It seems as though i can run pretty well but when it comes to jumping in that negative gravity I cant do it any tips

if you need help in jumping, rolling, flips and sliding... you can offcourse pm(private message) me and we can do parkour in multiplayer and ill try teach you somethings, but im not a big pro in parkour xD

First off, you should have space for the jump.

Second, try to constract both hips and make like a jump movement, try to move your abs, your knees and your ankles(Hips can be relaxed or holded)

Third, Waste 10 or 15 frames to prepare the jump(abs can help and hips too)

Then you will be able to jump. Extend your knees, raise your hands, relax pecs if necessary.
then try to help with your hands to reach the point.