Hi, this has never happened before and I don t know what to make of it. I have a bruise on each leg and they are in the same spot, directly behind the knee. Each bruise is a thin line, about an inch long. It also hurts to straighten my legs and to walk. It sort of feels like I have cramps behind both knees, the kind of cramps you get when your muscles are very tight. I did some weight lifting, exercises for my calves, two days ago. Everything was find until last night. 24 hours after the exercising. Do I need to be concerned? Could this be an indication of significant damage behind my knees? Damage to tendons, etc ...Thanks for your help.