International scouting recently drew an NFL general manager to Melbourne, Australia, for a few days of rugby. During a lull in the action one evening, his eyes drifted to the sideline. The head coach was walking to the end of the bench, where a team employee sat holding a laptop computer. The two conferred for a moment before the coach returned to his post and ordered a series of player substitutions.
The next morning, the telephone rang in the Arizona offices of Catapult Sports, one of several Australian-based companies that compile live data on athletic exertion. The general manager was brimming with questions for Gary McCoy, the company’s senior sports scientist.
“He wanted to know,” McCoy said, “what the hell had just happened.”