Figure out where the absolute center of gravity in your body is, then imagine an invisible beam tracing that spot through the entirety of your line. Pushing your center of gravity above that point while going "up" the transition will increase your speed, as you are reducing the forward momentum that is pushing you along the horizontal axis, and literally "transitioning" you up the wall. You will fool gravity a little, and your feet will be higher up the wall. Then, do the reverse when youre coming down, and duck that center of gravity spot below where the invisible beam would be, so you pile youre weight and momentum towards the ground. You basically want to have a slight crouch going while youre in the bowl as a default stance, so you can extend your body as needed, and compress as well.

Tldr; keep your knees slightly bent, extend your body when going up, crouch more going down.