The Vuvuzela. What is it? World cup soccer fans know it well and have described it in every way possible, occasionally with words of endearment but more often with an air of disdain. The dictionary defines it as a stadium horn that is approximately 2 feet long and produces a long monotone sound. And boy does that sound pack a punch! Picture a stadium packed to the brim with excited fans playing the vuvuzela and you will begin to understand why many a fan chooses to hit the mute button on their TVs when watching this year’s FIFA World Cup. Even sports commentators cannot stop talking about it. But to be brutally honest, the reason why most of us are tuning in to watch one of the biggest recurring sporting events in the world is not to cultivate a love-hate relationship with a stadium horn. Rather we all want to egg on (and hopefully not egg splatter) our ‘Titan warrior’ sports men who are strategizing over how best to break the resolve of their opponents.
Run the tape back over the decades and what we find is that the success of a soccer team ultimately rests in its ability to suss out what the other team will and will not do and thereby tease apart their defense and belt the ball into the back of the net. Seems intuitive? It is a more difficult task than one might think. In the eyes of the experts, “there is great interest in better understanding [soccer’s] important fundaments…to increase the performance of a team during a game, and better adapt the planning of the trainings. The movement of the players on the field as a function of time is useful information that can contribute to improving the performance of the players at different positions.” (1)
Twenty eight years ago I walked with my parents into the San Mamés stadium in my birth town of Bilbao to watch England do just that against a worthy Kuwait team in the first round of the 1982 world cup in Spain. Being the spirited Brit supporter that I am, I put all my vocal energies into shouting for the English Lions. What I did not realize as a nine year-old was that behind the blazing performance of the English eleven lay hours of training by a squad that had sought to orchestrate nothing less than the perfect match. And they pulled it off.
Now scientists from the University of Malaga and Bilbao’s very own Basque University are taking full advantage of GPS technology to study the movements of soccer players in an attempt to document the tempo of team play (2). And the story they are unveiling is giving us a window seat view into what makes for a successful team. By attaching portable GPS devices onto players during the Spanish beech soccer matches of 2009, sports science researchers Julen Castellano and David Casamichana have drawn up a distribution profile of running speeds during a 12 minute course of play (2). On average players were found to cover a total distance of 1135 m (97.7 m/min) with speeds centered around 4-12.9 km/h. Compare this to the high-caliber artistic play of the Brazilians, who have clocked a staggering 118 m/min in Under-15 level competition (2).
The same GPS-based technology has also been put through its paces by the high-profile Australian sports research organization Sports Knowledge Australia (SKA) to look at the health impact of rapid acceleration and deceleration on athletes who regularly practice soccer, rugby and the Australian football (3). Professor Kevin Norton, who has spear-headed much of the work at SKA in recent years, has documented a higher prevalence of hip and knee replacements in retired players compared to non-players of the same age (3). He puts the blame for this rather troubling finding squarely on the faster pace of the modern games. With fewer stoppages and more serious collisions, the tension forces under which the body is placed over the course of normal play are greater than ever before. And this, notes Norton, is taking its toll, spurring further research using satellite technology. Twenty four satellites moving around the earth measuring the exact position of GPS devices strapped onto players’ backs is how Norton summarized the multi-component nature of the technology he and his colleagues have adopted. And the wealth of data they have amassed has brought scientific credibility to what is unarguably one of the most comprehensive studies of its kind ever conducted.
Not everyone in the sporting arena agrees that satellite-based monitoring of player movements is all it’s cracked up to be. Even non-experts can appreciate that GPS units add at least 250g of additional weight and so present an encumbrance to players, possibly even cramping their overall game-style (1). Pascual Figueroa, Neucimar Leite and Ricardo Barros from the State University of Campinas in Brazil have strengthened the voice of GPS-dissent by capitalizing on the emerging sophistication of a computer-based image processing tool called videogammetry (VG). VG solves the headaches of player crowding that often mar other ground-based analyses methods particularly during the defensive lineups and corner kicks of a soccer game. By positioning and calibrating several static cameras around a playing field, VG produces image ‘blobs’ that can be subsequently deconvoluted into individual segments (players) (1). Distances covered, trajectories, positions and acceleration rates can then be applied onto each segment in such a way that players and their coaches can examine the tactical breakdown of their game plan (1).
The jury is still out on whether satellite-based or terrestrial methods will win the day in the quest to better map sport kinematics. One exciting development that has got science journalists down under all fired up is the seemingly magical GPS-loaded ‘smart ball’ that will supplement the already comprehensive player data with crucial information on the movement of the ball itself (4). The gadget enthusiast in me is eager to see what the technology devotees will come up with next. And watching the English Lions crash out of the 2010 World Cup yesterday, I am sure many will gladly embrace any help they can get to bump up the quality of their play.
- Figueroa, P., Leite,N., and Barros, R. (2006) Tracking soccer players aiming their kinematical motion analysis Computer Vision and Image Understanding. 101, 122-35
- Castellano, J., Casamichana, D. (2010). Heart rate and motion analysis by GPS in beach soccer Journal of Sports Science and Medicine, 9 (1), 98-103
- See GPS helping with footballer’s injuries.
- Zac Milbank (2010) AFL footballs gets smarter with built-in GPS