As a former HS runner, HS track coach and now HS parent with children running I've been around the running community for over 20 years. I've noticed my body (knees in particular) don't hold up very well running on hard surfaces (cement/asphalt). It severely limits the amount of quality miles and runs my body can handle before it breaks down. However, on grass or dirt surfaces my muscles may get sore/tired but rarely if ever do I experience injury. As a result, if I can't make it to a place where I can be primarily on soft surfaces I'll prefer to run in circles (half mile loop) at a local park instead of heading out to the roads. It may get boring but at least it limits injury. I've seen the same thing occur in HS runners, but the subject seems to be taboo for HS coaches to discuss.

What are your thoughts on running on hard surfaces vs. soft surfaces? What have been your experiences?