how to fix player with foots under floor inside the ue4 editor?

hello, i’m having a little issue after retargeting some animations.

the issue is that some animations force the player go under the floor, i know how to fix this using 3d studio max, maya and motion builder (change the z position on each frame) but i’m trying to find a solution that works inside the ue4 editor.

here is a picture of the issue

i tried to change some values in the animation screen without any result.

anyone knows a way to fix this inside the ue4 editor ?

thanks in advance for all your help.