risk factors associated with prospective HSI were different across the season in Australian Rules Football, with nonmodifiable factors (previous HSI, age, and height) mostly associated with preseason injuries. Early in-season HSI were associated with modifiable factors, notably biceps femoris long head architectural measures. The prediction of in-season HSI was not improved by assessing the magnitude of change in data across preseason.

‘A Different Ball Game’: Adaptation of a men’s health program for implementation in rural Australia

BackgroundMen residing in rural areas are less likely to participate in weight management interventions than women, and few men-specific programs target rural areas. Aussie-Fans in Training (Aussie-FIT) is an evidence-based weight management intervention that uses professional Australian Football club affiliations and settings as a ‘hook’ to engage urban-residing men. The aim of this study is to report on how findings from rural stakeholder focus groups were used to inform the adaptation of Aussie-FIT for implementation in rural areas.MethodsSeven focus groups with stakeholders (n = 24) in three rural towns explored existing weight management and physical activity provisions, barriers and facilitators to engaging men, and considerations for adapting Aussie-FIT for implementation in rural contexts. Qualitative data were analysed using the framework approach. Adaptations made to the Aussie-FIT program and strategies to implement the program in rural contexts were reported using a structured framework.ResultsThemes generated from our analysis include limited appealing services for men, Australian Football as a ‘common language’, the influence of the ‘smaller fishpond’(population), considerations for program inclusivity, and the importance of local partner organisations for sustainability. We adapted the recruitment and marketing strategies, delivery settings, football program theme and partnerships for rural implementation. Stakeholders advised that an Australian Football program theme without specific local club affiliations would be important to avoid alienating men with differing club allegiances or non-sporting backgrounds. A multi-component recruitment strategy utilising local trusted sources, and program marketing that aligns with masculine ideals were considered important by stakeholders in small communities where ‘people talk’.ConclusionsRural areas were described as ‘a different ball game’ due to limited local services and resources in comparison to metropolitan areas. Study findings have synergies with previous studies undertaken in rural contexts including in relation to the power of word of mouth, the importance of trust, and local partner organisations. Findings have implications for engaging rural men in health interventions in rural contexts where professional sporting contexts are not available. Assessing the extent to which the adapted Aussie-FIT program can reach and engage men in rural Australia, and exploring the barriers and facilitators to delivering the program in rural contexts is required.

Discovery and Characterisation of Forward Line Formations at Centre Bounces in the Australian Football League.

The extent of player formation usage and the characteristics of player arrangements are not well understood in Australian football, unlike other team-based invasion sports. Using player location data from all centre bounces in the 2021 Australian Football League season; this study described the spatial characteristics and roles of players in the forward line. Summary metrics indicated that teams differed in how spread out their forward players were (deviation away from the goal-to-goal axis and convex hull area) but were similar with regard to the centroid of player locations. Cluster analysis, along with visual inspection of player densities, clearly showed the presence of different repeated structures or formations used by teams. Teams also differed in their choice of player role combinations in forward lines at centre bounces. New terminology was proposed to describe the characteristics of forward line formations used in professional Australian Football.

Does Headgear Prevent Sport-Related Concussion? A Systematic Review and Meta-Analysis of Randomized Controlled Trials Including 6311 Players and 173,383 Exposure Hours.

A sport-related concussion (SRC) is a traumatic brain injury that is caused by biomechanical stresses and results in a complex pathophysiological process in the brain. Some in the sporting community believe that headgear (HG) can prevent SRC, and several professional Australian sports organizations, including rugby, football, and soccer clubs, recommend its use. The purpose of this study is to determine whether HG is effective in lowering the prevalence of SRC in sports. A systematic search for related studies published between 1985 and 2023 was conducted using the following databases: Cochrane Library, AMED, PubMed, Web of Science, and Physiotherapy Evidence Database (PEDro). Only randomized controlled trials (RCTs) that investigated the effectiveness of HG in reducing SRC rate were included. Systematic review and meta-analysis of RCTs. Level 1a. Two researchers independently completed the title and abstract search and performed full-text reviews. A third reviewer was consulted to reach a consensus if any discrepancies were noted. The PEDro scale was used to evaluate the quality of the included RCTs. Data recorded from each study included authors, year of publication, type and number of players, study design, duration of the study, injury rate, compliance (%), sports/level, and exposure hours. The pooled results of 6311 players and 173,383 exposure hours showed 0% SRC reduction per 1000 hours of exposure in the experimental group compared with the control group, with an injury risk ratio of 1.03 (95% CI, 0.82-1.30; P = 0.79). This systematic review and meta-analysis demonstrates that HG does not prevent SRC among soccer and rugby players, and therefore the findings from this meta-analysis do not currently support the use of HG to prevent SRC in soccer or rugby.

Phases of Match-Play in Professional Australian Football: Positional Demands and Match-Related Fatigue.

