A Note on Running Form
I think when people try to “lean into a hill” while running, they bend from the waist. This isn’t what leaning should be, and its bad for your back. Try leaning your whole body forward, and don’t just bend at the waist.
The point of the lean is to move your center of gravity forward farther. If you hinge at the waist, you’re barely changing the center of gravity, you’re adding stress on your low back, and you’re adding unneeded stresses on hip and back muscles.