Physical testing characteristics better explain draft outcome than in-game movement profile in junior elite Australian rules football players

Predicting successful draft outcome in Australian Rules football: Model sensitivity is superior in neural networks when compared to logistic regression

Using logistic regression and neural networks, the aim of this study was to compare model performance when predicting player draft outcome during the 2021 AFL National Draft. Physical testing, in-game movement and technical involvements were collected from 708 elite-junior Australian Rules football players during consecutive seasons. Predictive models were generated using data from 465 players (2017 to 2020). Data from 243 players were then used to prospectively predict the 2021 AFL National Draft. Logistic regression and neural network models were compared for specificity, sensitivity and accuracy using relative cut-off thresholds from 5% to 50%. Using factored and unfactored data, and a range of relative cut-off thresholds, neural networks accounted for 73% of the 40 best performing models across positional groups and data configurations. Neural networks correctly classified more drafted players than logistic regression in 88% of cases at draft rate (15%) and convergence threshold (35%). Using individual variables across thresholds, neural networks (specificity = 79 ± 13%, sensitivity = 61 ± 24%, accuracy = 76 ± 8%) were consistently superior to logistic regression (specificity = 73 ± 15%, sensitivity = 29 ± 14%, accuracy = 66 ± 11%). Where the goal is to identify talented players with draft potential, model sensitivity is paramount, and neural networks were superior to logistic regression.

Position-Specific Running and Technical Demands During Male Elite-Junior and Elite-Senior Australian Rules Football Match-Play

ABSTRACT

Jennings, J, Štaka, Z, Wundersitz, DW, Sullivan, CJ, Cousins, SD, Čustović, E, and Kingsley, MI. Position-specific running and technical demands during male elite-junior and elite-senior Australian rules football match-play. J Strength Cond Res 37(7): 1449-1455, 2023-The aim of this study was to compare position-specific running and technical demands of elite-junior and elite-senior Australian rules football match-play to better inform practice and assist transition between the levels. Global positioning system and technical involvement data were collated from 12 Victorian U18 male NAB League ( n = 553) and 18 Australian Football League ( n = 702) teams competing in their respective 2019 seasons. Players were grouped by position as nomadic, fixed, or ruck, and data subsets were used for specific analyses. Relative total distance ( p = 0.635, trivial effect), high-speed running (HSR) distance ( p = 0.433, trivial effect), acceleration efforts ( p = 0.830, trivial effect), deceleration efforts ( p = 0.983, trivial effect), and efforts at >150 m·min -1 ( p = 0.229, trivial effect) and >200 m·min -1 ( p = 0.962, trivial effect) did not differ between elite-junior and elite-senior match-play. Elite juniors covered less total and HSR distance during peak periods (5 seconds-10 minutes) of demand ( p ≤ 0.022, small-moderate effects). Within both leagues, nomadic players had the greatest running demands followed by fixed position and then rucks. Relative disposals ( p = 0.330, trivial effect) and possessions ( p = 0.084, trivial effect) were comparable between the leagues. During peak periods (10 seconds to 2 minutes), elite juniors had less technical involvements than elite seniors ( p ≤ 0.001, small effects). Although relative running demands and positional differences were comparable between the leagues, elite juniors perform less running, HSR, and technical involvements during peak periods when compared with elite seniors. Therefore, coaching staff in elite-senior clubs should maintain intensity while progressively increasing the volume of training that recently drafted players undertake when they have transitioned from elite-junior leagues.

Including a Technical Factor with Physical and In-Game Movement Factors Improves Model Sensitivity When Evaluating Draft Outcome in Elite-Junior Australian Rules Football

Determining characteristics that define talent is critical for recruitment and player development. When developing predictive models, sensitivity is important, as it describes the ability of models to identify players with draft potential (true positives). In the current literature, modelling is limited to a small number of selected variables, and model sensitivity is often poor or unreported. The aim of this study was to determine how a technical factor combined with physical and in-game movement factors affects position-specific model sensitivity when evaluating draft outcome in an elite-junior National Australia Bank (NAB) League population. Physical, in-game movement, and technical involvement data were collated from draft-eligible (18th year) participants in the under 18 boys NAB League competition (n = 465). Factors identified through parallel analysis were used in binomial regression analyses. Models using factor combinations were developed to predict draft success for all-position, nomadic, fixed-position, and fixed&ruck players. Models that best characterised draft success were all-position (physical and technical: specificity = 97.2%, sensitivity = 36.6%, and accuracy = 86.3%), nomadic (physical and technical: specificity = 95.5%, sensitivity = 40.7%, and accuracy = 85.5%), fixed (physical: specificity = 96.4%, sensitivity = 41.7%, and accuracy = 86.6%), and fixed&ruck (physical and in-game movement: specificity = 96.3%, sensitivity = 41.2%, and accuracy = 86.7%). Including a technical factor improved sensitivity in the all-position and nomadic models. Physical factors and physical and in-game movement yielded the best models for fixed-position and fixed&ruck players, respectively. Models with improved sensitivity should be sought to assist practitioners to more confidently identify the players with draft potential.