This study examined the influence of player position and match quarter on activity profiles during the phases of play in Australian Football. Global positioning satellite data was collected for one season from an Australian Football League team for nomadic, key position and ruck players (age: 24.8 ± 4.2 years, body mass: 88.3 ± 8.7 kg, height: 1.88 ± 0.8 m). Separate linear mixed models and effect sizes were used to analyse differences between positions and game quarter within each phase of play for values of distance, speed and metabolic power indices. There were clear differences between positions for low-speed running, high-speed running, total distance and average speed. Nomadic players generally recorded the highest match running outputs, followed by key position players and ruckmen. Within each position, offence and defence involved the highest intensities, followed by contested play and then stoppage periods. Across the four quarters, there were small to large reductions in average speed, high-speed running, high power and energy expenditure during offence, defence and contested play, but not during stoppages. Accordingly, conditioning staff should consider the intermittent intensities of the phases of match-play for each position to optimally prepare players for competition. Reductions in match intensities were evident during active periods of play providing implications for real-time monitoring to optimise the timing of rotations.

Evaluating the influence of a constraint manipulation on technical, tactical and physical athlete behaviour.

Evaluating practice design is an important component of supporting skill acquisition and improving team-sport performance. Constraint manipulations, including creating a numerical advantage or disadvantage during training, may be implemented by coaches to influence aspects of player or team behaviour. This study presents methods to evaluate the interaction between technical, tactical and physical behaviours of professional Australian Football players during numerical advantage and disadvantage conditions within a small-sided game. During each repetition of the game, team behaviour was manually annotated to determine: repetition duration, disposal speed, total disposals, efficiency, and disposal type. Global Positioning System devices were used to quantify tactical (surface area) and physical (velocity and high intensity running) variables. A rule association and classification tree analysis were undertaken. The top five rules for each constraint manipulation had confidence levels between 73.3% and 100%, which identified the most frequent behaviour interactions. Specifically, four advantage rules involved high surface area and medium high intensity running indicating the attacking team's frequent movement solution within this constraint. The classification tree included three behaviour metrics: surface area, velocity 1SD and repetition duration, and identified two unique movement solutions for each constraint manipulation. These results may inform if player behaviour is achieving the desired outcomes of a constraint manipulation, which could help practitioners determine the efficacy of a training task. Further, critical constraint values provided by the models may guide practitioners in their ongoing constraint manipulations to facilitate skill acquisition. Sport practitioners can adapt these methods to evaluate constraint manipulations and inform practice design.

The association of player wellness data and running performance in professional Australian football athletes

Introduction: Wellness questionnaires are frequently used by professional Australian football teams to monitor stress and biopsychosocial states. They have been shown to be sensitive to changes in training load and, in some sports, to influence total running volume. The purpose of this study was to compare player wellness data with external running load, with the aim of determining if there was any association between wellness questionnaires and high-speed running or acceleration density during games.

The influence of individual, task and environmental constraint interaction on skilled behaviour in Australian Football training

ABSTRACT An important consideration for sport practitioners is the design of training environments that facilitate skill learning. This study presented a method to determine individual (age, games played, height, mass, and position), environmental (activity type) and task (pressure and possession time) constraint interaction to evaluate player training behaviour. Skill actions (n = 7301) were recorded during training activities (n = 209) at a single professional Australian Football club and four measures of player behaviour were determined: disposal frequency, kick percentage, pressure, and possession time. K-means clustering assigned training activities into four groups, with regression trees used to determine the interaction between constraints and their influence on disposal frequency and type. For most regression trees, only the environmental constraint was included. This showed all players adapted similarly to the constraints of each training activity. In one exception, a critical value of 60 games experience was identified as an individual constraint which interacted with activity type one to influence disposal frequency. Practically, this individual constraint value could be used to guide training design by grouping players of similar experience together. This study is presented as a practical tool for sport practitioners, which considers constraint interaction, to evaluate player behaviour and inform training design.

Video Analysis of Pectoralis Major Injuries in Professional Australian Football Players.

