[mlyle]

Concrete is particularly awful, even with decent shoes... but that's what sidewalks generally are and people generally run on sidewalks.

Even asphalt is so much better.

[bobjob]

Concrete is awesome. No roots, flat and a predictable response (non) on hitting it. Just do not strike with your heels first and train slowly and methodically(not just running, this is true for walking as well).