Introduction
Gaelic football is one of 2 national sports of Ireland (28). The premier competition within the Gaelic football calendar is the All Ireland series that runs from May through to September (4). Elite matches are played across 70 minutes with 15 players on each team attempting to outscore one another over the course of the game (28). Players are amateur in nature with a professional ethos, generally completing 3 pitch sessions, 2 gym sessions along with other squad meetings and workshops throughout the course of a week, while attempting to balance a family and working life (4). Gaelic football is a multidirectional sport that requires players to undertake numerous unpredictable bouts of high-intensity exercise that are interspersed by periods of low-intensity exercise (6,25). Throughout the periods of high-intensity exercise, contact between players can be high, while both offensive and defensive skills need to be used at high speed (16,28). These skills include both hand and kick passing, shooting, blocking, tackling, and large amounts of player movement independent of which team controls possession (13,28). High levels of performance are associated with increased fitness characteristics of players (7). It has been previously reported that Gaelic football players have similar fitness characteristics to professional soccer players (28), with estimated V̇o2max values for both Gaelic football (58.8 ml·kg−1·min−1) and soccer (59.4 ml·kg−1·min−1) seen to be similar (32).
Recent advancements in technology have allowed for the appraisal of match-play demands through the use of global positioning system microtechnology (9,15,17,18). These investigations have observed position-specific movement demands during match-play with the middle 3 positional lines, half backs (8,700 m), midfielders (9,523 m), and half forwards (8,952 m) covering more distances than the other 2 respective positions, full backs (6,892 m) and full forwards (7,090 m) with 17% of match-play covered at high speed (>17 km·h−1) (18). Positional variations in match-play performance are understood and displayed in the aforementioned data. However, there is a scarcity of performance characteristic studies completed in Gaelic football. Although previous studies have provided information regarding specific fitness and performance characteristics (21,22,26), there is no contemporary positional data with regard to elite Gaelic football players. An insight into the various positional fitness considerations for Gaelic football would allow practitioners to effectively design particular training regimes to potentially improve competitive performances.
Comparisons of Gaelic Athletic Association (GAA) players with other intermittent team sports such as soccer have shown that V̇o2max values to be similar to those of professional soccer players and rugby union backs. However, sprint performance was greater in both professional codes (6,32). Research into the area of jump performance has provided some information regarding vertical jump height that has been provided for the different positions; however, these data are specific to collegiate players and not elite players. Vertical jump performance was seen to vary from backs (54 cm), midfielders (65 cm), and forwards (56 cm), with these results provided for specific jump test (22). The normative values provided by McIntyre and Hall (22) fail to account for the 5 positional lines within elite Gaelic football. The ever changing nature of elite match-play has resulted in the middle 3 lines of a team having an increased involvement in match-play (17). Understanding each specific line and their characteristics is important for coaches to optimize the preparation of players for elite match-play. Although there is an ever-growing interest worldwide in Gaelic football, research into positional variations and the particular performance characteristics in elite players is deficient. Therefore, the aim of the current study was to evaluate the anthropometric and performance characteristics of elite Gaelic football players with respect to playing position. We hypothesized that the transitional lines of half back, midfield, and half forward would have significantly different anthropometric and performance profiles when compared with other positions of play.
Methods
Experimental Approach to the Problem
To better understand the anthropometric and performance characteristics of elite Gaelic football players, 148 (n = 148) elite Gaelic football players were recruited for the current investigation. All players underwent assessments of anthropometric (height, body mass, sum of the 7 skinfold, and adipose tissue percentage estimates [%AT]) and performance characteristics (counter movement jump [CMJ] height, CMJ peak power, CMJ relative peak power [RPP], squat jump [SJ] height, SJ peak power, SJ RPP, 5-, 10-, and 20-m sprint times [s], and Yo-Yo Intermittent Recovery Test Level 2 [Yo-YoIRT2; m]). Each individual player was categorized based on positional line (28 full backs, 33 half backs, 24 midfielders, 33 half forwards, and 30 full forwards). Before data collection, 30 other subjects completed 2 identical testing sessions that were (separated by 1 week), data from session 1 were compared with session 2, and intraclass correlation coefficients (ICCs) were determined from the results. Data collection was undertaken during the “the early in-season” phase (June 2015) with a total of 5 teams assessed. Both anthropometric and performance tests were performed indoors to avoid any external influence on data collection. All testing took place at a similar time of day (18.00–21.00) across 2 testing days to avoid any circadian variation in performance (30). Participants were advised to abstain from vigorous exercise for 24 hours before the commencement of testing.
