The most commonly participated team ball sport in Australia among juniors aged 15 years and older is soccer (football), with recent registration statistics suggesting that participation rates are in excess of 300,000 children (2). Second to this, Australian Rules football (ARF) currently has more than 200,000 registered participants aged 15 years and older (2). Such vast participation has driven both football codes to implement developmental programs with the intention of nurturing prospective talent. For example, Football Federation Australia recently remodeled their talent development pathway, with talent-identified (TID) junior soccer players now being invited to participate in state and national institutes before participation in elite junior squads associated with A-League (premier soccer competition in Australia) clubs. Similarly, the Australian Football League (AFL), in conjunction with state-based leagues, has established elite talent development programs referred to as State Academies, in which TID junior ARF players are invited to participate. The premise of these developmental programs is to accelerate the acquisition of expertise through the provision of specialized coaching, player welfare, and scientific and medical intervention (1,16,17). Such programs are typically administered across a preseason and modified in-season period consisting of 2–4 structured training sessions per week in addition to or in place of their normal training schedule. Furthermore, juniors are given the opportunity to compete against fellow TID peers from other State Academies or institutes in a 3- to 4-month elite national youth competition, which can provide elite senior talent recruiters the opportunity to judge prospective players within a game-based context (20).
Historically, these elite junior development programs have focused on providing an environment that harbors the development of functional, technical, and tactical skills. However, despite additionally addressing physical performance outcomes specific to game play (i.e., running endurance), these programs may not highly prioritize the development of athletic movement skill. In part, this foresight may stem from the limited educational opportunity provided to developmental coaches regarding the association between athletic movement skill (i.e., the physical process) and the physical performance outcome (i.e., jump height or sprint time) (14,15). For example, Parsonage et al. (15) demonstrated that certain athletic movement skills (defined as movements that commonly underpin strength and conditioning exercises) were associated with a superior physical performance outcome in TID junior rugby union players. This led the authors to recommend that elite junior talent development programs established in team invasion sports should intentionally seek to develop specific athletic movement skills in TID juniors (15). However, recent work demonstrates that this recommendation is yet to be applied to talent development programs in elite junior ARF (21). Specifically, Woods et al. (21) noted that TID under-18 (U18) ARF players performed certain athletic movements at a considerably lower competency than their senior AFL counterparts. This suggests that TID junior ARF players may not be adequately equipped with the necessary athletic movement skills needed to facilitate a smooth transition into elite senior competitions.
The aforementioned points may extend to junior soccer contexts given that the physical match activity profiles of players from both football codes are relatively similar. Specifically, Wehbe et al. (19) reported that elite Australian soccer players (senior A-League representatives) covered a total distance in excess of 10,000 m at a relative speed of approximately 110 m·min−1 during a 90-minute game; physical notational statistics that are consistent with elite competitions abroad (15). Additionally, players spent more than 7 percent of their total distance covered in game play at speeds greater than 19.7 km·h−1 (19). Comparatively, Veale and Pearce (18) and Burgess et al. (3) noted that elite junior and senior ARF players often cover total distances in excess of 11,500 m at 100–140 m·min−1 during a 2-hour game, while spending more than 6 percent of their total distance at speeds greater than 20 km·h−1. To maximize these physical capabilities, it is critical for physical performance specialists to prescribe appropriate physical training interventions. Typically, these interventions require well-developed athletic movement competencies inclusive of trunk or hip stability, squat and lunge capability, and a well-developed posterior chain (11). Thus, if TID juniors do not possess such competencies they may not benefit from certain training interventions, limiting their immediate performance capability on entering elite senior ranks.
In both general and athletic contexts, movement skill has historically been quantified using the Functional Movement Screen (FMS) (7,8). The FMS is purported to highlight possible asymmetries and muscular dysfunction when performing standardized foundational movements (7,8). Yet, its utility may be limited in an athletic population because it may not adequately quantify the specific athletic movement skills that are required to train, and thus compete, in team invasion sports. Recently, McKeown et al. (13) proposed the use of a reliable alternative: the Athletic Ability Assessment (AAA), which is designed to assess the athletic movement skills that commonly underpin strength and conditioning movements prescribed in elite sporting environments. Thus, the AAA may provide an informative means with which to quantify athletic movement skill in an athletic population (13).
