Which is worse for my Achilles running hills or stairs?

This episode comes from a question sent in by a runner who was listening to the Doc On The Run podcast.  This is a runner who had an Achilles tendon issue and was recovering and getting back to running.  He has recovered enough that he is back to running, he's doing better, he's running without any pain, but he wanted to incorporate some strength training in the form of either hill repeats or running stairs. He wanted to know... Which is worse for my Achilles tendon, running hills or running stairs? Today on the Doc On The Run podcast, we're talking about which is worse for your Achilles tendon, running hills or running stairs.