GPS and sport

SPORT is no stranger to the global positioning system (GPS). Satellite tracking has been used for more than ten years to map ski routes over rugged terrain, compare rowing stroke rates and boat speeds. It even settled the debate about which ball sport required athletes to run the greatest distance during a match (Australian football, apparently). Two Australian companies are pushing the technology even further: to identify poor training, reveal hidden injuries and finger myopic referees.

Nowadays devices no bigger than a mobile phone might contain a whole panoply of sensors: GPS receiver, gyroscope, magnetometer (an electronic compass), accelerometer and a heart-rate monitor. Carried between the shoulder blades in a pouch nicknamed the “bro” due to an eerie similarity to a woman’s sports bra, such gizmos can cost anywhere between several hundred dollars and $3,000 a pop, including software. Professional teams usually purchase one for each player.

They plot the unique movement patterns and bursts of intensity, allowing coaches to monitor whether all their wards are earning their keep. For example, football matches are won with short bursts of speed around the ball; those away from the action jog or walk. Players who can maintain possession are those who can sprint repeatedly without tiring. So training sessions are full of repetitive short high-intensity sprints. The new gizmos make it easier to identify laggards. During competitive games, meanwhile, coaches can accurately monitor signs of exhaustion in order to substitute players before opponents seize the opportunity to exploit their weariness.

The data also provide coaches with accurate indications of individual strengths and weaknesses, a daunting task in squads that often exceed 30 athletes. They are also an invaluable source of comparative analysis. For example, studies of football leagues in Brazil, Europe and Australia show that midfielders reach sprinting speed more frequently than their defensive teammates. Also, Brazilians do not run as far over the course of a match, but spend more time sprinting.

Meanwhile, Chris McLellan of Bond University, in Australia, has used GPS data to measure injuries sustained by professional rugby league players. He did this by correlating tackles and collisions against known indicators of skeletal muscle damage, like the hormone cortisol and the protein creatine kinase. Players provided blood and saliva samples before a game, and for several days afterwards. Mr McLellan found a clear correlation between concentrations of the biochemical markers and the measured impact force of each collision. The research has enabled teams to tailor recovery regimens to individual injuries. Those that embraced GPS technology have seen a reduction in soft tissue injuries, according to Damian Hawes, of Canberra-based GPSports Systems, a maker of such devices.

It is not just players who are being tracked. A company in Melbourne, Catapult Sports, offers training balls embedded with a tiny GPS receiver the size of a small coin. (The idea was unknowingly mocked by Google Australia in an April fool hoax in 2009; Catapult insists that the device had already been in the works by then—indeed, the company was understandably nervous that the jape might inadvertently scupper the device’s commercial prospects.) While it lacks its bro-mounted cousin’s fancy sensors, it does measure the distance of kicks and passing patterns. Combining this with data gleaned from players’ devices, it is possible to quantify facets of the game which do not show up on the scoreboard and have previously only been evident through painstaking video analysis, like which players are better at reading patterns in play, positioning themselves close to the action, or anticipating passes.

GPSports is pushing even further, developing an integrated alert system to send a beep to a referee’s earpiece within a quarter of a second of the ball going out of play, passing between goal posts or, in rugby, traveling forward from a pass, something forbidden by the rules of the game. Mr Hawes says the ball’s location can be determined to within 1cm, and expects to test the technology early next year. Australian Rugby League referees have applauded the news. The sport has embraced the use of video replays to provide officials with a second opinion on most aspects of the game, but not yet forward passes; an average televised match uses only 10-12 cameras, not enough to guarantee coverage of all possible passing angles. Several games have ended in controversy, where a scoring play has been deemed acceptable by a referee who failed to spot an illegal pass made in plain view of a section of the crowd.

Of course, some of sport’s most remarkable recent human errors have taken place in football, where FIFA maintains an adamant stance against any form of assistance which, it fears, would corrupt the beautiful game. England fans still cannot forgive the referee who failed to award their team a point after Frank Lampard’s shot on goal against Germany in last year’s world cup bounced off the cross bar and into the goal before spinning back out onto the field. Ironically, many professional football teams and national associations have fully integrated GPS data collection into their training. Both Catapult and GPSports recount their clients’ frustration at FIFA’s refusal to allow data collection during matches.

All of this information streams directly to a coach’s smartphone or tablet. The next step is for clubs to provide the same service to their supporters during games. This would certainly delight fans—and fantasy-league enthusiasts, too. Sports administrators who fail to embrace technology may soon be hearing more than beeping in their ears.