Subjects
After ethical approval from the local Research Ethics Committee and signed informed consent was obtained, 148 elite intercounty Gaelic football players (mean ± SD age 26.6 ± 6 years, height 183.7 ± 5.9 cm, and body mass 83.6 ± 8.3 kg) (28 full backs, 33 half backs, 24 midfielders, 33 half forwards, and 30 full forwards) participated in the current investigation. All participants were competing in the All-Ireland Senior football championship underwent measurements of anthropometric (height [cm], body mass [kg], sum of the 7 skinfold [mm], and %AT) and performance characteristics (CMJ height [cm], CMJ peak power [W], CMJ RPP [W·kg−1], SJ height [cm], SJ peak power [W], SJ RPP [W·kg−1], 5-, 10-, and 20-m sprint times [s], and Yo-YoIRT2 [m]). Each individual player was categorized into the line of the field in which they play to allow comparison across different positions. The study was approved by the ethics committee in the Institute of Technology, Tallaght, Dublin.
Procedures
Anthropometric measurements were made before the commencement of the performance evaluation (Figure 1). Height and body mass measurements were taken using a Seca Stadiometer and weighing scales (Seca Instruments Ltd., Hamburg, Germany), respectively. Estimation of adipose tissue mass was conducted by measurement in millimeters of the 7 skinfold sites (triceps, bicep, subscapular, abdominal, supraspinale, thigh, and calf) using the Harpenden skinfold Caliper (Harpenden Instruments Ltd., Warwickshire, United Kingdom) following the standards of the International Society for the Advancement of Kinanthropometry (ISAK) (19). The %AT was calculated using the Reilly equation (29) and assessed by a Level 2 ISAK-qualified tester. The error of measurement was taken from all subjects and calculated for all anthropometric measurements and was less than 3% which is an acceptable measurement error (1).
Performance
Counter movement jump and SJ for maximal jump height were measured using a jump assessment system (Optojump, Bolzano, Italy). The CMJ and SJ peak power (PP) and RPP were calculated using the equation of Sayers et al. (31). The sprint times (s) of each participant were measured over 20 m with timing gates located at 5, 10, and 20 m (Microgate, Bolzano, Italy). Furthermore, players completed the Yo-Yo Intermittent Recovery Test (Yo-YoIRT2) to assess an individual's ability to perform repeated bouts of high-intensity exercise with a high contribution from the body's anaerobic system and have been shown to be a reliable measure of changes in performance (3,23,24). The assessment of vertical jump power and speed was conducted before the Yo-YoIRT2.
Statistical Analyses
All data are reported as mean and SDs unless stated. Data were calculated for all players with respect to the positional group with 95% conference intervals. All data were tested for normality, and all data that did not pass tests were removed from statistical analysis. A univariate analysis of variance along with Scheffe's post hoc test was performed to determine whether there was variation in position (dependent variable) present within any of the anthropometric and performance characteristics (independent variables), with statistical significance set at <0.05. Specifically, Hopkins reliability spreadsheet was used to calculate for ICC values for the specific performance tests used in the profiling of the participants and followed on previous research for this statistical analysis (2,12). The ICCs for the test-retest reliability were 0.96, 0.90, 0.92, 0.95, 0.95, and 0.90 for CMJ, SJ, sprint time over 5, 10, and 20 m, and Yo-YoIRT2, respectively. All statistical analysis was performed using the Statistical Package for Social Sciences software (SPSS Version 23.0, Chicago, IL, USA).
