The Anabolic Catalist

Sprinting is not max speed. 95, 98 % of your max max speed is max speed. That's all you can do and sustain. Going up hill also insures that the lengthening of the hamstring in the eccentric phase is not quite as pronounced. Ring at very high force outputs, so you're not going to get as sore. So it's actually a very safe workout in a lot of ways, and a very smart workout.