These babies are the reason I can do a 2.5 hour hills workout on a Saturday, and hammer with a group on Sunday. I'm known by my friends as a true believer in compression wear, and have been known to wear these for extended periods (during a 22hr road trip to a race, for example). I am not 100% sure on the science for these things, but they work. REALLY WELL. They feel absolutely incredible after a hard workout. I would not recommend wearing them while working out; I tried doing that, and it felt like I had to work against the compression. I've never paid the full price for a pair, but they are worth it if you are serious about recovery and being able to work out at your best.