Results
Anthropometric Characteristics
The mean height and body mass of all players were 183.7 ± 5.9 cm and 83.6 ± 8.3 kg, respectively. There was a significant effect detected for the positions when analyzed for height (F4,143 = 2.940; p = 0.023) but not for body mass (F4,143 = 2.139; p = 0.079) (Table 1). The sum of the 7 skinfold sites and adiposity were 81.3 ± 22.9 mm and 11.3 ± 1.7 %AT, respectively. Significant differences (p ≤ 0.05) were detected across the individual positions for both sum of skinfolds (F4,143 = 4.890; p = 0.000) and adiposity (F4,143 = 6.581; p = 0.000). Scheffe's post hoc analysis showed that both half backs (72.9 ± 14.8 mm; p = 0.005) and half forwards (77.0 ± 17.1 mm; p = 0.040) possessed significantly lower sum of the 7 skinfolds compared with full forwards (94.6 ± 30.2 mm). Significant differences were observed in %AT across position. Half backs (10.5 ± 1.2 %AT; p = 0.001), midfielders (10.9 ± 1.2 %AT; p = 0.035), and half forwards (10.9 ± 1.4 %AT; p = 0.021) showed a significantly lower %AT to full forwards (12.3 ± 2.1 %AT). Half backs were also shown to have a significantly lower adiposity level compared with the full backs (11.9 ± 2.0 %AT; p = 0.040).
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Table 1.: The positional anthropometric and performance characteristics of elite Gaelic football players.*†
Performance Characteristics
The mean values for all players for SJ height, SJ PP, and SJ RPP were 36.1 ± 4.9 cm, 3,923 ± 501 W, and 46.9 ± 3.6 W·kg−1, respectively. Significant differences across the positions were observed within SJ (F4,143 = 3.113; p = 0.017), SJ PP (F4,143 = 2.449; p = 0.049), and SJ RPP (F4,143 = 2.816; p = 0.028). For SJ height, full forwards were shown to have a significantly higher SJ height (37.5 ± 5.6 cm; p = 0.036) than midfielders (33.3 ± 3.7 cm). The mean values for CMJ height, CMJ PP, CMJ RPP were 38.0 ± 5.1 cm, 4,040 ± 510 W, and 48.3 ± 3.7 W·kg−1, respectively. Significant differences were observed across the individual positions for the 3 variables of CMJ height (F4,143 = 3.597; p = 0.008), CMJ PP (F4,143 = 3.142; p = 0.016), and CMJ RPP (F4,143 = 3.211; p = 0.015). Full forwards (40.0 ± 5.8 cm; p = 0.013) were shown to have a significantly higher CMJ height compared with the midfielders (35.0 ± 4.0 cm). Full forwards (49.6 ± 4.1 W·kg−1; p = 0.024) were also shown to have a significantly greater RPP for CMJ than the midfielders (46.2 ± 2.9 W·kg−1). The mean sprint times for 5-, 10-, and 20-m sprints for all players were 1.10 ± 0.11, 1.82 ± 0.12, and 3.09 ± 0.16 seconds, respectively. A nonsignificant difference was observed across the individual positions for each of the 3 sprint variables, 5 (F4,143 = 1.665; p = 0.164), 10 (F4,143 = 0.612; p = 0.655), and 20 m (F4,143 = 0.588; p = 0.672). Figure 2 shows the Yo-YoIRT2 with respect to position. The mean distance covered in the Yo-YoIRT2 for all players was 1,587 ± 298 m, with significant differences observed across the positions (F4,143 = 15.999; p = 0.000).
Figure 1.: Schematic of testing battery running order during the initial testing period. CMJ = counter movement jump; SJ = squat jump.
Figure 2.: Yo-Yo Intermittent Recovery Test Level 2 (Yo-YoIRT2) distance in elite Gaelic football with regard to position (mean ± SD). *Significantly different from full backs and full forwards (p ≤ 0.05).
Discussion
The aim of the current investigation was to evaluate the variation in anthropometric and performance characteristics of elite Gaelic football players with respect to playing position. The data are the first to offer a full contemporary profile of anthropometric and performance characteristics of elite Gaelic football players with regard to playing position. Specifically, we observed that the 3 middle positional lines on the field have a greater Yo-YoIRT2 performance compared with full backs and full forwards. Furthermore, full forwards were shown to have a greater %AT compared with the 3 middle positional lines. Variations in jump performance were observed between midfielders and full forwards, with the latter having a significantly greater jump performance profile. The current data allow specific training regimes to be measured against the current data set to best prepare players for the demands of competitive match-play.
