they are tiny hair fractures in your bone around your shin. its caused from the stress your legs receive when your foot hits the ground. its more common in 'flat-footed' people. You can get shin splints while running on any surface.

The only way to really prevent them is to change your running style. Having shoes that absorb the stress, or having inserts that absorb the stress is just a way to lessen the intensity; its not really a cure for the problem.


edit: meant or exnbp

-web md says that shin splints are inflamed muscle fibers, but they also have been known to caused fractures in your bone.