Gaelic football has been played in Ireland for centuries, yet research relating to the game remains limited (21). The game is played between 2 teams of 15 players on a natural playing surface. Guidelines from the governing body of Gaelic games (Gaelic Athletic Association [GAA]) state that pitches must be between 130 and 145 m in width and 80–90 m in length. Matches consist of two 35-minute halves, with time often added on for injuries and stoppages. The 2 major competitions that teams compete for are the National Football League (NFL) and the All-Ireland Senior Football Championship. The NFL begins in January or February each year, with the finals held in April. There are 4 divisions in the NFL, each containing 8 teams. The championship is split into 3 stages; the provincial championship, the All-Ireland qualifiers, and the All-Ireland championship. Provincial championships are completed in a straight knockout (single-elimination) format, beginning in May and continuing through to July. If a team loses in the provincial championship, they drop into the All-Ireland qualifiers. The All-Ireland qualifiers are also of knockout format and last from June to August. The 4 teams that progress through the All-Ireland qualifiers play the 4 winners of the provincial championships in the All-Ireland championship quarter-finals.
Elite Gaelic football players will typically cover 8,160–9,222 m in a competitive match, with 1,695–1,731 m of that being run at high speed (≥17 km·h−1; m) (9,21,22). To date, the only factors that are known to influence running performance in Gaelic football are playing position, team, match outcome, and match quarter (21,25). In Gaelic football, there are 5 positional lines in addition to the goalkeeper; full back, half back, midfield, half forward, and full forward (21). Typically, midfield players will cover a greater total distance and high-speed distance than all other positions (p ≤ 0.001) (21). This is likely due to the fact that midfield players perform a major role in both attacking and defending. In other sports, a number of contextual factors have been identified as possibly impacting physical performance (28). These factors include pitch size (15), match location (5), level of competition (34), opposition quality (12), match importance (2), weather (35), score line (5), and time of season (26). Preliminary investigations in Gaelic football have shown that higher rated teams will run greater distances than lower rated teams (24). In Gaelic football, most teams prioritize the All-Ireland championship over the NFL (23). It is currently unclear whether this impacts running performance as the competition changes from the NFL to the championship.
In soccer, total distance and high-speed distance are greater at the end of the season in comparison with the start or the middle of the season (26,29). This is likely due to training adaptations, an increase in fitness levels, opposition quality, and match strategy (6). Caldwell and Peters (4) reported significantly higher Vo2max values in soccer players at the end of the season as opposed to at the start of a season. During the off-season, a detraining effect can result in lower aerobic fitness levels, slower sprint times, and increased body fat percentage (27,30). As a result of lower aerobic fitness levels, it is not unreasonable to say that player's physical capacity in matches may be reduced. In Gaelic football, the off-season for county teams is determined by when they are knocked out of the All-Ireland championship. The length of the off-season can range from 12 weeks to 6 months, depending on how successful a team is. During the majority of this time, players will continue playing with their subelite club teams.
Australian football players run on average 190 m more at high speed (≥14.4 km·h−1) in games in the final stage of the season than they do in games in the earliest part of the season (32). In the same sport, match-play loads, measured in arbitrary units, have been observed to increase from preseason to in-season (33). This coincides with a decrease in training load during the in-season (33). A similar trend is evident in both rugby league (13) and rugby union (11), where training loads are reduced during the competitive part of the season. However, in Gaelic football, there is no significant difference in average weekly training loads between preseason, early in-season, and late in-season (19). It is not currently known whether match-play running performance in Gaelic football is affected by the time of season. Knowing such information would be of huge benefit to strength and conditioning coaches for the planning of training loads. If running demands are different across the season, training blocks can be planned to ensure that player's fitness levels are peaking at the times where match-play demands are greatest. Anecdotally, it is said that match-play running performance increases across the year with this potentially related to competition changes from the league to the championship (23). Therefore, the aim of the current research was to examine whether the time of season influences match-play running performance in elite Gaelic football players.
Experimental Approach to the Problem
The current observational study was designed to examine the seasonal variation in match-play running performance of elite Gaelic football players using portable global positioning systems (GPS) technology. Player movements were monitored in competitive Gaelic football matches over a 5-year period (2012–2016). At the time of data collection, all teams participated in the top 3 divisions of the National Football League. After the exclusion of players who did not complete the entire game, a total of 780 full data sets from 95 matches were available for data analysis. Match data were collected from the first game of the season (round 1 of the National Football League) to the last game of the season (the All-Ireland football championship final). All matches took place between the hours of 13:00 and 20:00. Temperatures at the time of matches ranged from 11 to 22° C.
Elite male Gaelic football players (n = 93, aged 26.2 ± 2.8 years [18 years and older]) from 5 different intercounty teams participated in this study. Participants were selected on the basis that they were chosen to be a part of their respective county squad in that given year. Informed consent and institutional ethical approval from the Institute of Technology Tallaght were obtained before the commencement of this investigation. Once this was confirmed, all participants were issued with an information sheet stating the goals of this research and the requirements on them as participants. Written consent and a medical declaration were obtained from each participant as per institutional ethical guidelines and subject characteristics were measured mean ± SD.
