Oh dude I thought you meant like 20 standing I was like holy shit! It’s super hard, seriously. Jim over at beastskills.com has an awesome tutorial for that one. Doing them on your knees will only get you so far because the leverage is different and it simply doesn’t generate enough tension. So instead of making the rollout on the knees harder, try it from the other end; try doing modified versions of the standing rollout to make it easier. One method that Jim suggests, for example, is performing standing roll outs on a sloped incline (like a driveway) so that you are rolling out uphill. There are several ways to approach this, so be creative! I actually found that I was able to do the rollout at a time when I was incorporating back levers and dragon flags in my workouts, even though I was not training the rollout itself.