Australian Rules football: an anthropometric study of participants

Combine performance, draft position and playing position are poor predictors of player career outcomes in the Australian Football League

Physical testing-based draft combines are undertaken across various sporting codes to inform talent selection. To determine the explanatory power of the Australian football league (AFL) draft combine, participants drafted between 1999-2016 (n = 1488) were assessed. Testing performance, draft selection order and playing position, AFL matches played, AFL player ranking points and AFL player rating points were collected as career outcomes. Boosted regression tree analysis revealed that position and draft selection order were the most explanatory variables of career outcomes. Linear modelling based on testing results is able to explain 4% of matches played and 3% of in-game performance measures. Each individual combine test explained <2% of the matches played outcome. Draft selection order demonstrated mixed results for career outcomes relative to playing position. For instance, key forwards and draft selection order were observed as a slight negative relationship using the AFL Player Ranking points career outcome measure. These findings indicate that the AFL draft combine is a poor measure for informing talent selection, thus providing minimal utility for the practices investigated in this study.

Same-Day Vs Consecutive-Day Precision Error of Dual-Energy X-Ray Absorptiometry for Interpreting Body Composition Change in Resistance-Trained Athletes

The application of dual-energy X-ray absorptiometry (DXA) in sport science settings is gaining popularity due to its ability to assess body composition. The International Society for Clinical Densitometry (ISCD) recommends application of the least significant change (LSC) to interpret meaningful and true change. This is calculated from same-day consecutive scans, thus accounting for technical error. However, this approach does not capture biological variation, which is pertinent when interpreting longitudinal measurements, and could be captured from consecutive-day scans. The aims of this study were to investigate the impact short-term biological variation has on LSC measures, and establish if there is a difference in precision based on gender in a resistance-trained population. Twenty-one resistance-trained athletes (age: 30.6 ± 8.2 yr; stature: 174.2 ± 7.2 cm; mass: 74.3 ± 11.6 kg) with at least 12 mo consistent resistance training experience, underwent 2 consecutive DXA scans on 1 d of testing, and a third scan the day before or after. ISCD-recommended techniques were used to calculate same-day and consecutive-day precision error and LSC values. There was high association between whole body (R² = 0.98-1.00) and regional measures (R² = 0.95-0.99) for same-day (R² = 0.98-1.00), and consecutive-day (R² = 0.95-0.98) measurements. The consecutive-day precision error, in comparison to same-day precision error, was significantly different (p < 0.05), and almost twice as large for fat mass (1261 g vs 660 g), and over 3 times as large for lean mass (2083 g vs 617 g), yet still remained within the ISCD minimum acceptable limits for DXA precision error. No whole body differences in precision error were observed based on gender. When tracking changes in body composition, the use of precision error and LSC values calculated from consecutive-day analysis is advocated, given this takes into account both technical error and biological variation, thus providing a more accurate indication of true and meaningful change.

Interpretation of Dual-Energy X-Ray Absorptiometry-Derived Body Composition Change in Athletes: A Review and Recommendations for Best Practice

Dual-energy X-ray absorptiometry (DXA) is a medical imaging device which has become the method of choice for the measurement of body composition in athletes. The objectives of this review were to evaluate published longitudinal DXA body composition studies in athletic populations for interpretation of "meaningful" change, and to propose a best practice measurement protocol. An online search of PubMed and CINAHL via EBSCO Host and Web of Science enabled the identification of studies published until November 2016. Those that met the inclusion criteria were reviewed independently by 2 authors according to their methodological quality and interpretation of body composition change. Twenty-five studies published between 1996 and November 2016 were reviewed (male athletes: 13, female athletes: 3, mixed: 9) and sample sizes ranged from n = 1 to 212. The same number of eligible studies was published between 2013 and 2016, as over the 16 yr prior (between 1996 and 2012). Seven did not include precision error, and fewer than half provided athlete-specific precision error. There were shortfalls in the sample sizes on which precision estimates were based and inconsistencies in the level of pre-scan standardization, with some reporting full standardization protocols and others reporting only single (e.g., overnight fast) or no control measures. There is a need for standardized practice and reporting in athletic populations for the longitudinal measurement of body composition using DXA. Based on this review and those of others, plus the official position of the International Society for Clinical Densitometry, our recommendations and protocol are proposed as a guide to support best practice.

A comparison of the physiological profiles of elite Gaelic footballers, hurlers, and soccer players

BACKGROUND

Gaelic football, soccer, and hurling are prominent field games in Ireland and involve participants undertaking a variety of playing tasks and skills which place various physiological demands on the participants. The aim of this study was to evaluate and compare the mid-season physiological profiles of elite players.

METHODS

Physiological assessment was carried out on 29 inter-county Gaelic footballers, 30 inter-county hurlers, and 21 League of Ireland soccer players.

RESULTS

Significant differences were reported for % body fat (p<0.05), aerobic capacity (p<0.05), flexibility (p<0.05), upper body strength (p<0.05), upper body strength endurance (p<0.05), abdominal endurance (p<0.05), and speed endurance (p<0.05), while there were no differences recorded for height, weight, or speed levels. A relatively heterogeneous body size is evident for all three sports. Soccer players had lower body fat levels, greater aerobic capacity, greater strength endurance, and greater flexibility compared to both Gaelic footballers and hurlers, possibly due to specific training and conditioning programmes or physical adaptation to match play The greater strength of both Gaelic footballers and hurlers and the superior speed endurance levels of Gaelic footballers also reflect the physical nature of the sports. Similar speed levels amongst all three sports reflect the importance of speed for performance.

CONCLUSIONS

The various physiological attributes for Gaelic football, soccer, and hurling reflect the physical requirements for success and participation in each of these field games.

Physical and fitness characteristics of successful Gaelic footballers

Anthropometric and fitness observations were made on 32 members of a top level Gaelic football squad that reached the All Ireland final in the year in which these measurements were taken. The subjects were found to be large and well muscled with a mean somatotype of 2.6:5.6:3.1 (endomorphy:mesomorphy:ectomorphy). Body fat content of the whole squad averaged 15.0% but the most successful group of players averaged 12.4%. The body mass index (BMI) of the group was high and averaged 24.7 km.m-2. This group of Gaelic footballers was found to be taller and heavier than top level soccer players but smaller than Australian rules and American footballers. At 58.6 ml.min-1.kg-1 maximum oxygen uptake (VO2max) was higher than that reported for rugby players and American footballers and is probably similar to that of professional soccer players. Scores on three lung function tests: (1) forced vital capacity (FVC), (2) forced expiratory volume during 1 s (FEV1), and (3) peak expiratory flow rate (PEFR) were between 112% and 115% of the values predicted from height and age. There were wide variations in flexibility among the members of the group, the best individuals being as flexible as elite track and field athletes while the worst were less flexible than untrained subjects. Vertical jump scores were high and averaged 503 mm. The fitness observations made on this group of elite Gaelic footballers showed that they were not only fitter but more homogeneously fit than rugby players and American footballers and their fitness was generally similar to that reported for professional soccer players.

Seasonal changes in body composition in Australian Rules footballers

Anthropometric measurements were collected from a group of Australian Rules footballers at the start and end of the competitive season. Eighty-nine players were studied, drawn from a top level professional league team, a second level association team and an A-grade amateur association team. Changes in the physical profile of these players during the season were observed. A small but significant gain in fat-free body mass in the top level players was observed (0.9 kg, p less than 0.01), but no change in body fat. The intermediate level players showed no significant change in body mass and a tendency toward a slight loss in body fat, while the lower level players showed a significant loss in body fat during the season (1.8 kg, p less than 0.001) without significant change in fat-free body mass.