This study aimed to compare the athletic movement skills of TID junior ARF and soccer players using a modified version of the AAA described by McKeown et al. (13). Given the suggested low priority in both elite talent development programs coupled with the similar physical requirements of competition, it was hypothesized that the athletic movement skills would not meaningfully differ between junior football codes.
Experimental Approach to the Problem
A quantitative cross-sectional observational research design was used to address the study hypothesis. Talent-identified juniors originating from elite talent development programs in their respective football codes (ARF or soccer) were required to perform a specific athletic movement skill assessment, which was modified from the AAA described by McKeown et al. (13). Subjects were unfamiliar with this assessment and were provided with specific verbal cues where necessary. After completion of this assessment, the athletic movement skill of the subjects was analyzed using a 3-point scoring criteria, with the reliability of the scores being assessed to ensure their accuracy.
Talent-identified junior soccer players (n = 17; age range = 17.9–18.7 years) and TID junior ARF players (n = 17; age range = 17.5–18.3 years) were recruited to participate in this study. To be eligible for inclusion, subjects were required to be injury-free at the time of data collection, ensuring that their athletic movement skill was not influenced by external factors (e.g., muscular contusions). Player cohorts were defined by identification in an elite talent development program within their respective football codes. Institutional ethical approval was granted by the relevant Human Ethics Advisory Committee, with all subjects (and parents or guardians if under 18 years) providing written informed consents before participation.
Each subject performed the AAA protocol, which included an overhead squat, double lunge, single-leg Romanian deadlift (both the double lunge and single-leg Romanian deadlift movements were performed on left and right legs), push-up, and chin-up. Operational definitions and assessment criteria for each movement are displayed in Table 1. All subjects were unfamiliar with the assessment protocol and were provided with standardized verbal cues and expert demonstration to guide the performance of each movement. In addition, each subject was provided with a verbal description of the scoring criteria. The overhead squat, double lunge, and Romanian deadlift were all performed with a wooden dowel to assist each subject to anatomically position themselves to perform these movements. Before undertaking the assessment, each subject performed a standardized warm-up, which consisted of light jogging and dynamic stretching. Subjects were assessed by the study's principal investigator who possessed more than 4 years' experience assessing movement skill. No augmented feedback was provided to the participants during the testing procedures to limit a potential scoring bias (9).
The scoring of each movement was completed using the criteria described in Table 1, where a specific scoring criterion was anchored to a numeric value. Each movement was performed for a total of 5 repetitions with the exception of the push-up and chin-up, which had specific repetition targets embedded within the scoring criteria. The total score for each movement (maximum of 9) and the total score for the movement assessment (each movement score summated; maximum of 63) were the criterion variables used for analysis. The scoring of each movement was performed retrospectively through the use of video footage; thus, a standard 2-dimensional camera (Sony, HDR-XR260VE, Tokyo, Japan) was placed in the optimal positions for assessment (sagittal and frontal).
The intertester reliability for each scoring item was determined to obtain psychometric results specific to the sample population described within this investigation. The score given across the 3 essential assessment regions by the study's principal investigator for each movement within the ARF sample was compared with those given by another study author who also had experience assessing movement skill. Given the categorical nature of the data, the level of agreement between the 2 scorers was measured using the weighted kappa statistic (κ). The level of agreement was defined as follows: <0, less than chance agreement; 0.01–0.20, slight agreement; 0.21–0.40, fair agreement; 0.41–0.60, moderate agreement; 0.61–0.80, substantial agreement; and 0.81–0.99, almost perfect agreement (12). The strength of the agreement for each anatomical assessment region was then averaged to provide an average level of agreement for each movement.
