Bunions are a common cause of pain in the side of your foot while you run. The protrusion of the big toe joint is often associated with women's footwear. Even if you don't wear heels away from the track, the miles of impact you put on your feet while you run can also cause this painful foot condition.
Significance
Bunions can cause significant discomfort and pain. They can become so painful that you might have trouble putting on running shoes. The deformation in your big toe can progress to the point where surgery is the only option for effective treatment.
Symptoms
Bunions cause pain and tenderness on the side of your foot, next to the first joint of your big toe. The joint will push sideways, away from your foot, pushing the top of your big toe towards the mid-line of your foot. In severe cases, your big toe may become so misaligned it effects the alignment of your other toes.
Causes
The force put on your feet while you run can cause the first joint in your big toe to splay. Tight shoes and high heels can also push too much pressure on this joint, eventually causing joint misalignment.
Treatment
Realigning the big toe helps take pressure off the bunion and increases blood-flow. You can realign your toe by putting a separator between your big toe and second toe and taping the separator to your big toe.
Shoes should provide enough room to prevent excess pressure on the bunion, relieve pain and help prevent further misalignment. You should have enough room in your toebox to fit a finger or two between your big toe and the top of the shoe. Your shoe should also be wide enough so it doesn't put pressure on your bunion. It's alright if your shoe touches the side of your foot, but it shouldn't cause pain. If needed, have your shoes stretched out to provide room for your bunion. Many footwear retailers provide this service.
Prevention
Reduce your mileage if you feel pain on the side of your foot in your big toe. Make sure your shoes provide adequate support and replace them before they wear out and compromise your feet. Look into orthotics, especially if you are prone to over-pronating, which puts extra pressure on your big toe when you push off during your stride. Orthotics slide into your shoes, often in replace of your insoles, to provide your feet with additional support and help correct biomechanical problems, such as over-pronation. You can purchase a pair at your footwear retailer or have them made specifically for your feet by a doctor.