Anthropometric characteristics such as height may vary from position to position because of tactical motives (8). The values obtained in the current study for stature show that Gaelic football players are taller but leaner with regard to %AT than previously reported (22). It must be noted that the game of Gaelic football has evolved in recent years; both the tactical element and player development have increased greatly through the advent of strength and conditioning programs making the comparison to the previous research difficult (27). Limited variation was observed across each of the 5 positions in the present study with regard to stature. These observations are in agreement with Collins et al. (8), who observed a relative homogeneity within positions for stature of the players or body mass for elite hurling players. Furthermore, half backs, midfielders, and half forwards had lower %AT when compared with the full forwards (Table 1). Interestingly, our data are in contrast to previously reported literature on Gaelic football players with the current %AT lower across positional lines than previously reported (6,21). Although %AT in the current study is lower than previous literature, the values reported are higher than those observed for Australian football players (5), but similar to elite soccer players (11). The lower levels of %AT in Australian football players can be contributed to the professional nature of the sport compared with the amateur nature of Gaelic football, with players tending to hold down a full-time occupation outside the sport (4). The higher %AT for full forward players could potentially be attributed to the less distance that is covered in a match compared with all other positional lines on the field of play (18).
Gaelic footballers are required to contest numerous duels throughout a match that will determine who gains possession with a large number of these potentially being aerial duels. In both vertical jump assessments (CMJ and SJ), full forwards were observed to significantly outperform the midfielders. Although a surprising finding, this may be related to a reduction in one-on-one aerial duels for midfield players in match-play because of the advent of the short kick-out (11). This in turn has resulted in an increase in direct aerial ball being played into full-forward areas increasing the requirement of these players to possess such characteristics for jump height. Similar results are evident in hurling, with backs and forwards outperforming midfielders during jump assessments (8). Both SJ and CMJ are methodologies widely used to determine the jump performance in team sports; however, a majority of the jumps that players conduct within a Gaelic football match will be preceded by an initial run-up to generate more height for aerial contests. This may question the suitability of such tests for the assessment of lower limb explosive qualities within Gaelic football (10,20,33). Future research should aim to assess the usefulness of such assessments within this population, given the intricacies of match-play jump performance in elite Gaelic football.
Our data showed that across velocity variables (5, 10, and 20 m), there was a nonsignificant difference between position. The current observation was expected and in line with match-play research that has shown that no significant differences exist between positional lines for maximal velocity capabilities (17,18). Furthermore, these results are in agreement with velocity variables observed in hurling cohorts (8). The sport of Gaelic football has been evolving from year to year with increasing demands for high-intensity distance across all positional lines (8,17,18). These increased demands result in players needing to be capable of repeating numerous high-intensity bursts throughout match-play (16,17). Previously, Le Rossignol et al. (14) have shown that repeated sprint ability and an adequate aerobic capacity are critical physical qualities for performance in match-play with the number of possessions gained related to improved performance in a 20-m sprint test. Future research in elite Gaelic football should aim to assess the relationships between performance tests and match-play involvements and outcomes to recommend best practice with regard to a suitable testing battery for Gaelic football cohorts.
When intermittent exercise capacity was considered, significant differences in Yo-YoIRT2 performance across all positions were evident, with a bell-shaped curve for the distance observed (Figure 2). Interestingly, the intermittent exercise capacity of elite Gaelic football players is similar to the observed match-play running performances of elite Gaelic football players (17,21). When comparing Yo-YoIRT2 across sports, Australian Football League (AFL) players have a considerably lower Yo-YoIRT2 profile (23). Given the similarities between both sports (28), future research should aim to compare anthropometric and performance profiles of elite Gaelic football and Australian football players. With regard to positional differences, the middle 3 positional lines, half backs (1,682 ± 273-m), midfielders (1718 ± 251-m), and half forwards (1747 ± 243-m), were able to cover significantly greater distances than both full backs (1,428 ± 208-m) and full forwards (1,352 ± 277 m). These findings can be related to these positions being the transitional lines of play in Gaelic football resulting in these lines covering increased distances in match-play and therefore requiring increased intermittent exercise capacity to meet the requirements of match-play (17). The findings observed here corresponded with conclusions from McIntyre and Hall (21), who found that midfielders possessed a greater V̇o2max characteristic when compared with backs and forwards. However, the study failed to differentiate across the 5 positional lines of play. The current data further endorse the need for certain players on the field of play to require greater intermittent exercise capacity to deal with the particular demands associated with each position of play. Performance characteristics, exercise capacity, and running performance evaluations have recently become increasingly popular in Gaelic football as part of player monitoring throughout the course of the season. It has only been relatively recently that the values within elite Gaelic football have been published for the different positional lines of the field with respect to match running demands (15). The current investigation builds on these data and provides normative data with regard to the positional performance profile associated with Gaelic football. Practitioners can now apply these data to develop the required training regimen to best fit the performance profile of Gaelic football.
