Total Running Distances
Data presented in this review highlights that, when playing positions are pooled, elite level male players cover approximately two times greater total running distance than their female counterparts [20,21,22,23,24,25,26,27,28]. This may, for the most part, be attributed to the differences in on-field playing time experienced by these athletes, with some female players competing for around 54 ± 10 min, whereas male athletes spend around 101 ± 12 min on ground [1, 28]. A similar trend was observed when assessing running distances with players delineated into the various playing positions, where male players covered greater distances than female players.
Interestingly, when distances are reported relative to playing time, differences are somewhat diminished. For example, Coutts et al.  reported male midfielders to cover more than double absolute running distances (12819 m, 95% CI 12,603–13034 m) than those highlighted within female midfielders (5813 m, 90% CI 5120–6505 m) in the report by Clarke et al. . However, when expressed relative to playing time, there were no differences between the results (males; 128 m·min−1, 95% CI 126–130 m·min−1, females; 128.4 m·min−1, 90% CI 121.5–135.3 m·min−1) [4, 38]. The same results were also evident when making comparisons across the other playing positions highlighted within these two manuscripts [4, 38]. This finding not only demonstrates the potential comparative nature of male and female competitions, but also highlights the use of relative distances as a potentially more viable method when making comparisons across the two playing levels.
Additionally, it is valuable to compare those competing at different playing levels (e.g., elite vs sub-elite) as often those at the sub-elite level are drafted to the elite level competition, particularly within female AF. These comparisons can also inform physical performance pathways so that development players can be adequately prepared for elite level competition. Data presented within this review highlights that absolute total running distances performed within male AF matches is reflective of playing standard when playing positions are pooled together, with elite level players recording greater distances than sub-elite athletes [20,21,22,23,24,25,26,27]. However, when data for male elite and sub-elite athletes are delineated into playing positions, the differences between playing levels are not so clear. For example, Kelly et al.  found no significant differences between male elite and sub-elite nomadic and rotating position players (13,193.14 vs 13,189.34 m respectively). This was also evident when running distances were expressed relative to playing time where, in some cases, sub-elite level male athletes recorded higher meterage per minute than elite level athletes [23, 33, 34].
Amongst female players, there were contrasting results when comparing between playing levels [3, 38, 40, 41]. For example, of the six playing positions explored within the study by Clarke et al. , only female elite level midfielders and small forwards out-performed their sub-elite counterparts, potentially owing to the differences in playing time (elite 49 min, sub-elite 60 min). However, when these data were presented relative to playing time, there was a trend for an increase in running performance amongst the female elite level playing groups . With these results in mind, it is possible that males performing at the sub-elite level are better prepared to perform at the intensity levels required at the elite level than females. Additionally, previous research has highlighted that the duration of sub-elite male AF matches is approximately 7 min longer than elite matches, potentially aiding development of match related running performance in sub-elite players . However, it should be noted that Johnston et al.  reported elite level male players demonstrate superior performance in several measures of physical capacity to their sub-elite counterparts, inclusive of 3 km time trial, yo-yo intermittent recovery test, 20 m sprint and vertical jump, which should be considered when assessing the preparedness of sub-elite players to perform at the elite level. Additionally, it should also be noted that very few data exist at the male sub-elite level where players are delineated into discrete playing positions, which weakens our ability to make judgements of this nature.
Finally, it is common amongst male competitors for midfielders, nomadics, and small position players to cover greater distances (both relative and absolute) than tall and key position athletes [4, 5, 30, 35,36,37]. Johnston et al.  note that this is likely due to the requirement of midfielders and small position players to somewhat follow the ball, therefore utilising more of the playing oval, as opposed to tall and key position players whose role confines them to smaller sections of the ground. However, this trend was not always replicated within female populations, where there were some examples of tall and key position players out performing the midfield and small position players [3, 28, 38]. This finding may be attributed to sample size and player on-field time, which varies between the positions reported in the aforementioned studies [3, 28, 38]
These findings can enable practitioners to plan appropriate training volumes and intensities. Oftentimes, training load and intensity is prescribed based upon the physical requirements of the game and the position the player occupies. In this instance, the findings of this review suggest male players require higher running loads in order to adequately prepare for competition [20,21,22,23,24,25,26,27,28]. However, although female players seemingly require less overall volume of running based training (due to the reduced distances travelled in matches), the exposure to similar running intensities (i.e., relative distances) as their male counterparts appears desirable [4, 38]. This may be particularly relevant amongst sub-elite female players, where practitioners may wish to improve relative running performance/ running intensity in order to prepare female players for potential draft to the elite competition .
