Play on. GPS data tackles the pace of AFL games

In the AFL, midfielders have a reputation for doing the grunt work, racking up the kilometres as they chase the ball the length of the oval, while forwards get to relax and wait for their opportunity.

But new research from Edith Cowan University and Flinders University suggests that the pace at which a player runs is dependent upon the phase of play they’re in – either in attack, defence or contested – which vary between playing positions.

The data, collected by health scientists Chris Wing and Dr Nicolas Hart using GPS data from 32 male players from a West Australian Football League (WAFL) club across 19 games in the 2019 season, suggests a new way of training these elite athletes: work to ensure every player has the same level of fitness, and you’ll end up with a tactically flexible team full of players who can play multiple positions.

A second key takeaway from the data is that speed in attack is vital. The team found that the faster that players run during attacking phases of the game, the more likely they are to score.

“Basically in offence, speed kills,” Wing says.  “However, in defence, we found the more intensely you run, the less successful you are.”

While the reasons for that remain unclear, Wing has a theory – players positioned near the ball have a higher chance of stopping the opposition compared to those who are further away, who must run harder to impact the play, which they are often unable to do.

The study, published in BMC Sports Science, Medicine and Rehabilitation, took Wing, a PhD candidate at Edith Cowan, years to sift through and analyse. A keen sports fan, Wing has been coaching athletes for years both in his native UK and Australia, where he currently works as a strength and conditioning coach in Perth.

He came across the idea of using GPS to track running patterns of players in 2020, but COVID disrupted that season so much that Wing had to improvise and pull data from the 2019 season instead.

But how does GPS work when it comes to measuring the performance in footy players? “It’s sewn into a pocket at the back of the players’ jerseys, and measures the velocity (so the velocity of an object in motion at a specific point in time) and the distance the player travels during the game,” Wing explains.

Access to the data made it easier for Wing, Hart and colleagues to find out if there is a relationship between how far and fast players run and a successful defence, offence and contested play. If they understand that, sports scientists can precisely tailor a fitness program for players in different roles to try to gain an edge over the competition.

Positional play data enables coaches and staff to design elite training sessions that incorporate specific physical requirements, while also helping prioritise key statistics during player performance evaluations, Wing says.

“For example, data shows us that for our club, successful offence is always dependent on high intensity running, so we have to make sure to train at really high intensity so the players are ready for what’s going to happen,” he says.

While the results have certainly helped the team Wing works for (he says the team he studied has improved its speed in offence), he says it’s not just about the results. It’s also about the method.

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This is good news for the Australian Football League (AFL), the highest footy league in the country. While data gathered from a lesser league may not be directly useful for AFL clubs, knowing how to use the data available to each club based on their players’ performance is critical to success.  

“What we want clubs to know is that there is a way to measure this, and if you do, you’re more likely to find  a more accurate story about what your club is doing, and improve on that — and this can be different from club to club,” Wing says.

Hart adds that understanding the physical demands on players will improve their preparation techniques and help develop training drills more in tune with real game intensity. 

“This may have important implications for training, where drills aimed to improve a team’s offensive play, such as ball movement drills, should replicate the intensities from successful match performance to promote positive transfer to competition, increasing a player’s physical capacity in order to match these demands,” he says.

“Increasing a player’s physical capacity in order to match these demands may also prove beneficial, and is particularly important amongst the midfield and forward groups.”

Yet for Nick Bowden, head coach at Run Ready, a Melbourne coaching service that specialises in training young athletes determined to make it into the big league, the data doesn’t quite demonstrate a direct link between a club winning games and the speed of their forwards.

“We know from the data that the higher the speed in offence, the more effective, but can you say categorically that clubs with more of those players win more games?” her asks. “Are we saying clubs in the top five on the ladder are faster in attack?  That’s what the data doesn’t tell us — where’s the correlation between those two things?”

Bowden, who worked with players such as Giants forward Toby Greene before he entered the AFL, also points out that the data appears to focus on individuals rather than the context of the game, and doesn’t “fully explain the role that a player has in the team”.

“What the data doesn’t go into is why defensive players don’t generate the speed – maybe the role they’re being asked to play in the team doesn’t give them the freedom to utilise their speed in defence,” he says. 

But, like Wing and Hart, Bowden acknowledges that the clubs themselves will look at that data and draw conclusions about where their strengths are as a club, and how they might utilise positional players. “The GPS has now been in place universally across the clubs for over a decade, and in that time clubs have become really good at refining what data they need to extract from it,” Bowden says.

“This is more information they can take in and use when they need to”.