These have amazing support for their weight. Because they go up pretty far, a bit above the waist, they really hold your back steady and the crisscross seams stabilize your knees perfectly. But what really surprised me was how they managed to compress my hamstrings and quads while still being perfectly comfortable (as compared, say, to Under Armour compression tights, which I find uncomfortably tight, yet less supportive because the support's un-directed, just pressure). I'm fat-ass out of shape but these tights felt so good that I ran intervals in them, which normally would mean hobbling soreness for days. But with these, the next day, presto, I felt fine. For really hot weather, I like the ventilated stabilyx shorts, but the 3/4s aren't roasting--yesterday was in the low 80s and I didn't overheat. Oh, and I would recommend going a size smaller than you think you need: they're quite stretchy except in the target zones. The chart has me as a solid medium (5 9, 165) but trying them on at the Backcountry store in SLC I liked the tightness of the smalls and I'm glad I went that way.