Sampras of leg strength
“A terrible thing in tennis is when you start losing your legs. If your legs get heavy and you lose the spring in them than your game inevitably declines. You no longer get up as high on your serve, and you don’t get that explosive step to the ball. you don’t move corner to corner effectively, or change direction that well. And when your opponent sees that, he uses it as emotional fuel, even if he’s also tired”