I may be missing something, but it’s not obvious to me from a physics perspective that running up hills is less impact-on-the-joints per effort, though from experience I agree it’s true. Maybe I don’t understand how impact is measured.
As long as your mass is rising at a constant rate, ascending vs. descending doesn’t change the downward force your feet must exert. Yeah, there will always be some vertical acceleration, like when cresting a hill, but unless one is running staircases with landings every 10 steps this wouldn’t be representative of the workout.
Inexperienced musing about other possible explanations:
Is it simply that effort-per-step goes up, so that fewer steps are required to achieve your goal? OTOH I’ve also been told that one should take faster, shorter steps while ascending, which would somewhat counter this effect. OTOOH maybe a short step is better on the joints than a long step. Then opting for steps that are both short and effortful could reduce a workout’s total joint-impact.
Oh, and obviously you (and your legs?) don’t move as fast. Maybe that is another contributing factor.
I may be missing something, but it’s not obvious to me from a physics perspective that running up hills is less impact-on-the-joints per effort, though from experience I agree it’s true. Maybe I don’t understand how impact is measured.
As long as your mass is rising at a constant rate, ascending vs. descending doesn’t change the downward force your feet must exert. Yeah, there will always be some vertical acceleration, like when cresting a hill, but unless one is running staircases with landings every 10 steps this wouldn’t be representative of the workout.
Inexperienced musing about other possible explanations:
Is it simply that effort-per-step goes up, so that fewer steps are required to achieve your goal? OTOH I’ve also been told that one should take faster, shorter steps while ascending, which would somewhat counter this effect. OTOOH maybe a short step is better on the joints than a long step. Then opting for steps that are both short and effortful could reduce a workout’s total joint-impact.
Oh, and obviously you (and your legs?) don’t move as fast. Maybe that is another contributing factor.
Did I get that right, or am I missing something?
I think poor form when running on flat ground is also a component. It is easy to magnify your impact by over striding, which happens less on ascent.