Footy is often said to be a game for all shapes and sizes. The nature of the game, with the ball often both in the air and on the ground, provides opportunities for both tall and small players.

Success stories such as 168cm Caleb Daniel, 167cm Brent Harvey and 163cm Tony Liberatore are used to demonstrate the success that small players can have in the AFL. Often overlooked, however, is that players like these have had league-best traits to helping them overcome their lack of height. Daniel’s 90% kicking efficiency at the U/18 championships combined with the equal-second highest beep test of all time at the draft combine testing is not mentioned as often as his height. Brent Harvey was not only durable enough to break the games record, he was also, arguably, the league’s best kick inside 50 at his peak. Tony Liberatore also can be considered the greatest tackler of the modern era.

This line of thinking overlooks inability for talented, but short, junior players to transition to AFL level. 170cm Fortunato Caruso and 174cm Ben Cavarra were Morrish Medallists who were overlooked in the draft due to their height and 172cm Andrew Hooper was also decorated at junior level and could only manage seven AFL games.

Understanding the fact that height effectively is normally distributed (also known as the ‘bell curve’) in populations, means that, by extension, there is a greater “depth” of skills unrelated to height around human-average height than there are players that are significantly taller, by simple sheer weight of numbers.

However, despite this, it is evident the nature of football is that the best players, elite at AFL level, are advantaged by their height. Ben Cavarra, is less than 2cm shorter than the average Australian male. Despite showing certain other traits, that were arguably the strongest of any player out of the thousands that were eligible to be drafted that year, he was not one of the 130-odd players drafted.

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This graph shows of an estimated distribution of all weekly club AFL players, representing the talent pool of players that could theoretically be recruited to play in the AFL, the height of all AFL listed players, and the height of all AFL listed players excluding both the American college convert recruits (who have been recruited from outside the Australian talent system) and those who have not yet played an AFL game.

The median height of AFL players stands at 188cm, with right-skewedness of the distribution (more very tall players than there are very short ones) meaning that the average height is closer to 189cm.  This is significantly taller than all weekly players of football, which is in turn taller than the general population at large.

How does height influence footy? The answers may be obvious but I’ll list what I believe are the most significant (thanks to our good friend Wikipedia). Greater height creates greater reach above the head (as the game features overhead marking) and greater absolute strength (as it’s a contact and physical sport). Being short can also help in terms of centre of gravity and agility, however given the distribution these advantages are clearly washed over by the advantages found with greater height.

Looking at other sport’s height’s distribution can also be an interesting exercise. Soccer has a height distribution similar, though slightly taller, than the general population at large, where whilst the ball is often aerial, a lower centre of gravity significantly helps dribbling. Basketball naturally lends itself to a staggeringly high height distribution, whilst the recent prioritisation of wingspan over height also noteworthy. Tennis players are similar in height to footy players, where height helps serving but inhibits returning. Tennis also interesting for gender comparisons – being tall relative to the wider population seems to be more advantageous for females than it does males. We’ll get to gender comparisons for footy a bit later.

Unlike soccer, the benefits of agility and lower centre of gravity in shortness for footy are marginal at best. Instead, the major skills of the game, like kicking and handballing are negligibly related to height, and their typical association with shorter players are simply a feature of a greater amount of football players around the human average height, and therefore, the best in the league in these areas are more likely to be found in a shorter player. Theoretically, 86 of Australia’s best 100 kicks should be shorter than about 186cm tall (within one standard deviation of all active player’s heights), but that clearly isn’t the case at AFL level, demonstrating the significance of height and being an effective AFL player.

A lot of the discourse around drafting shorter players, or typical skills and other forms of athletic capabilities, as a result are scientifically incorrect. For example, shorter players in the AFL would be better skilled and quicker than taller players, but that’s a representation of the greater depth in talent around population-average height – scientifically speaking, taller people are faster. The national talent manager Kevin Sheahan stated in 2009 that “The introduction of the [kicking test at the draft combine] would send a message to prospective players, that getting their skills spot on would open doors, no matter what size they were” and that “kicking skills are essential and that, if you can kick, you’ve got a chance”. Given that 168cm Caleb Daniel, a 90% efficient kicker at the U/18 national championships, was drafted at late as the third round only on the back of his equal-second-highest-in-history beep test, that seems like a long bow to draw.

Discourse that the collective wisdom of AFL list management is incorrect overlooking shorter players is also puzzling. For every Tony Liberatore, there’s a significantly greater number of Fortunato Carusos, a player who has only carved out a solid local footy career.

Perhaps cognitive biases can be the answer, of which recruiters are more equipped to overcome. It’s easy for a pundit to over-rate the impact of skills developed through effort, hard work and training, like kicking skill, and under-value the impact of natural athleticism, like height, because the player didn’t have to “work” for them. No doubt these cognitive biases exist in recruiters, but that’ll be less the case than the average pundit or someone involved in lower levels of football where an incentivisation of hard work is different to a professional competition attempting to win games than it is for AFL level.  Every AFL team would recruit LeBron James if he wanted to be a convert athlete even if he refused to train, yet local football teams might have different selection policies by nature of not being a professional organisation.  The same principle remains for those surprised that a great character, hardworking shorter player might be overlooked by a lazy athletic player who didn’t hadn’t had to work for their natural athleticism.

The good thing about understanding height and how it influences player ability is that it’s absolute, and it’s something that we can compare the relative importance of height as a fact of what makes an effective player. It’s the one skillset that we can compare every player to definitively and easily through the data of player height in centimetres. That lends itself to greater understanding of the talent pool at large and how different skills athletic traits are valued within a talent pool.

