I don’t care who you are or where you came from, going downstairs and downhill is harder than going upstairs or uphill. This is because the muscles that control that motion are working very differently. The same muscles control the action of ascending and descending something, but descending is harder. Ever hear the expression “same shit, different day?” Well, here it’s “same muscles, different action.”
My mom says when her knee is hurting it hurts worse going downstairs. That’s because she using the quadriceps muscle eccentrically. When I climb stairs, it’s much harder and feels much less stable descending stairs. That’s because I’m using the quadriceps muscle eccentrically.
If you don’t have a brain injury and tore your ACL or something, going downstairs will be harder. If you have perfectly uncompromised muscular and neurological systems, going downstairs and downhill will be harder. It might seem like it should be easier to walk or run downhill because of the momentum but you have to control the motion with eccentric contractions and they’re hard.