Someone told me that wearing spandex shorts can help reduce injury because it keeps your butt, upper thigh, and IT band warmer (and thus more loose) than regular running shorts. Is there any validity in this? I have definitely noticed that more girls wear spandex on the East Coast than on the West Coast. I went to high school on the West Coast, and went to the East Coast for college. I refused to wear spandex until I had to start racing in tiny bunhuggers (yuck!)...because only spandex shorts fit under running tights, so I would still have an intermediate layer between my warmup tights and racing spankies.