How can pronation cause hallux rigidus in a runner?

One time at a medical conference, an expert lecturing on biomechanics said,  “When a runner develops Hallux Rigidus, he becomes a swimmer instead of a runner.” Most of the doctors in the audience laughed. I really didn't think that was very funny. I actually have hallux rigidus myself, and it doesn't disrupt my running. It is true Hallux Rigidus can cause pain and swelling in the big toe joint. If you aren't careful the joint can get destroyed. If you understand a little bit about the mechanics of the joint, it may help you understand how to avoid the arthritis that can hamper your ability to run in the future. How can pronation cause hallux rigidus in a runner? Well, that's what we're talking about today on the Doc On The Run podcast.