The GPS devices used for data collection sample at 4 Hz (VX Sport). The validity and reliability of the selected GPS model have been established previously (3,18). Test-retest (7 days apart) reliability of the devices suggest that as running speed increases, so too does the variability in the data (18). The coefficient of variation (CV) for the devices was less than 5% for total distance, low-speed distance, maximum speed, and average speed; however, high-speed distance had a CV of 8 ± 2.5% (95% confidence interval [CI]) (18). The GPS devices were turned on at least 15 minutes before each match to establish a satellite lock (17). Each player was equipped with a chest harness for the GPS device. The GPS device was then placed in an upright position between the shoulder blades. Individual player data were extracted from the GPS devices after each game using the VX Sport software (Firmware 4.01.2.0; VX Sport). The data files were trimmed to exclude any data points from before the start of the game, half time, and after the final whistle. The VX Sport software was then used to split the match data into 4 quarters. All data were exported into a custom spreadsheet (Excel; Microsoft, Redmond, WA, USA). Total distance (m), high-speed distance (≥17 km·h−1; m), and playing time were noted for all players. The high-speed threshold of ≥17 km·h−1 was used to keep consistent with previous research in Gaelic football (8,21,22). Match date was recorded for all games during the data collection phase. Time of season was determined by the month in which each match was played (January–September). Percentage high-speed distance was calculated by dividing the total distance by high-speed distance.
All running performance data were anonymized before analysis as per institution guidelines. The assumptions of normality were assessed before commencement of the statistical analysis. Statistical analyses were performed using SPSS for Mac (version 16.0; SPSS, Inc., Chicago, IL, USA). Data are presented as mean values, SDs, and 95% CIs, unless otherwise stated. Statistical significance was accepted at α ≤ 0.05. One-way analyses of variance (ANOVAs) were conducted to examine the effect of month of year on total distance, high-speed distance, and percentage high-speed distance. A 1-way ANOVA with repeated measures was performed to examine the high-speed distance difference across quarters for month of year. The partial eta-squared (η2) value was used as a measure of effect size (7). Effect size benchmarks specific to partial eta-squared were used to divide effects into small (0.0099–0.0587), medium (0.0588–0.1378), and large (>0.1379) (31).
Time of season had a significant impact on total distance covered in matches (p ≤ 0.001 partial η2 = 0.148), with a large effect size evident. Players were observed to run a significantly higher distance in August (p ≤ 0.001) and September (p ≤ 0.001) in comparison with any other month (Figure 1).
Time of season had a significant impact on high-speed distance (p ≤ 0.001 partial η2 = 0.105), with a medium effect size evident. Again, August (p = 0.002) and September (p ≤ 0.001) were significantly different from all other months for high-speed distance. The percentage distance covered at high-speed was observed to increase significantly over the course of the season (p = 0.041 partial η2 = 0.021). Only small effects were observed between months for the percentage of distance covered at high speed (1).
Month of season and match quarter had a significant interaction with high-speed distance (p ≤ 0.001 partial η2 = 0.106). A significant difference was evident across quarters for high-speed distance (p ≤ 0.001 partial η2 = 0.043). All quarters were considerably different (p ≤ 0.001) from each other for high-speed distance apart from quarters 2 and 3.
The aim of the current study was to examine the effect of time of season on running performance. This study is the first of its kind in Gaelic football. The major finding of this research is that time of season has a large effect (partial η2 = 0.148) on total distance and a medium effect (partial η2 = 0.105) on high-speed distance completed during elite Gaelic football match-play. Running performance was significantly increased in August and September in comparison with every other month. Time of season also had a small effect on the high-speed distance covered per match quarter. These findings may have significant effects on training periodization in Gaelic football.
Our findings are in line with other sports because it shows that the running performance increases as the season progresses (26,29,32). Although comparisons can be made with other sports, it has to be pointed out that Gaelic football remains an amateur sport (1). Players were observed to run significantly greater total distance and high-speed distance in August and September in comparison with any other month (p ≤ 0.002). This coincides with the quarter-finals of the All-Ireland championship, which usually begins in the first week of August each year. One potential explanation for the increase in physical running performance may be due to the higher quality of opposition in the latter stages of the competition (6,24). In the provincial championship, teams are divided by geography and not by quality, whereas the qualifiers are a mix of teams who have been beaten in the provincial stages (23). The All-Ireland series, however, consists of 8 teams, 4 who have only been beaten once and 4 who are unbeaten.