Running Distances Performed in Discrete Velocity Bands
Due to the vast array of speeds used to define different velocity bands in the literature, cross-study comparisons were particularly challenging. However, what remains consistent across this body of research is that as velocity increases above high-speed or high-intensity running, the distance travelled decreases across all playing levels, and for both sexes, demonstrating the challenges faced by AF athletes in maintaining high-speed running outputs.
When studying high-intensity or high-speed running, distances covered at > 14.4 km·h−1 (> 4 m·s−1) were reported for elite male and female athletes [4, 21, 22, 28, 38], indicating that male athletes record greater distances above 14.4 km·h−1 (> 4 m·s−1) than female athletes across all positional groups, with elite male midfielders covering markedly greater distances (4314 m, 95% CI 4166–4462 m)  than elite female midfielders (1252 m, 90% CI 995–1508 m) . These differences may be attributed to the increased ability of males to attain higher running velocities [28, 30], the differences in the style of play between the male and female game , and to the shorter game time in the female competition. However, when playing time is taken into consideration, Weston et al.  reported relative high-speed running distances to be 36 m amongst elite males, with the highest recorded for elite females seen amongst the midfield group as 28 m .
Additionally, an approximate 5–10% increase amongst male players was noted when calculating high-speed running as a percentage of total running volume. When all positions are pooled male athletes perform 26–33% of total running distances at a velocity > 14.4 km.h−1 (> 4 m.s−1), with females completing 22% at high speed [21, 22, 26, 28]. When athletes were delineated into their various playing positions, male midfielders and small or mobile position players performed around 8% more high-speed running relative to total distance than female midfielders and small/ mobile position players [4, 28, 38]. However, male and female tall and ruck position players performed much similar percentages at high-speed [4, 28, 38], further supporting the notion that positional role may play a significant role in the opportunity for these positional groups to perform high speed running .
As previously mentioned, the differences in the completion of high-speed running during AF matches may be explained by several factors. These include both the increased playing time experienced by male players and the more “open” style of play evident in the AFL, which lends itself to high-speed running, as opposed to the contested/ congested play evident within the AFLW . Despite these limiting factors within the female game, the ability of male athletes to complete more high-speed running, given the same velocity threshold, is likely attributed to their ability to attain greater maximal running velocities during match play [28, 30]. Previous research in similar sports has demonstrated male athletes display superior physical qualities, inclusive of countermovement jump height, sprint speed and performance upon the yo-yo intermittent recovery test, potentially aiding their ability to repeatedly produce greater maximal velocity efforts . Therefore, when the same speed is utilised to define high-speed running zones, it is likely that females will experience a higher physiological cost than their male counterparts .
As it has also been established that sprint performance is strongly associated with strength qualities, and therefore training status, the ability of female AF players to attain greater maximal velocities, and potentially increase their capacity to both complete and tolerate high-speed running distances, may be improved with greater exposure to training of this nature [50, 51]. This is particularly pertinent with elite female players who are reported to have a younger training age relative to their male counterparts, whilst also having reduced opportunity for training due to the part-time nature of the female game . This is an important consideration, as greater pre-season training load (e.g., total and high-speed distances) has been associated with an increase in running performance during AF matches amongst male populations . Furthermore, maximal aerobic running speed , 2-km time trial and yo-yo test performance , as well as measures of lower body power , have all been associated with running performance of male players. Therefore, in order to further enhance the female game, and to develop appropriate physical development pathways, it is a necessity that female athletes are afforded a greater opportunity to train.
