When I strained my hamstring, I wore compression shorts for running and other exercises, but I don't like them. They do, indeed, do a good job of muscle support for your hamstrings, but they totally SUCK at ball support (about the only time I've been critical of something and used "balls" and "Suck" in the same sentence!) I dunno who invented them or why they're so popular, but all they do is press your nutsac IN and down, whereas a good ol' American JOCKSTRAP lifts your balls and pouches them properly. I say, "Let's get back to jockstraps, America!" Comp shorts are a poor substitute.