Background:There is little evidence regarding the mechanisms of pectoralis major (PM) injury and player outcomes in Australian Football League (AFL) players.Purposes/Hypothesis:The study aims were to investigate (1) the mechanisms of PM muscle injury in elite AFL players via video analysis and (2) the player profile, method of management, and clinical outcomes of the PM injuries sustained. We hypothesized that the majority of PM tears would occur in outer-range PM positions (hyperextension of the glenohumeral joint).Study Design:Case series; Level of evidence, 4.Methods:We analyzed video of the precipitating event for traumatic PM injuries during AFL competition or training over a 20-year period (2002-2021). The footage was analyzed by 4 experienced assessors, and the following were evaluated: mechanism of injury, injury variables (arm position, initial contact point, visual awareness, and use of taping), player characteristics (age at the time of injury, hand dominance, and history of injury), injury profile (location and size of tear), method of management (operative vs nonoperative), patient outcomes (time to return to full senior training/match play), and complication rates.Results:The mean ± standard deviation age of the players was 26.5 ± 3.1 years (range, 21-32 years). Overall, 22 PM injuries were identified in the AFL injury database for a rate of 1.1 per year; 16 of these injuries had accompanying video footage. We identified 3 mechanisms for PM injury: horizontal hyperextension (62.5%), hyperflexion-abduction (25.0%), and horizontal adduction (sustained tackling; 12.5%). The most common site of the tear was the insertion point of the sternocostal head (91.0%). Twenty players (91.0%) required surgical repair, with 75% undergoing surgery within 1 week (range, 0-26 weeks). The mean return to competition for the surgical repair group was 11.1 weeks (range, 8-15 weeks). The rerupture rate was 5.0% (1 repair; <4 weeks postoperatively in 2004).Conclusion:PM tears in elite male AFL players were due to 1 of 3 distinct mechanisms: horizontal hyperextension, hyperflexion-abduction, and horizontal adduction (sustained tackling). Players returned to play on average 11 weeks after injury. Knowledge regarding mechanisms of injury, player profile, and return-to-sport timelines is important for appropriate medical management and provides potential areas to target for prevention of PM injuries.

Effects of concussion on technical performance in professional Australian football

ABSTRACT Introduction There is limited research on the on-field performance of previously concussed athletes. The aim of this exploratory study was to investigate athlete technical performance pre- and post-concussion in Australian Football. Methods Using publicly available data, male athletes who sustained a concussion during the 2016–19 professional Australian Football League seasons were analysed across five games pre- and post-concussion (concussion events n = 41, age 25.4 ± 3.5 years; control n = 39, age 25.2 ± 3.6 years). Mean technical performance metrics (goals, time-on-ground percentage, kicks, ground ball and disposal efficiency, contested marks) over the five games pre- and post-concussion, as well as within-athlete performance variability measures (standard deviation and coefficient of variation) were analysed. Results Results showed no significant group-by-time interactions, nor effect of time (pre-post) for any technical performance metric. Similarly, the within-athlete standard deviation and coefficient of variation of technical performance metrics showed no group-by-time interaction, nor effect for time. Conclusion This retrospective study has shown that athlete performance averaged over five games is not affected post-concussion in elite men’s Australian Football. Further prospective studies controlling for contextual match factors based on opposition and environmental conditions may be required to identify potential in-game technical performance changes following return-to-play from concussion.

White matter abnormalities characterize the acute stage of sports-related mild traumatic brain injury.

Sports-related concussion, a form of mild traumatic brain injury, is characterized by transient disturbances of brain function. There is increasing evidence that functional brain changes may be driven by subtle abnormalities in white matter microstructure, and diffusion MRI has been instrumental in demonstrating these white matter abnormalities in vivo. However, the reported location and direction of the observed white matter changes in mild traumatic brain injury are variable, likely attributable to the inherent limitations of the white matter models used. This cross-sectional study applies an advanced and robust technique known as fixel-based analysis to investigate fibre tract-specific abnormalities in professional Australian Football League players with a recent mild traumatic brain injury. We used the fixel-based analysis framework to identify common abnormalities found in specific fibre tracts in participants with an acute injury (≤12 days after injury; n = 14). We then assessed whether similar changes exist in subacute injury (>12 days and <3 months after injury; n = 15). The control group was 29 neurologically healthy control participants. We assessed microstructural differences in fibre density and fibre bundle morphology and performed whole-brain fixel-based analysis to compare groups. Subsequent tract-of-interest analyses were performed within five selected white matter tracts to investigate the relationship between the observed tract-specific abnormalities and days since injury and the relationship between these tract-specific changes with cognitive abnormalities. Our whole-brain analyses revealed significant increases in fibre density and bundle cross-section in the acute mild traumatic brain injury group when compared with controls. The acute mild traumatic brain injury group showed even more extensive differences when compared with the subacute injury group than with controls. The fibre structures affected in acute concussion included the corpus callosum, left prefrontal and left parahippocampal white matter. The fibre density and cross-sectional increases were independent of time since injury in the acute injury group, and were not associated with cognitive deficits. Overall, this study demonstrates that acute mild traumatic brain injury is characterized by specific white matter abnormalities, which are compatible with tract-specific cytotoxic oedema. These potential oedematous changes were absent in our subacute mild traumatic brain injury participants, suggesting that they may normalize within 12 days after injury, although subtle abnormalities may persist in the subacute stage. Future longitudinal studies are needed to elucidate individualized recovery after brain injury.