Descriptive statistics (mean and SDs) were calculated for the total score obtained in the AAA (maximum of 63) and the total score obtained for each individual movement (maximum of 9) for the TID juniors from both football codes. Multivariate analysis of variance (MANOVA) was used to test the main effect of football code (2 levels: ARF, soccer) on the score obtained for each movement and the total score obtained for the AAA. If required, follow-up univariate analysis of variance (1-way analysis of variance) was used to identify where statistical significance had occurred. The effect size of football code on each criterion value was calculated using Cohen's d statistic, where an effect size of d = 0.01–0.20 was considered small, d = 0.21–0.50 moderate, d = 0.51–0.80 large, and d ≥ 0.80 very large (6). For all-pairwise comparisons, the type I error was set at α < 0.05, with all analyses being performed using the SPSS statistical software (Version 22; SPSS Inc., Armonk, NY, USA, 2010).
The level of agreement between the 2 scorers is displayed in Table 2. As demonstrated, each movement reflected “ reflecteddisplayed in being n both scorers with the exception of the single-leg Romanian deadlift performed on the left leg, where “moderate agreement” was noted.
According to the Pillai's trace (V), the MANOVA revealed a significant effect of football code (V = 0.72, F = 8.18, and p < 0.01), with follow-up univariate analysis revealing a significant effect for the overhead squat and push-up movements (Table 3) (p ≤ 0.05). Specifically, the ARF subjects significantly outscored their soccer counterparts with average scores of 7.0 ± 1.5 compared with 5.0 ± 0.9 and 7.6 ± 0.9 compared with 6.7 ± 0.6 for the overhead squat and push-up, respectively. In addition, these movements also expressed very large effect sizes (Table 3). Given these 2 differences, the total score obtained by both samples also reflected a very large effect size, with the ARF subjects recording a greater total score for the movement assessment in comparison with their soccer counterparts; 41.6 ± 5.1 compared with 37.0 ± 2.9.
This study aimed to compare the athletic movement among TID juniors from different football codes, namely, ARF and soccer. Given the limited attention directed toward the development of athletic movement skill within elite junior talent development programs in both football codes, it was hypothesized that the athletic movement skill of juniors would not differ. Although partially agreeing with the hypothesis, the results did highlight points of difference for 2 of the 7 movements. Specifically, the junior ARF subjects outscored their soccer counterparts by more than 1 point (out of a total of 9) for both the overhead squat and push-up movements. This was subsequently reflected in the total score obtained by both samples, with the ARF players outscoring their soccer counterparts by an average of more than 4 points (out of a total of 63). This suggests that although TID juniors from these football codes possess similar athletic movement competencies, the requirements of ARF may facilitate the development of more advanced athletic movement when compared with soccer. Additionally, it is possible that the training practices within the ARF program directed a greater appreciation toward the acquisition of athletic movements in comparison with the soccer program. Nonetheless, given the considerable discrepancy Woods et al. (21) noted between elite junior and senior ARF players with regard to their athletic movement competency (average total score of 41.7 compared with 55.7 out of a total of 63), developmental coaches need to consider interventions designed to improve the athletic movement skill of TID juniors. Thus, athletic screening may provide an important opportunity for developmental coaches to correct inefficient movement patterns in juniors before their transition into elite senior ranks (21).
Given the similar nomadic and dynamic requirements of both football codes (3,18,19), players are likely to apply a high amount of force through the triple extension and flexion of the hip, knee, and ankle joints during game play. Such a movement pattern is reflected in the overhead squat, a movement that additionally requires the development of mobility in the thoracic region and lower extremities (4). Despite this, it was interesting to note the considerably lower movement skill shown by the TID soccer subjects when compared with their ARF counterparts. In an attempt to explain this finding, it was noted that one of the primary movement patterns performed in the warm-up protocol before training and competition by the TID junior ARF players was an overhead squat. Conversely, although a squatting movement was included in the warm-up protocol for the TID junior soccer players, they were instructed to position their hands on their hips. Hence, it is possible that the increased thoracic mobility required to perform the overhead squat was the predominant limiting factor for the TID junior soccer players. Additionally, the functional requirements of ARF dictate that players are eligible to use their arms to mark (i.e., catch) the ball and be involved in the tackling process. Comparatively, the functional requirements of soccer do not permit players to use their arms to touch the ball or tackle an opponent. Although speculative, it is possible that these functional differences translated to an increased thoracic mobility, and thus better overhead squat performance demonstrated by the ARF subjects.