Gender- and Sport-specific Normative Anthropometric and Physical Values in Talent-Identified High School Athletes

ABSTRACT

Larkin, P, Sortino, B, Carlon, T, Saunders, T, and Pane, C. Gender- and sport-specific normative anthropometric and physical values in talent-identified high school athletes. J Strength Cond Res 37(3): 606-615, 2023-Youth sport is associated with the identification and promotion of athletes within talent development pathways, with anthropometric and physical performance measures being key assessment and monitoring tools. To adequately evaluate performance within a population, normative reference data are needed; however, currently, there is limited normative values of talent-identified youth athletes. The aim of the current study is to present normative values of talent-identified youth sport academy athletes in relation to gender, age, and sport. Over a 5-year period, a total of 794 talent-identified youth athletes who attended a specialized school sports academy were assessed using anthropometric (i.e., heigh,; body mass) and physical performance (i.e., vertical jump, 20-m sprint, Yo-Yo intermittent recovery test 1) measures. In total, 451 male and 343 female athletes (grade 7: 12-13 years; grade 8: 13-14 years; grade 9: 14-15 years; grade 10: 15-16 years) were tested annually. The result demonstrates that for each gender, as age increases, there is a general increase in anthropometric measures (i.e., height and body mass). Furthermore, with increasing age, athletes generally have a higher vertical jump, faster sprint performance, and improved physical endurance. The results highlight sport-specific differences for each measure. Overall, the results of the study provides age-, gender-, and sport-specific normative data of talent-identified youth athletes. These findings provide representative performance profiles of talent-identified high school athletes, with the values potentially being used by coaching staff (i.e., head coaches, strength and conditioning coaches, rehabilitation staff) for comparison purposes.

Anthropometry and Physical Performance in 13-Year-Old Australian Talent-Identified Male and Female Athletes Compared to an Age-Matched General Population Cohort

Talent-identified male and female athletes are assumed to have greater speed and power than the general population at a given age. However, a comparison of the jump and sprint performance of an Australian cohort of male and female youth athletes from various sports to age-matched controls has not occurred. Therefore, the aim of this study was to compare anthropometric and physical performance markers between ~13-year-old talent-identified youth athletes and general population Australian youth. The anthropometry and physical performance in talent-identified youth athletes (n = 136, 83 males) and general population youth (n = 250, 135 males) were tested during the first month of the school year in an Australian high school within a specialized sports academy. Talent-identified females were taller (p < 0.001; d = 0.60), sprinted faster (20 m: p < 0.001; d = -1.16), and jumped higher (p < 0.001; d = 0.88) than general population youth females. Similarly, talent-identified males sprinted faster (20 m: p < 0.001; d = -0.78) and jumped higher (p < 0.001; d = 0.87) than general population youth males, but were not taller (p = 0.13; d = 0.21). Body mass was not different between groups for males (p = 0.310) or females (p = 0.723). Overall, youth, particularly females, who are trained in a variety of sports, exhibit greater speed and power during early adolescence compared to their age-matched peers, with anthropometric differences only occurring in females at 13 years of age. Whether talented athletes are selected because they exhibit these traits or whether speed and power are developed through sport participation requires further investigation.

Methodological Approaches to Talent Identification in Team Sports: A Narrative Review

Talent identification (TID) and talent development (TD) continue to receive significant investment from team sports organisations, highlighting their importance in attempting to identify potential elite athletes. Accompanying this continual pursuit to unearth future talent is an ever-increasing body of research aiming to provide solutions and strategies to optimise TID and TD processes. Therefore, the aim of this review is to provide a summary and critical synthesis of the methodological approaches applied to TID in team sports and present considerations for future TID research. Specifically, this review highlights three key areas for consideration: (1) the timespan of the research design; (2) the use of monodisciplinary or multidisciplinary variables; and (3) the fidelity of the methodological approaches to the assessment of talent. The review highlights the benefits of longitudinal, multidisciplinary, and ecologically valid research designs for TID within team sports.