On the topic of hill physics.

BearJuden

Question regarding running: I understand why, on a treadmill, setting an incline increases the calories burnt. But...does this actually work outside? Why? Because, as someone who understands phsyics and not physiology, any energy you build up going up a hill is lost going back down it. Is the difference caused by the body really all that big?

hermann341

It's the level of effort required to run up the hill. The increase in your heart rate to run up the hill from straight and will be greater than the decrease in your heart rate running down the same hill from straight and level at the same speed. The tendency though, is to run faster down the hill, and your heart rate will be about the same as straight and level.