Football fans will be talking about Leicester City's Premier League title triumph in 100 years' time, but there's another reason the 2015/16 season will go down in history—one that will have a far longer-lasting impact on the game: For the first time, teams were allowed to use wearable devices during matches.
Unbeknownst to most viewers—and even some opponents—certain players wore tracking devices that recorded every metre they ran, every turn they made and how fast they accelerated. This data was processed and stored so it could be compared with previous matches and training sessions.
Day by day, week by week, coaches built a picture of their players' conditions and performances.