I've had shin problems ever since I started running years ago, but now I think it might be compartment syndrome??? it stayed healed for awhile though once I took a year off running but now Any run at any pace or form style is cut short of a mile due to my lower leg muscles giving out. it's always some form of my shins,calf's, feet/ankles giving out and making me legs feel like dead weights *no spring* . My upper legs never get sore, and I can run the 400 meter in 55secs and back off and float another lap. I've ran the mile in 4:00 flat once and want to break it one last time