Development of a Machine-Learning-Based Classifier for the Identification of Head and Body Impacts in Elite Level Australian Rules Football Players

Background: Exposure to thousands of head and body impacts during a career in contact and collision sports may contribute to current or later life issues related to brain health. Wearable technology enables the measurement of impact exposure. The validation of impact detection is required for accurate exposure monitoring. In this study, we present a method of automatic identification (classification) of head and body impacts using an instrumented mouthguard, video-verified impacts, and machine-learning algorithms.Methods: Time series data were collected via the Nexus A9 mouthguard from 60 elite level men (mean age = 26.33; SD = 3.79) and four women (mean age = 25.50; SD = 5.91) from the Australian Rules Football players from eight clubs, participating in 119 games during the 2020 season. Ground truth data labeling on the captures used in this machine learning study was performed through the analysis of game footage by two expert video reviewers using SportCode and Catapult Vision. The visual labeling process occurred independently of the mouthguard time series data. True positive captures (captures where the reviewer directly observed contact between the mouthguard wearer and another player, the ball, or the ground) were defined as hits. Spectral and convolutional kernel based features were extracted from time series data. Performances of untuned classification algorithms from scikit-learn in addition to XGBoost were assessed to select the best performing baseline method for tuning.Results: Based on performance, XGBoost was selected as the classifier algorithm for tuning. A total of 13,712 video verified captures were collected and used to train and validate the classifier. True positive detection ranged from 94.67% in the Test set to 100% in the hold out set. True negatives ranged from 95.65 to 96.83% in the test and rest sets, respectively.Discussion and conclusion: This study suggests the potential for high performing impact classification models to be used for Australian Rules Football and highlights the importance of frequencies <150 Hz for the identification of these impacts.

Television commentary on women's and men's Australian Rules football: A thematic analysis

Commentators are reported to describe male and female players in different ways across a range of sports. The present study examines televised commentary on men's and women's games in the Australian Football League during the inaugural season of the women's professional competition. A two-phase thematic analysis was applied to television commentary on 10 men's and 10 women's Australian Rules football games. Semantic thematic analysis of the broad descriptive categories used by commentators for men's and women's matches indicated greater similarity than had been reported for televised commentary of other sports like tennis, in line with recent reports of progress towards greater gender equality in sports media reporting. Although technical descriptors were used slightly more frequently in describing men's play, there were no major differences in frequency for a number of other descriptive categories (mental, physical, personal or tactical) that have previously been observed as discriminating commentary on men's and women's sport. More in-depth, discursive thematic analysis did indicate some specific patterns of difference: terms, features and details used in commentary resulted in a greater focus on women's athletic weaknesses, and negative aspects of their skills and mentality. Identification of subtle linguistic features that minimise the athleticism and accomplishments of female players suggests that continued examination of media reporting on women's increasing involvement in traditional male sports can contribute important insights for promoting gender equality.

Traumatic Pediatric Tracheal Rupture After Blunt Force Sporting Injury: Case Report and Review of the Literature

Objective: This paper presents the case of a traumatic tracheal rupture in a pediatric patient. The body of literature of the clinical features, evaluation, and management of this uncommon presentation is discussed. Case: A 13-year-old boy sustained an intrathoracic tracheal rupture whilst playing Australian Rules football. He developed hallmark clinical features of air extravasation and was intubated prior to transfer to a tertiary pediatric center for further management. After a short trial of conservative management, his respiratory status deteriorated and he was taken to the operating theater for open surgical repair of the defect. Conclusion: Traumatic rupture of the trachea is a rare injury in children. This case demonstrates the dynamic nature of this serious injury and the need for multidisciplinary care in achieving the optimal outcome.

Revisiting youth player development in Australian Rules Football: Is there a place for bio-banding?

Within a group of adolescent Australian Rules Football (ARF) players, individuals of the same chronological age can differ greatly in biological maturation, with some players maturing vastly earlier or later than their peers. Such large differences in maturity can cause a disparity between physical performance, influence the perceptions of talent, and affect training practice. In attempts to address such issues, this overview proposes the concept of bio-banding in ARF, which may be used periodically within the national talent pathway to optimise player development. Bio-banding is the process of grouping adolescent athletes into specific categories or ‘bands’ based on biological maturation, rather than chronological age. This review describes how bio-banding may be used to enhance player development in ARF, giving context to its background and implementation in other sports.

Clinical relevance of MRI knee abnormalities in Australian rules football players: a longitudinal study

Background/AimThe clinical relevance of MRI knee abnormalities in athletes is unclear. This study aimed to determine the prevalence of MRI knee abnormalities in Australian Rules Football (ARF) players and describe their associations with pain, function, past and incident injury and surgery history.Methods75 male players (mean age 21, range 16–30) from the Tasmanian State Football League were examined early in the playing season (baseline). History of knee injury/surgery and knee pain and function were assessed. Players underwent MRI scans of both knees at baseline. Clinical measurements and MRI scans were repeated at the end of the season, and incident knee injuries during the season were recorded.ResultsMRI knee abnormalities were common at baseline (67% bone marrow lesions, 16% meniscal tear/extrusion, 43% cartilage defects, 67% effusion synovitis). Meniscal tears/extrusion and synovial fluid volume were positively associated with knee symptoms, but these associations were small in magnitude and did not persist after further accounting for injury history. Players with a history of injury were at a greater risk of having meniscal tears/extrusion, effusion synovitis and greater synovial fluid volume. In contrast, players with a history of surgery were at a greater risk of having cartilage defects and meniscal tears/extrusion. Incident injuries were significantly associated with worsening symptoms, BML development and incident meniscal damage.ConclusionsMRI abnormalities are common in ARF players, are linked to a previous knee injury and surgery history, as well as incident injury but do not dictate clinical symptomatology.

Team numerical advantage in Australian rules football: A missing piece of the scoring puzzle?

The primary aim of this study was to determine the relationship between a team numerical advantage during structured phases of play and match event outcomes in professional Australian football. The secondary aim was to quantify how players occupy different sub-areas of the playing field in match play, while accounting for match phase and ball location. Spatiotemporal player tracking data and play-by-play event data from professional players and teams were collected from the 2019 Australian Football League season played at a single stadium. Logistic regression analysed the relationship between total players and team numerical advantage during clearances and inside 50’s. Total players and team numerical advantage were also quantified continuously throughout a match, which were separated into three match phases (offence, defence, and stoppage) and four field positions (defensive 50, defensive midfield, attacking midfield, and forward 50). Results identified an increased team numerical advantage produced a greater likelihood of gaining possession from clearances or generating a score from inside 50’s. Although, an increased number of total players inside 50 was likely associated with a concomitant decrease in the probability of scoring, irrespective of a team numerical advantage. Teams were largely outnumbered when the ball was in their forward 50 but attained a numerical advantage when the ball was in the defensive 50.