Editor's note: For most athletes, working out is just part of the program. Lifting weights, sprints, batting practice. They know the drill. But for the top athlete working out is more than just a routine. It's a way of life and they do just about anything to push their bodies to the next level. Sweat is regular feature in ESPN Magazine and on ESPN.com that takes a look at the players who know no limits when it comes to sweating it out.
For that extra burst when chasing down punts, Freddy Adu will try anything -- even an overgrown physics experiment.
Which is why the 16-year-old DC United star can often be found running with a belt around his waist, attached to a 150-meter nylon cord. The cable is anchored to a fixed object at the end of the field, and halfway between Adu and the anchor is a pulley held by trainer Corey Stenstrup.
It's called overspeed training, and Adu's been practicing it with Stenstrup at IMG Academies in Bradenton, Fla., for almost a year. The drill increases stride frequency, but it's also supposed to improve muscle memory. When Stenstrup pulls on Adu from the front, the trainer can force the futballer to run as much as 10% faster than he could on his own. And when Adu runs without help, the theory goes, his muscles will "remember" racing at hyperspeed so that he can come close to matching it without assistance.
The cable and pulley are also good for more conventional resistance training; running away from Stenstrup helps Adu generate extra bursts on sprints when he's not all tied up.
"I feel faster," Adu says. "And just a little bit of separation from a defender is all I need."
Especially if he wants that spot on the U.S. World Cup team.
Sweat also appears in ESPN The Magazine.