Why do race horses running on synthetic surfaces have more hind leg and soft tissue injuri

Why do race horses running on synthetic surfaces have more hind leg and soft tissue injuries ?

I found a very informative article released today about this very thing. There are many opinions about synthetic tracks, but this helps give statistics.

http://www.signonsandiego.com/news/2010 ... el-debate/

Source(s):
Lifelong horse racing enthusiast