‘ Making the BALL TALK Inside features
Each of the players who had been involved in the use of performance enhancing drugs would be liable for prosecution for an anti-doping rule violation. – Former head of ASADA Richard Ings on The Morning Glory
Ball-tracking technology will add a revolutionary dimension to game analysis, writes DR JODI RICHARDSON.
HE AFL is considering trialling new ball tracking technology in the NAB Cup that would give clubs unprecedented match analysis information. GPS technology has allowed tracking of player movements for years, yet never before has the movement of a ball been tracked in the way we hope to see in the coming weeks. Once approved for implementation, this new technology will again put the AFL at the cutting edge on the world stage of sports science. What’s impressive is that this will be achieved by the addition of a single device, weighing just a tad more than a 50-cent piece, to the match ball. Engineers and sports scientists from Catapult Sports, a Melbourne company, have spent years developing their SmartBall technology. The tracking system works by the securing of a 17g module (a transmitter of sorts) inside the bladders of Sherrin “SmartBalls” before the manufacturing stage. Catapult’s media and marketing manager, Boden Westover, explains that it has been a time-consuming process to get this critical part of the system right. “We’ve been working very closely with Sherrin, sending the modules their way and having them stitched into the balls,” Westover said. “There’s the consideration that the balls take a beating over the course of a game.” Once the module is fixed to the inside of the bladder, the leather casing of the Sherrin is secured around it to complete production. The SmartBalls are branded with “Catapult SmartBall” to differentiate them from other Sherrin footballs. Westover said that the device was secured inside the bladder underneath where the ball was pumped up with some leeway to allow for the high forces on the ball with kicking. It’s no wonder this stage of development required trial and error as even though the time of foot contact with the ball is short, around 1/100th of a second, the force measured during that impact can be as much as 100kg. The fixing of the device as well as the electronics must be extremely robust to withstand that type of repetitive force during a game. A clever aspect of this technology is that the module inside the Sherrin does not need to include a GPS receiver for the movement of the ball to be electronically tracked.
‘Our systems will be able to tell you the story behind the possession.’ The module inside the ball is tracked by Catapult minimax GPS units worn by players. This is why Catapult has been able to reduce the weight of the SmartBall module to only 17g. This ensures that weight of the Sherrin is not pushed over the 520g upper limit. Further to the care taken to maintain regulation ball weight, the flight path of the SmartBall has been tested by scientists at the University of South Australia and Victoria University to ensure that it remains unaffected. The movement of the ball is tracked as the device inside the ball is detected by nearby minimax GPS devices. Catapult already supplies these units to 17 AFL clubs (Geelong is the exception). Since minimax accurately tracks each player, and the ball is near the players nearly all the time, Catapult’s revolutionary system can compute the position of the ball – and differentiate between who has possession and who is near the ball or contesting possession. The device can register a moving player who is within 85cm and updates five times each second. Determining the direction of the ball without actually tracking the ball required the brains behind the SmartBall to use advanced mathematics to produce the data clubs need, based on what is recorded by the minimax GPS systems worn by players. The use of the SmartBall in selected NAB Cup games will give clubs a first
look at how it can improve their matchday and post-match analysis, and will give Catapult an opportunity to trial its world-first technology. There are so many advantages for clubs using the SmartBall it’s hard to know where to start. The program gives a coach a bird’s eye view of the ground on an iPad screen. Players are represented by their jumper number in a circle and the circles move as players move. The program also colours the path travelled by players. These images, known as hot spot plots, show where a player spent most time on the field. One key aspect of this wireless technology is that match analysis data is streamed to the coaches in real time, meaning without delay. Coaches can see who is in possession of the footy, number of possessions for each player, the time a player is in possession of the ball, the distance a player travels to get the ball, the distance of a player’s last possession, the distance of all possessions for each player, a player’s velocity at possession, their velocity at disposal, and pass chains between teammates. Westover explains that besides the opportunity for immediate and greater tactical analysis, the SmartBall offers a huge advantage when it comes to video analysis. “A lot of the teams rely on (the broadcaster’s) video for match analysis, yet because the field is so big and there are so many players, a lot gets missed or Inside Football
it gets distorted with the view,” he said. “The SmartBall data gives coaches a 2D view of the game, bringing their whiteboard to life. This simplifies the learning process when they are talking about strategies and structures. “From a training point of view, right now most teams video their training and have someone standing on the side to count possessions and diagram player movements. There is no technology that can record that kind of movement in training. “Clubs can get GPS data which describes how far and how fast players are running but there is nothing to calculate how effective they are in training. A player might look like he’s had a great training session, running long distances all over the field, but then when you look at the stats he could have had two kicks in one hour.” Catapult’s business developer, Paul Dear, played for the Hawks for 10 years and his AFL experience gives him a first-hand understanding of the potential of SmartBall. “At the moment, review of the game from a tactical point of view is all video based,” Dear said. “It’s all subjective based on the person doing the review. It’s extremely time consuming and labour intensive. “With the Catapult system, all data is logged in real time and is available immediately. A coach could use the data by adding a graphic overlay of a strategy for a kick-in for example, and then ‘scroll’ through the game to see if the team achieved that structure or not.” Currently, Champion Data provides statistics on possession strings, among many other things, but the SmartBall data gives another layer of information. “Clubs will have all of their statistics
Wednesday, February 13, 2013
on kicks and handballs and our system will add to that information about ball movement, and player movement in relation to the ball,” Dear explained. “They are quite separate areas.” “What our systems will be able to tell you is the story behind the possession. Where do the players come through, what was the starting structure, who provided the block? “Who held the space for the player to be able to lead into? Or vice versa, who was the backman that filled the space to force a kick wide? “We’re not looking to replace the statistics of the game as our technology has to interpret some aspects of the information. “Because the ball is tracked in relation to the minimax units on players, if the ball moves from one player to another 40 metres away, in most cases our system would interpret that as a kick, even though the system gives a different output for kicks and handballs. “There will be a lot of trial and error in that process. “Ultimately, we will be looking at the loads associated with kicking the ball. Kicking is a very physical process and is one area where sports scientists would love to get statistics in terms of load in relation to injury.” Catapult is talking to a range of organisations about the best use of the technology and the best avenues for clubs, supporters and the AFL to get access to the data. It even has entertainment potential for broadcasters. Access to the 2D animations of player movement would enable commentators to give their audiences greater insight into team strategies. “It is an exciting time and it will be great to provide different metrics about the game,” Dear said.
Published on Feb 13, 2013
The AFL are considering trialling a new ball tracking technology in the NAB cup which would give clubs unprecedented match analysis informat...