Sometimes it's hard to do a trail run and have that run be only on a trail surface. 

You can't always run a trail run…entirely on a trail. What I mean by that is that you have some pavement, some asphalt, some road, or whatever, that you have to run on in order to get to the actual trail part.  

It ends up being a mixed trail run.

Mixed trail runs can put you at risk of an over-training injury.

Today on the Doc On the Run Podcast, we're talking about avoiding injury on mixed trail runs.