EXPLORING THE SOCIAL CONSTRUCTION OF FOOTBALL COACHING BY A PROFESSIONAL FOOTBALL COACH: TOWARD THE DEVELOPMENT OF ENGLISH PEDAGOGICAL RESOURCES FOR SPORTS

Globalization has had a significant impact on the field of sports. In Japan, an increasing number of football coaches are looking overseas for career opportunities; however, they face numerous obstacles when attempting to accomplish their goals, including language barriers, cultural adaptation, and competition-specific misalignments. This study aimed to develop language teaching materials specifically designed for football coaches interested in pursuing professional careers abroad in the future. For this purpose, this study conducted a preliminary investigation of how a Japanese football coach interacted in English with players in an academy team of an Australian professional football club. The coaching behavior was analyzed using a qualitative data analysis method called the modified grounded theory approach (M-GTA). The results revealed the coach’s training process, which began with an explanation of the purpose and procedure of the training, followed by feedback on the training and temporarily suspending the training to correct the players’ errors. The coach’s unique technique involved using repeated initiation, response, evaluation, and clarification (IRE-C) interactions with the players, primarily questioning them to elicit consideration of methods to enhance their performance, followed by gentle guidance toward a solution.The findings had several pedagogical implications. First, the repeated generic structure and linguistic features identified in the coaching process could form foundational resources for developing ESP materials. Second, rich contextual information surrounding the obtained linguistic data, such as the coach’s mindset and coaching philosophy, could reveal how language is used and help construct meaning in authentic football coaching situations.

The relationship between team-level and league-level injury rate, type and location in a professional football league

ObjectivesTo describe the relationship between team- and league-level variability of injury rate, type, and location over 6 seasons in professional Australian football (A-League). DesignProspective epidemiological study. MethodsInjury incidence, type and location were collected from all A-League teams (n = 10) for 6 consecutive seasons (2012/13 to 2017/18) via a standardised injury surveillance system. Intra-class correlation and coefficient of variation were calculated to assess the between-season variability of injury measures for each team. To determine the relationship between team-level injury variability on league-level injury rates, Marginal Coefficient of Determination to Coefficient of Determination were then calculated from generalised linear mixed models. This allowed determination between season trends, where league-level injury incidence, type- and location rates as the response variables, season as the predictor variable and teams as random intercepts. ResultsThe majority of teams showed poor to moderate correlations for between-season injury rates (intra-class correlation: r = 0.319–0.831), but also showed low–moderate variability between-seasons for injury rate (coefficient of variation 34 ± 22%). League injury rates were stable, though were reduced in 2015/16 compared to 2012/13 (β = 0.738; p = 0.011). Joint/Ligament injuries had coinciding significant reduction in 2015/16 (p = 0.001). The model variance showed the reduction of Joint/Ligament injuries was league-wide rather than team-specific (Marginal Coefficient of Determintion = 0.23; Coefficient of Determination = 0.23). ConclusionsIn the A-League, low between-season injury rate variability from teams contributed to a stable league-level injury trend over seasons. A reduction in league injury rate in 2015/16 was mirrored by league-wide Joint/Ligament injury rates, without specific effect by team.

Predicting Noncontact Lower Limb Injury Using Lumbar Morphology in Professional Australian Football and Rugby League Players.

Noncontact lower limb injuries are common within the Australian Football League (AFL) and National Rugby League (NRL). Smaller (<8.5 cm2) lumbar multifidus at the fifth vertebra (LM L5) and larger (>8.2 cm2) quadratus lumborum (QL) cross-sectional area (CSA) have been associated with increased noncontact lower limb injury risk in AFL players. These associations have not been explored in an NRL cohort. This study will attempt to replicate previous research findings by confirming that muscle morphology is associated with noncontact lower limb injury. AFL (n = 87) and NRL (n = 151) players underwent LM L2-L5 and QL CSA ultrasound measures during preseason. Each club's medical staff reported all noncontact lower limb injuries sustained in the subsequent regular season. LM and QL CSA, age, body mass index, and noncontact lower limb injuries were analyzed using multivariable logistic regression. Seventy-two players sustained a noncontact lower limb injury in the 2020 regular season (AFL = 21, NRL = 51). The multivariable logistic regression (odds ratio (OR) = 1.36; 95% confidence interval (CI), 1.02-1.85; P = 0.038) identified AFL players with larger QL CSA at increased risk of sustaining a noncontact lower limb injury during the regular season, but no relationship was found for LM CSA and noncontact lower limb injuries in the AFL (OR = 1.01; 95% CI, 0.36-2.78; P = 0.591) or NRL (OR = 0.63; 95% CI, 0.29-1.33; P = 0.149). AFL players who sustained regular season noncontact lower limb injuries had larger QL CSA in preseason tests. No significant associations between either LM L5 CSA or LM L5 to QL ratio and regular season noncontact lower limb injuries were found.