I ride clipless because it feels so much better on my knees. Even a few laps around the bike shop parking lot unclipped on a test ride reminded me how much I prefer to be clicked in. It initially took a couple of weeks of minor tweaking, but after I got it just right it was like everything fell into alignment. Maybe I'm not "pulling up" but I do make a point to activate my hamstrings sometimes to relax my quads and relieve some knee pressure. Probably wrong, but works for me. One thing I don't see mentioned much that also helps me is watching my heel position.