To conclude, the current investigation supplies for the first time normative data on elite Gaelic football players with regard to positional anthropometric and performance characteristics. Observations were made regarding significant differences in both performance and anthropometric characteristics with respect to position. Intermittent exercise capacity differences are seen to be present in the middle 3 lines of the field within this cohort compared with the full backs and full forwards, further outlining the need for specific training regimes in elite Gaelic football. Along with variations in performance characteristics, differences have been observed in other areas of player evaluation which in turn will allow coaches to adequately prepare players for match-play based on the positional characteristics.
Practical Applications
The normative data presented in the current study can be used by coaches evaluating both anthropometric and performance characteristics of elite players in the sport of Gaelic football. The main findings from the study show differences in %AT, sum of skinfolds (mm), Yo-YoIRT2, and jump performance measures across positions in Gaelic football. With regard to aerobic performance, a positional hierarchy was present, with the middle 3 “transitional lines” having the highest performance. Therefore, the information provided within the current study can help prepare coaches assess their teams' anthropometric and performance characteristics. Combining all the knowledge that is now available within the sport, coaches and practitioners should have a greater understanding on how to prepare their players for the impending competition demands across each distinctive position using specific training and drills for positional differences. The information provided in the study can be exploited by those with ambitions to play elite level Gaelic football; the normative values can be seen at values that they may strive to achieve to “break in” to the elite panel. Applied practitioners can assess and evaluate Gaelic football players based on the normative data provided by this study. Coaches should be aware of the specific positional profiles present across Gaelic football cohorts and use this information to plan training appropriately to maximize training adaptations through the implementation of the most effective training plans.
References
1. Atkinson G, Reilly T, Marfell-Jones M. What is this thing called measurement error. In: Kinathropometry VIII: Proceeding of the 8th International Conference of Kinathropometry (ISAK), London, UK: Routledge. 2013. pp. 3–13.
2. Atkinson G, Nevill AM. Statistical methods for assessing measurement error (reliability) in variables relevant to sports medicine. Sports Med 26: 217–238, 1998.
3. Bangsbo J, Iaia FM, Krustrup P. The Yo-Yo intermittent recovery test. Sports Med 38: 37–51, 2008.
4. Beasley KJ. Nutrition and Gaelic football: Review, recommendations, and future considerations. Int J Sport Nutr Exerc Metab 25: 1–13, 2015.
5. Bilsborough JC, Kempton T, Greenway K, Cordy J, Coutts AJ. Longitudinal changes and seasonal variation in body composition in professional Australian football players. Int J Sports Physiol Perform 12: 10–17, 2017.
6. Brick N, O'Donoghue P. Fitness profiles of elite players in hurling and three football codes: Soccer, rugby union and Gaelic football. Science and Football V 172, 172–178, 2005.
7. Castagna C, Impellizzeri F, Cecchini E, Rampinini E, Alvarez JCB. Effects of intermittent-endurance fitness on match performance in young male soccer players. J Strength Cond Res 23: 1954–1959, 2009.
8. Collins DK, Reilly T, Morton JP, McRobert A, Doran DA. Anthropometric and performance characteristics of elite hurling players. J Athl Enhancement 3: 6, 2014.
9. Collins DK, Solan B, Doran DA. A preliminary investigation into high-intensity activity during elite Gaelic football match-play. J Sports Ther 10, 1–5, 2013.
10. Cronin JB, Hansen KT. Strength and power predictors of sports speed. J Strength Cond Res 19: 349–357, 2005.
11. Daly D, Donnelly R. Data analytics in performance of kick-out distribution and effectiveness in senior championship football in Ireland. J Sports Anal, 2016. Epub ahead of print.
