resistance slows you down, as long as there is something stable enough to resist against, which may or may not be the face of a bump. The physics become complicated because our feet are slamming into the face of the bump, which may or may not be perpindicular to the direction of momentum; and the CoM is higher up and is only being deflected by the legs which are attached to the feet that are hitting the face of the bump. So a lot of complicated things can happen depending on numerous factors, but will result in some amount of upwards acceleration, acceleration back up the hill and probably the introduction of toppling as well.
but what we can say is that if you absorb 100% cleanly, then you eliminate the bumps ability to push you back, up or trip you into toppling. Resist the face of the bump with pressure, and it does effect you. None of this is all or nothing, as cgeib eluded too, you can be partially absorbing and partially embracing some pressure, and not neccessarily the same way at say the base of the face of the bump versus as you are cresting the top. This makes a big difference because a bump has a round shape, so near the bottom the face is facing more directly back up the hill but as you approach the crest its facing more up in the air.
Edited by borntoski683 - 4/21/15 at 8:02pm