After hurting my knee in a downhill skiing accident, I went through two months of rehabilitation at the Sports Medicine Center. A lot of it had to do with specific weight training for the damaged knee's tendons, and some of the machines were hooked up as controllers to computers, where each exercise would be represented as a simple game.

To keep the story short, the games forced you to focus not on the number of repetitions or mass your were working with, but on the precise motion required for the exercise.