Take kicking distance. Any footy player who struggles to kick 40m would almost certainly not be drafted, irrespective of their other athletic traits and skills, much in the same way that any player shorter than 170cm would not be drafted. Matt Priddis is one of those rare players who has forged a very successful AFL player with the ability to only kick a short distance. The success of Matt Priddis isn’t really resulting in many others saying that “players who don’t kick that far” are undervalued in the same way as height. A comparison can be made with Tony Liberatore, another Brownlow Medallist who was only 163cm tall and also recruited as a mature-ager. Liberatore’s success has many stating how shorter players, at large, are undervalued. Priddis’ success hasn’t meant that there’s been discourse, at large, of the undervaluation of short-kicking players.

As height is absolute, consistently and easily measured from player to player, is easily accessed through online datasets or tables and is comparative, there’s the argument that’s the most accurate and effective skillset or athletic trait that we can measure in understanding any of the various factors that AFL teams look for when recruiting players.

We can compare the difference of height at the highest and lowest levels of football and determine the definitive importance of height as a skillset for AFL success more than anything else. For example, we know a longer kicking distance also helps a player’s effectiveness at AFL level, similarly to height, but what is the ‘typical’ kicking distance for a suburban player, what is the mathematical difference in kicking distance between those players and those in the AFL, and therefore the difference between the elite and local level, relative to height? It’s effectively impossible to know. Height is the only trait that we can do this sort of analysis for.

Commentary of kicking distance was also prominent in the first AFLW season. Many made observations of the lesser kicking distance found in the AFLW, and somehow placed that as an indictment on women’s footy in general. Given the above, it’s clear, however, this reflects the talent pool as a whole, which is smaller and lower quality for female football given lesser grassroots and youth development on top of simply smaller player numbers, as opposed the genetic capabilities for females to kick less than males.

I’m unable to find any scientific research of how far females “should” kick a footy, relative to males biomechanically, and in any case, the introduction of a smaller size 4 football for females instead of the older size 4.5 (with male football using size 5) would make any old research moot with the size 4 footy being able to be kicked further. If 90% is a good scientific rule of thumb, in theory, at the elite level, in much the same way that the range of almost all 45-55m for the male AFL players, the range of AFLW player’s kicking distance should be 40-45m.

Whilst we can see it with certain players who kicked the ball 45m or further, that clearly isn’t true for the depth of the 220-odd AFLW players. It’s because of a combination of historical lower quality junior development which would help kicking distance, and more significantly, the smaller talent pool in general.

In 2016, there were only 65 Victorian female adult club teams – in contrast to a number much closer to a thousand for male football. The four Victorian AFLW teams were effectively picking one in twenty active footy players for their AFL squads – my guesstimate is for male footy, the AFL would be selecting at the bare minimum one in one thousand active adult players. Male players whose inability to kick a long distance preventing them from an AFL career would not be true for the AFLW, where the lower number of total players to pick from naturally results in those with flaws in their game (even as obvious as lack of experience through being recruited from other sports) not being overlooked.

The same theory that applies to kicking distance should also apply to height. The beauty of height data is that it’s not something we have to theorise – as explained above, we can look at it with absolute, consistent data. If the theorising is correct above, the height, relative to the talent pool at large, for elite female footballers should be shorter than male players. Guess what – it’s true!

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Standardising the distributions for both men’s and women’s footy and placing it on the same graph allows for greater comparison:hglmxxi
Elite female football is indeed shorter than male football.

Another factor is the appeal for different sports, especially netball and basketball, for taller athletes, where professional competitions have been running for decades and international competition is an attractive point.

The AFL will, with expansion in the coming years, overtake these two leagues in gross player payments. Whilst average payments are currently lower, there are hundreds of more list spots available in the AFL than those sports. Basketball and Netball has had head starts in those desiring to become paid athletes – something that we envisage will adjust over time, both with convert and junior athletes, contributing to elite female footy being taller and taller over time.

It’s easy to speculate the different nature of female footy – scrappier with the ball aerial less often – as another explaining factor for the difference in height. I would suggest that’s not really the case, as the game was still structurally set up the same way – the proportion of key position and ruck players in the AFLW was effectively the same as the AFL. The greater contested nature of the game also makes absolute strength, found in taller players, more important.

As such, we can use height to effectively understand the gulf of talent pool and development between male and female footy. Using analysis of height allows us not only to understand that elite football is fundamentally a domain of tall athletes in contradiction to many who say it’s a game for all sizes, but also allows us to compare how much the two different genders of football capture the athletic talent pool at large. It certainly is a tall order.

Notes

The “talent pool” for male and female players is taken from the general population per ABS data, though, the standard deviation is slightly higher, and there are adjustments for middle-aged shrinkage.

With 45 list spots and hardly any team ever using more than 35-40 players per season, the final list spots with later draft picks in the AFL are typically used for “development” purposes as opposed to depth, with higher-variance players whose future success is harder to predict. As such players who have not yet played an AFL game tend to be taller draft picks as taller player’s future success is harder to predict at age 18 than other positions. If list sizes were reduced, the league would almost certainly be shorter.  On this graph, the height of the “talent pool” is about 3-4cm taller than the population at large with self-selection bias (active players are more likely to be taller as they’re more likely to stick with the game as adults, given they’re simply the better players)

Data for elite female players is  taken from VFLW listed players, where the height data was easier to access and filter. Over half of AFLW listed players are in this dataset, and I believe the sample size advantages of a much larger number of players outweigh the possible negligible difference in height distribution between AFLW and VFLW level. The self-selection bias adjustment is also reduced for women’s footy – the incentive for shorter players to begin, and shorter players to not drop out of weekly footy in general, I believe, are less for men’s footy than it is for women’s footy. If this second assumption wasn’t applied, the difference in height distribution between the two genders would be even greater.

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