By Dev K. Mishra, M.D.
President, Sideline Sports Doc
Clinical Assistant Professor of Orthopedic Surgery, Stanford University
Shin splint syndrome and stress fractures in the foot and leg are common in runners. I have been seeing a large number of these injuries in high school athletes, especially towards the end of cross country or distance running seasons. Both shin splints and stress fractures are characterized as overuse injuries. These injuries happen with repetitive loading (meaning: running), and the pain or fracture occurs when the load exceeds the foot or leg’s ability to withstand the load.
Shin Splints or Stress Fracture?
Runners with shin splint syndrome typically have a generalized discomfort or pain along the inner border of the lower leg bone, the tibia. A ‘shin splint’ refers to inflammation or microtears at the site where muscle inserts on to the inner portion of the main leg bone, the tibia. Usually the pain comes on gradually over a number of days or weeks, and often increases to the point where pain is present even with light daily walking.
A stress fracture refers to a crack in a bone that typically starts from repetitive overload. A stress fracture in the foot or leg can come on suddenly and often has a very localized area of pain or discomfort.
In my opinion shin splint syndrome and stress fracture are somewhat related because a runner with ongoing shin splint syndrome who attempts to continue training and competing can go on to develop a stress fracture. There is a concept in biomechanics called ‘tibial shock’ in which loads are repetitively delivered to the tibia during running. If the loads exceed the leg’s ability to withstand them the initial response is usually shin splints, and if continued repetitive loading occurs the next structure to fail is the bone. I like to think of leg pain in runners as a spectrum ranging from relatively mild and annoying to the most severe condition, a stress fracture.
Causes: Too Much, Too Soon Combined With Mechanical Factors
When we look at runners with shin splints or stress fracture we like to try and identify the cause of the problem so it can be avoided when the runner gets back to running. The most common training factor is a recent increase in training intensity or duration. Other factors may include a recent change in running style or change in running shoe. When intensity or duration increases too rapidly, that means the bone was subjected to ‘too much, too soon.
Another very common cause is flatfoot and/or overpronation during running. With an overpronated foot the muscles along the inner portion of the leg will contract to provide support for the arch. With continued use this support can become overstressed, leading to injury.
What To Do
If you’ve had a sudden onset of what you would describe as localized pain in the foot or leg, I would recommend that you see a sports medicine specialist prior to starting any treatments. This could be a stress fracture and needs proper evaluation before you do anything on your own.
But if you have a nagging discomfort on the inner aspect of the leg this could be a shin splint. For discomfort that’s only been present for a week or two you should back off your mileage significantly or stop completely. Cross train with an AlterG Antigravity Treadmill or elliptical trainer until pain free. Use a ‘stick’ for self massage. Wear a calf support during exercise. And use Superfeet or similar arch support if you have flatfoot. When you restart running you need to start with a very low mileage and intensity, then ramp up no more than 10% per week, as long as you remain pain-free. If these simple measures are not successful, if your pain increases, or if you have pain lasting more than about 3 weeks I’d recommend that you see a sports medicine specialist.