The division, in which a team plays in the league, is generally a reflection of their quality. Given that running performance is much lower during the league than the latter stages of the championship, there are perhaps more factors influencing running performance other than opposition quality (24,28). Teams generally prioritize the championship over the league, using the league as a chance to trial new players and tactical systems (23). Gaelic football players with less intercounty experience will generally not be able to sustain the same training loads as their more experienced counterparts, potentially affecting their running performance (19). Given that the off-season can be long for county teams, detraining may have an effect on the early months of the season. In a bid to maintain its amateur status and prevent burnout, the GAA implements a 3-month collective training ban in the off-season. Because the running performance increases as the season goes on, many teams will never reach the physical fitness levels required to compete in August and September (4). If they are knocked out before this, they will have likely have lower baseline fitness levels in addition to having a longer off-season. It poses the question of whether weaker county teams should continue training even after they are knocked out to bridge the gap in physical fitness to the stronger teams.
An interaction between time of season and match quarter was observed for high-speed running. The amount of distance covered at high speed during the fourth quarter in August (478 ± 237 m) and September (500 ± 219 m) is, in fact, higher than any other quarter in any other month. A drop-off in the fourth quarter is evident for every month, supporting previous research studies (20). Aside from the obvious fatigue and conditioning explanation, this drop-off could also be attributed to pacing. In an attempt to save energy, player's subconscious thought processes often take over, influencing their on-field movements (10). With the difference in running performance across the year, it raises the question whether there is a “seasonal pacing” (16) effect because teams save their energy for the more important matches in the All-Ireland championship. Percentage of high-speed distance was affected by time of season (p = 0.041 partial η2 = 0.021); however, no significant month-month differences were reported. Although not significant, the results in Table 1 show a 3% increase from January to August and September for the percentage of high-speed distance. This is reflective of the changes in match-play demands as the season progresses.
There is an almost linear upward trend for both total distance and high-speed distance across the season. The lowest month for total distance was May, which could be a reflection of the fact that traditionally weaker teams often play in the preliminary stages of their respective provincial championships at this stage of the season (24). Another potential reason for this dip in physical performance could be the fact that teams are using this period as another high-volume training block, similar to what they would have performed in preseason. Previous research relating to seasonal training loads in Gaelic football reported no significant difference in average weekly training loads between preseason, early in-season, and late in-season (19). This is surprising given that in the current study, it was shown that match-play running demands increase as the season goes on. The same study shows that a similar acute:chronic workload ratio has a far greater odds risk of injury late in-season in comparison with early in-season. This is perhaps due to the increase in match-play demands in the final months of the season, with training load not changing to reflect the increased strain on players. Further research is needed to investigate the effect of training load on match running performance.
This study examines just 1 contextual factor that influences running performance. Recent research in Gaelic football has shown that contextual factors such as opposition quality, team, and match outcome influence running performance (24), none of which were taken into account in this investigation. It has been suggested that no study can comprehensively control for all factors that affect running performance, but researchers can at least start to establish some sort of hierarchy for these factors (28). Positional differences in Gaelic football are well established (9,21); however, it would be interesting to examine whether the time of season influence on running performance is position specific. Similarly, pitch size and match importance are other factors that could potentially influence running performance. Although this is one of the largest match demands data sets reported in Gaelic football, a much larger data set is needed to perform a multivariate analysis of all the factors that may influence running performance (28). To date, no research study has established a link between running performance and technical performance in Gaelic football. Further investigations should be performed to examine whether technical skill execution is impacted by the increase in running performance over a season. A limitation of this research is that the team training load was not accounted for. This study did neither take into account team differences nor did it examine year-to-year comparisons in running performance. To calculate high-speed distance, all running performed in-match was broken into different speed zones. This approach negates individual differences that may exist between players. Caution must be used in the interpretation of the results for high-speed running because the CV for the selected GPS devices is 8 ± 2.5% for high-speed running (18). The sample rate of the GPS used in this study was 4 Hz, meaning that they sample at 4 times per second. However, in recent years, 20-Hz GPS devices have become available on the market. It has been said that as the sampling rate increases, so too does the validity and reliability of the GPS device (14).
The current investigation is the first to show that time of season influences running performance in Gaelic football. Our results provide teams with benchmarks of physical performance that they may need to produce, should they reach the latter stages of the All-Ireland football championship. A practical application for strength and conditioning coaches is that they can express training and match distances as a percentage of the match demands at different times throughout the year because the demands change across the season. There is a large gap in running performance between the All-Ireland championship, the provincial championship, and All-Ireland qualifiers. The increase in match-play demands across the season means that the optimal time to make substitutions may change based on the time of year. Strength and conditioning coaches should reduce team training loads in the latter stages of the All-Ireland championship when match-play running performance requirements are elevated to increase recovery time and lower the risk of potential injury. Higher physical demands toward the end of the year are perhaps reflective of the greater rest periods between games. The results of this research point to a detraining effect over the off-season. Teams should re-evaluate their training strategies during the off-season in an attempt to reduce the effects of detraining. If teams can manage to more efficiently attain the physical levels that they reach late in-season, running performance should improve at the start of the next season. Whether this would have an influence on the match outcome remains to be seen, but it would mean that teams could focus more on technical and tactical work in the new season.
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