This study examined maximum BiP periods in respect to the physical and technical demands experienced by sub-elite AF players in comparison to whole game and quarter averaged data. As hypothesised, all recorded metrics were significantly greater during maximum BiP phases than those seen across a whole match (Tables 2 and 3). However, in contrast to the hypothesis, no significant differences were noted in maximum BiP phases across the three playing positions.
The values for distance per minute identified within this study were similar to those previously found within maximum periods of play amongst elite level AF players (using the rolling time frame method) [9, 10], indicating that those at the sub-elite level are able to perform similar levels of intermittent high intensity exercise as their elite counterparts. Furthermore, the maximum values for BiP periods were at least comparable, and in some cases greater, to those seen in both professional rugby union  and elite youth soccer players . Although all BiP periods were significantly greater than those recorded across a whole game, some metrics displayed a greater increase. For example, total running distance and PlayerLoad™ per minute were approximately 1.6 to 1.8 times higher during BiP periods, whereas very high-speed running was as much as 17 times greater. This may be indicative of the reduced opportunity for athletes to reach and maintain running speeds > 24 km·h−1 during a match, owing to reduced pitch spaces afforded by opposition players and therefore increasing the demand to perform several changes of direction and collisions , all of which contribute to some form of deceleration and thus reducing maximal running speed. This finding is somewhat corroborated by Wass and colleagues  who found relative high-speed (19.8–25.1 km·h−1) running performed during BiP periods to show a larger difference than relative distance when compared to averaged data in a population of academy soccer players.
These values reported for maximum BiP periods can be used by practitioners to adequately prepare athletes for periods of high intensity activity [9,10,11,12, 16]. In this regard, representative training may be designed and monitored in order to meet the maximum intensities, or a desired percentage of the maximum intensity, recorded during AF matches . For example, a training drill for a key position player at 100% of maximum BiP intensity should be performed at around 219 m·min−1, which can be ensured in real time with the use of live-feed GPS technology. This approach ensures that athletes are adequately prepared for the most physically demanding periods of match play, which may not be achieved if training intensities are derived using a whole game approach . Similarly, end-stage rehabilitation drills may also be designed and monitored utilising the same approach, ensuring that athletes are exposed to likely maximal match running intensities before returning to competition, thus increasing their levels of preparedness [16, 30]. Furthermore, it is hypothesised that gaining real-time feedback of the running intensities during BiP periods in competitive matches, through the use of live-feed technology, may have utility in informing interchange-rotation strategies. However, further development and research is required in this space.
Previous research indicates that positional differences exist in physical output during AF matches , this was not evident when studying the maximum BiP periods. This suggests that all players are exposed to similar maximum bouts of high-intensity activity of ≥ 30 s in duration. Therefore, it may be beneficial to develop players within a training environment who are adaptable to playing within multiple positions, thus exposing them to a multitude of potential scenarios and problems, which may have a benefit to both player development and the tactical flexibility afforded to AF coaches. Previous research identifying maximal periods of play using rolling time frame methods has shown conflicting evidence regarding positional differences, with Johnston and colleagues  finding no effect of playing position, whereas Delaney and colleagues  were able to demonstrate differences based upon playing position. Several reasons may be hypothesised for the finding within this study. Most likely, the increased “fluidity” placed upon AF players to play multiple positions within one game, which is particularly evident with the team used in this study. Additionally, differences may have been recognised had the subjects been delineated into smaller positional groups. However, due to sample sizes, this would have required the collection of data across multiple seasons and possibly multiple teams.
When maximum BiP periods and averaged data were compared on a quarter-by-quarter basis, significant differences were still demonstrated (Table 3). This increases the validity of the BiP method when identifying high-intensity periods of play, and thus increases its practical application. Additionally, this finding highlights that athletes are often required to perform periods of high-intensity activity, that are substantially higher than those demonstrated using averaged data, throughout the entirety of a match. Although it had been expected that the magnitude of difference would decrease from the 1st quarter to the 4th, the ratio of difference remained relative stable across the 4 quarters. This may imply that accumulated match fatigue effects a player’s ability to perform all activity, including intermittent bursts of high-intensity activity, to the same degree.
The maximum BiP period from each game were contextualised with technical actions, such as kicks and handballs (Table 4). There was a greater demand on athletes to perform a technical action when the BiP period was defined using higher velocity bands (e.g., very high-speed running). This suggests a player’s ability to produce high velocity outputs may be important to match involvement, and that developing this component of fitness is of importance amongst AF players. This finding could potentially be explained by the work of Sheehan et al. , who suggest that links to high velocity movements may be explained by the requirement of players to “beat” their opponents to the ball, or to create space in order to receive the ball from a teammate. This may have important implications for training, where there appears to be a need to create environments where skill execution is performed under match conditions (e.g., speed, execution time, physical pressure) in order to enhance positive transfer [14, 28, 31]. However, it should be noted that previous research has demonstrated that during peak periods of play, average speed was reduced as the number of technical involvements increased . Although this present study demonstrated that more involvements occur in BiP periods defined using higher velocity bands, a cause-and-effect relationship was not established. Therefore, an element of caution should be exercised with this finding.
Additionally, BiP periods defined using acceleration efforts and PlayerLoad™ involved the greatest number of technical involvements, particularly amongst the key position and mid-wing playing groups. As explained by Johnston and colleagues , players are often required to perform technical actions within confined spaces, where acceleration load is likely increased, which may go some way to explaining this finding. As PlayerLoad™ is a measure of all accelerations across three movement axis (X = mediolateral; Y = anterior–posterior; Z = vertical) , it may be hypothesised that movements such as turning and changing direction are also important to performing a technical involvement. However, further research is required to establish this relationship. Alternatively, the game context may be the greatest factor in the opportunity to perform a technical action. As the majority of BiP periods begin with an umpire re-start (i.e., centre bounce or throw in), players are located within close proximity to the ball, thus increasing their likelihood to perform a technical action.
Some positional differences were noted in respect to technical involvements. With few exceptions, the mid-wing group experienced the greatest technical demand. This is somewhat to be expected when they are often positioned close to the play and their role requires them to “follow” the ball [1, 9, 10]. However, it is maybe surprising that key position players performed more technical actions than the half-line players, especially when they are often confined to smaller areas of the oval . This may be attributable to hit-outs which are only performed by key position players, however, evidence also suggests that they often perform a greater number of marks, kicks and handballs during maximum BiP periods. Due to their position on the field (i.e., near the attacking or defensive goal), these actions may be critical to match outcomes, where they may contribute to a goal being scored or prevented . Additionally, it should also be noted that half-line players may also perform more off the ball actions (e.g., movements that draw defenders to allow greater space for teammates to receive the ball ), in order to gain a tactical advantage for the team. Although these do not collect a statistic, these movements are often desirable and may contribute to team success.
These findings regarding technical actions demonstrate the need to integrate both physical and technical development in a combined approach to training. Our findings demonstrate that athletes performed an action in 21% to 48% of maximum BiP phases, suggesting that an action should be included in any representative training drill aimed at replicating these periods of play. As previously mentioned, there is a need to create training environments where athletes are not only exposed to maximal intensities (e.g., meterage per minute), but also to those which require the execution of skill at match pace [14, 28, 31]. This is supported within the current literature which demonstrates that kicking effectiveness is influenced by both time in possession and the level of opposition pressure . Additionally, Ireland et al.  demonstrated a disparity in pressure on both the player in possession and the receiver, as well as kick execution time, in current AF training practices compared to competitive matches. Therefore, it is hypothesised that representative training centred around maximal periods of play may go some way to improving current practice design.