UnderArmor is starting to slide down when I run because my waist is shrinking.  It comes in "one size fits most athletes."  I'm NOT SMALL for a runner (BMI ~19.5--small long distance runners are more 17.5-18), but I'm getting curvier (because I lift, too), and I don't have a big enough waist anymore to keep it where it belongs.  So unless I can get it smaller, I'll have to stop and yank the crotch up again every couple of miles.  It's really pissing me off because they were expensive.  I used to run regularly but haven't lifted in (waaaay too many) years, so I didn't realize it would be a problem.