It was noted that the push-up movement also reflected a difference between the football codes. This occurrence may be attributed to the slight differences in physical requirements seen in both codes. For instance, ARF permits players to bump, tackle, and wrestle in an attempt to retain or obtain possession of the ball. Primarily, ARF players perform these contacts with their upper extremities, using their arms to “fend off” or tackle opposition players. Thus, it is advantageous for ARF players at all developmental levels to possess a certain amount of upper-body strength and localized muscular endurance (10). Conversely, the requirements of soccer do not allow players to use their upper body when tackling opposition players, rather having to maneuver their lower body to deflect the ball from an opposition's possession. Consequently, the type of player chosen by talent recruiters within both football codes may reflect these requirements, and as such, junior ARF players by nature may possess greater upper-body pushing qualities in comparison with their junior soccer counterparts. However, it is important to note that the push-up criteria used here did also require players to possess total body control. Thus, in addition to possessing a superior upper-body pushing skill, it is possible that the junior ARF players were also able to maintain a stable body alignment when performing the push-up movement, contributing to their superior score.
Despite the previously discussed movements, it was expected that the athletic movement skill of TID junior ARF and soccer players would not differ, given the similar philosophies of the elite talent development programs seen in both football codes. Both programs typically focus on the development of functional, technical, and tactical skills needed to perform in elite senior contexts. However, this foresight may hinder the performance of juniors in both football codes when progressing into elite senior ranks (15). For example, the speed at which ARF is played is considerably higher in the AFL when compared with elite U18 ARF competitions (3). Notably, AFL players move at higher maximum velocities more frequently and sustain these efforts for prolonged periods when compared with players in elite U18 competitions (3). To account for this, physical development specialists will prescribe training exercises designed to optimize a player's physical match activity profile (13). However, such prescriptions may be ineffective, or even inappropriate, if a player has not developed the desired foundational athletic movement skills inclusive of squatting, lunging, pressing, and pulling variations (10). Given this, it is critical for both elite junior programs to seek methods in which players can be provided with the appropriate coaching to facilitate the development of foundational athletic movement skills (21). In turn, this may improve their physical performance (15) and possibly reduce the likelihood of injury (5).
In conclusion, our results indicate that although similarities exist between juniors in different football codes with regard to athletic movement skill, there are distinctive differences that may be explained by the unique requirements of both codes or the different training practices implemented by the coaching staff. Despite these promising findings, there are study limitations that should be addressed. Namely, although still within acceptable limits as defined by Landis and Koch (12), the moderate agreement demonstrated between the 2 scores for the single-leg Romanian deadlift suggests that continued work is required to improve the granularity of certain elements of the scoring criteria used here.
There are 3 practical applications to stem from the results of this work. First, developmental coaches in both junior ARF and soccer contexts should direct training focus toward the process (i.e., athletic movement skill) and the product (i.e., the movement outcome) when prescribing physical training to TID juniors. This may assist with the acquisition of athletic movement skill, providing the basis for the implementation of more advanced training techniques in elite senior environments. Second, the athletic movement assessment described in this study may provide coaching staff and talent recruiters with a median with which to screen the athletic qualities of juniors. This may enable the rectification of inefficient motor patterns in TID juniors before their entrance into an elite senior environment, assisting with the progression from an elite junior to an elite senior level. Third, in acknowledgment of the time constraints often associated with training sessions implemented in elite junior developmental programs, developmental coaches could include the movements described in this study in a warm-up protocol before training; thus, providing a stimulus for the acquisition of athletic movement and dynamically readying juniors for the proceeding training.
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