Due to the reduced ability of female players to reach similar maximal velocities, a more accurate comparison may be made if high-speed running is defined utilising a percentage of maximal speed or similar physiological measurement. This method has been employed in female rugby sevens, where it was shown that a globally applied zone can under estimate high-speed running compared to one applied through the use of a physiological measure . However, it should be recognised that applying a physiologically based threshold is not without its own complications, and requires further consideration . It should also be noted that 14.4 km·h−1 (4 m·s−1) does appear to be reasonably slow to utilise as a measure of high-speed running, especially when it can be considered to be less than 50% of a male athlete's maximal velocity .
PlayerLoad™ was reported for male and female athletes across varying playing levels. Amongst male athletes, those at the elite level recorded higher values than their sub-elite counterparts [21,22,23]. The research by Clarke et al.  highlighted that female athletes recorded lower PlayerLoad™ volumes than male athletes, likely owing to the reduced playing time experienced by female players, and additionally, that midfielders and small position players perform a greater volume than tall position players. This was also noted within male populations, where Boyd et al.  reported midfielders and nomadics to record higher PlayerLoad™.min−1 than both ruckman and deep position players. PlayerLoad™ has been positively related to running distances, in part due to foot strike impacts contributing to the total load [25, 43]. Therefore, these findings are perhaps unsurprising, with male athletes and small position players having previously been shown within this review to cover greater running distances than female athletes and tall position players respectively. However, it is important to note that recent research has demonstrated PlayerLoad™ may underestimate actual player load by ~ 15%, highlighting the need for caution when utilising this metric in both research and practical settings 
Previous research has demonstrated that using averaged data (e.g., total distance divided by total game time) can underestimate demands of intermittent type team sports [31, 39, 48, 55,56,57]. There has been a growing trend to identify the peak, or the most intense, periods of play within recent research [28, 31, 39, 47, 48, 55,56,57]. These periods have been established within AF, typically using a rolling-time frame approach [31, 39, 47, 48]. Peak periods of play could be seen to be as high as 1.8 times greater for meters per minute, and over 4 times greater for high-speed running per minute, than that recorded using whole game averaged data amongst female AF athletes . Similarly, Johnston et al.  demonstrated within male populations that both meters and PlayerLoad™ per minute could rise to almost twice those seen using whole game averaged data during peak periods of play. In comparison, Thornton et al.  found that the peak 1 min period, recorded amongst elite female athletes, was reasonably similar to that recorded within male populations [31, 48]. However, the decline in physical output during 10 min periods was seen to be greater within female players, indicating that female athletes are not as able to maintain high intensity outputs over longer time periods . Additionally, the peak period intensities highlighted by Thornton et al.  appear to be substantially higher than those found amongst sub-elite female athletes , highlighting a potential area for development amongst this population.
Delaney et al.  reported that, amongst male players, the highest demands during peak plays could be seen amongst the mobile forwards playing group. The review by Johnston et al.  speculated that, due to the playing position, these highly intense periods of play may be occurring during critical game moments (e.g., creating goal scoring opportunities). Although the contribution of high intensity actions to successful play has been somewhat established within soccer  and rugby union , to the knowledge of the authors this is yet to be established within AF populations, and therefore warrants further research. Furthermore, it was generally established within the included literature that the shorter the time frame analysed, the greater the demands were found, suggesting that stint duration has an effect upon the values recorded during peak periods for both sexes [31, 39, 47, 48]. It is important for both sports scientists and coaches to have an understanding of the demands of these shorter epochs and how to best prepare their athletes for these events [48, 60].
Match quarters [3, 5, 45, 46, 61] have also been investigated within AF populations. Decrements in running performance, for both males and females, were noted across quarters, with the greatest differences noted between quarter 1 and quarter 4, presumably indicating the increased impact of accumulated fatigue [3, 5, 45, 61]. Interestingly, Mooney et al.  demonstrated a very small, non-significant, increase in distance and high-speed running distance in quarter 3 in comparison to quarter 2 within a population of male players, possibly highlighting an effect of the half time break. It appears that within female AF populations, this decrement in running performance is accentuated at the higher velocity bands (e.g., sprint speed running), again highlighting the challenge facing AF athletes when attempting to maintain high-velocity outputs . Finally, coaches can expect running outputs to be higher during quarters lost than quarters won [5, 46].