Just coming back from the mystery hip injury, ran stadium stairs today. I say 'mystery' since I find it less painful to run stairs than to jog on the flat. Whatever this is, I think I'm over the hump and will be on the track again next week. The hip felt better after this light workout. With a classic hip flexor strain, it should hurt to run stairs, but it doesn't, only a little when I get to the top. So that's why I call it a 'mystery injury.' I may seek evaluation, really don't want to spend the $. MRI's are a $450 deductible on my health plan.