Deliberate practice in John McPhee‘s A Sense of Where You Are: Bill Bradley at Princeton

In high school:

…he obviously needed considerable practice, so he borrowed keys to the gym and set a schedule for himself that he adhered to for four full years-in the school year, three and a half hours every day after school, nine to five on Saturday, one-thirty to five on Sunday, and in the summer, about three hours a day. He put ten pounds of lead slivers in his sneakers, set up chairs as opponents and dribbled in slalom fashion around them, and wore eyeglass frames that had a piece of cardboard taped to them so that he could not see the floor, for a good dribbler never looks at the ball.

At Princeton:

When Bradley, working out alone, practices his set shots, hook shots, and jump shots, he moves systematically from one place to another around the basket, his distance from it being appropriate to the shot, and he does not permit himself to move on until he has made at least ten shots out of thirteen from each location. He applies this standard to every kind of shot, with either hand, from any distance.