Part of training soccer players involves tracking their speed, acceleration and the distance they cover. For for managers and coaches, that's a challenge, since watching 11 at one time is difficult to do. Now a system of GPS devices can be used to accumulate this data and teach both players and coaches how to improve performance.
The system was designed by David Casamichana, of the University of the Basque Country. Players wear small GPS receives, which provide ten data points per second on their position. Combined with "workload indicators" — a series of figures that represent the physical condition of the player during moments of exertion — managers can evaluate their players. For example, a good indicator might be the total distance covered during training.
Casamichana used his system to study the Rayo Cantabria de Santander soccer team, a semi-pro third-division club. They wore the GPS devices in training sessions and friendly matches. (FIFA prohibits the use of such devices at the higher levels, because they may inhibit the players and give the other team an advantage).
The devices showed that position matters. Center backs and center forwards, for example, run the shortest distances. Midfielders run farther overall, but in the sprints (both the moments in a soccer match when the players are all moving towards the ball and the drills), players covered less distance at a time. It turns out they accelerated and decelerated more, and were working with more intensity.
There is also a difference in the way the players move when training than when in a match. While it might seem intuitive that a match would be more intense, Casamichana's work quantifies where that happens. During matches, players run farther, sprint longer and do so more often.
Ultimately the data will help coaches design better training regimens, geared to a player's skills and aptitudes.