If you recently started getting some aching pain on the outside of your ankle every time you run, you might have a condition called peroneal tendonitis. 

Peroneal tendonitis is a problem often encountered by runners with high arches. It can often be exacerbated by running in ultralight unstable shoes or running on trails when you're feeling too tired to maintain good form.

The two peroneal tendons are both on the outside of the ankle. But they do different things. The way you position your foot to reduce the stress and strain on the one injured tendon, will have to be different because they each do different things.

Today on the Doc On The Run podcast, we're talking about how to tell the difference between the peroneus longus and the peroneus tendon when you're a runner.