What is a subtalar joint sprain in a runner?

Ankle sprains are incredibly common in runners. Sprained ankles account for about 10% of all musculoskeletal injuries that show up in the Emergency Room. But there is another injury that can seem sort of like an ankle sprain, but doesn't respond to treatment the same way.  This sprain is not in the ankle. It is a sprain of the joint under the ankle...the subtalar joint. It's called a Subtalar Joint Sprain. What is a subtalar joint sprain in a runner? Well, that's what we're talking about today on the Doc On The Run Podcast.