Trail Running

According to much of the literature that I have read, running on grass, dirt, gravel, etc. is supposed to be easier on the body. I personally think it is just another marketing scheme to get us to buy a different kind of shoe. Here's my reasoning. Two Saturdays ago the local running group I run with on occasion decided that the nice smooth asphalt was no longer acceptable. The snow had melted sufficiently that a trail nearby was dry enough to run on. 

Anxious to test out the theory that my feet and knees would appreciate this run, I committed to be there. I suppose a nice well run trail would be easier , but after running on various angles, up and down and maneuvering around semi-frozen mud holes, my feet and legs felt like crap. My ankle definitely didn't appreciate the change. Maybe its my shoes...I should definitely look at getting a pair of trail running shoes or maybe I should just stick to the streets.