12. Johnston RJ, Watsford ML, Pine MJ, Spurrs RW, Murphy AJ, Pruyn EC. The validity and reliability of 5-Hz global positioning system units to measure team sport movement demands. J Strength Cond Res 26: 758–765, 2012.
13. Keane S, Reilly T, Hughes M. Analysis of work rates in Gaelic football. Aus J Sports Sci 25: 100–102, 1993.
14. Le Rossignol P, Gabbett TJ, Comerford D, Stanton WR. Repeated-sprint ability and team selection in Australian football league players. Int J Sports Physiol Perform 9: 161–165, 2014.
15. Malone S, Collins DK, McRobert AP, Doran DA. A comparison of work rate displayed by elite and sub elite hurlers during match play. Paper presented at the annual congress of the British Association of Sport and Exercise Sciences. December, Burton, England, 2014.
16. Malone S, Roe M, Doran DA, Gabbett TJ, Collins K. High chronic training loads and exposure to bouts of maximal velocity running reduce injury risk in elite Gaelic football. J Sci Med Sport 20: 250–254, 2017.
17. Malone S, Solan B, Collins KD, Doran DA. Positional match running performance in elite Gaelic football. J Strength Cond Res 30: 2292–2298, 2016.
18. Malone S, Solan B, Collins K. The running performance profile of elite Gaelic football match-play. J Strength Cond Res 31: 30–36, 2017.
19. Marfell-Jones M, Olds T, Stewart A, Carter L. International Standards for Anthropometric Assessment. Potchefstroom, South Africa. International Society for the Advancement of Kinanthropometry, 2006.
20. McGuigan MR, Cormack S, Newton RU. Long-term power performance of elite Australian rules football players. J Strength Cond Res 23: 26–32, 2009.
21. McIntyre MC, Hall M. Physiological profile in relation to playing position of elite college Gaelic footballers. Br J Sports Med 39: 264–266, 2005.
22. McIntyre MC. A comparison of the physiological profiles of elite Gaelic footballers, hurlers, and soccer players. Br J Sports Med 39: 437–439, 2005.
23. Mooney M, O'Brien B, Cormack S, Coutts A, Berry J, Young W. The relationship between physical capacity and match performance in elite Australian football: A mediation approach. J Sci Med Sport 14: 447–452, 2011.
24. Oberacker LM, Davis SE, Haff GG, Witmer CA, Moir GL. The Yo-Yo IR2 test: Physiological response, reliability, and application to elite soccer. J Strength Cond Res 26: 2734–2740, 2012.
25. O'Donoghue PG, Donnelly O, Hughes L, McManus S. Time–motion analysis of Gaelic games. J Sports Sci 22: 255–256, 2004.
26. Reeves S, Collins K. The nutritional and anthropometric status of Gaelic football players. Int J Sport Nutr Exerc Metab 13: 539–548, 2003.
27. Reilly B, Akubat I, Lyons M, Collins DK. Match-play demands of elite youth Gaelic football using global positioning system tracking. J Strength Cond Res 29: 989–996, 2015.
28. Reilly T, Collins K. Science and the Gaelic sports: Gaelic football and hurling. Eur J Sport Sci 8: 231–240, 2008.
29. Reilly T, George K, Marfell-Jones M, Scott M, Sutton L, Wallace JA. How well do skinfold equations predict percent body fat in elite soccer players? Int J Sports Med 30: 607–613, 2009.
30. Reilly T, Brooks GA. Exercise and the circadian variation in body temperature measures. Int J Sports Med 7: 358–362, 1986.
31. Sayers SP, Harackiewicz DV, Harman E, Frykman PN, Rosenstein MT. Cross-validation of three jump power equations. Med Sci Sports Exerc 31: 572–577, 1999.
32. Strudwick A, Reilly T, Doran D. Anthropometric and fitness profiles of elite players in two football codes. J Sports Med Phys Fitness 42: 239, 2002.
33. Young W, Cormack S, Crichton M. Which jump variables should be used to assess explosive leg muscle function. Int J Sports Physiol Perform 6: 51–57, 2011.
