Shin Splint Treatment: How Improving Calf Strength Can Fix Your Shin Splints
Shin pain, or “shin splints,” is a common and frustrating problem for a lot of beginning (and experienced) runners. It’s one of the most common ailments in runners, from sprinters all the way up to marathoners.
While there are a variety of remedies out there for shin splints—more properly referred to as “medial tibial stress syndrome”—the purpose of today’s article is to highlight some recent scientific studies that point to an easy method of preventing and treating shin pain: calf strength.
How calf strength influences shin splints
Impact forces bend the tibia
The shinbone, or tibia, absorbs a lot of shock from impact during running.1 As a result, it’s particularly prone to injuries, both mundane and serious.
A recent scientific review by Maarten Moen and colleagues at a medical center in the Netherlands concluded that shin splints, viewed as an irritating but ordinary problem, and tibial stress fractures, a serious bone injury, are actually caused by the same phenomenon: bending of the tibia during running.2
Now, the tibia doesn’t bend like a wet noodle; it’s more like a bridge under strain. After your foot hits the ground during running, the force traveling up your legs puts stress on your shin, causing it to bend slightly backwards. The degree to which your shinbone bends with a given impact depends on two factors: how thick the bone is, and how well it’s supported by the muscles around it. Fortunately, having strong calf muscles helps on both of these fronts.
Running helps you develop stronger muscles and bones
With all the talk about the evils of impact and the dangers of running injury, you might be under the impression that runners are risking their bodily integrity in pursuit of their goals.
But it’s quite the opposite.
Runners, and anyone else who participates in a high-impact activity, have stronger and denser bones than sedentary people. That’s because bones adapt to the stresses they encounter during your daily activities. And stronger muscles means thicker bones, as shown by a 2009 study by Kristen Popp and coworkers at the University of Minnesota.3
In this study, Popp et al. used CT scans to examine the bone thickness and muscular cross-sectional area (a more quantifiable measurement of muscle size) in female runners with a history of stress fractures, mostly to the tibia, then compared these runners to ones who had never suffered a stress fracture.
The results showed that the previously-injured women had smaller bones, but more importantly, smaller muscles than the never-injured runners. In fact, when the researchers looked at bone size relative to muscle size, there was no difference between the two groups! So, the tibia “grows” in response to the size of the muscles around it, and the calves are by far the largest muscle group surrounding the tibia.
Calf muscles support the tibia
The calf muscles also make the shinbone more resistant to bending by resisting and redirecting some of the forces on it.
Getting back to our bridge analogy, the calf muscles are like the strong cables on a suspension bridge. When the muscles tense up, as they so during impact with the ground, they counter the bending forces that are attempting to deform and strain the tibia. So, in theory, runners with stronger calf muscles will be more resistant to shin injury.
This hypothesis was put to the test in a 2007 study by Luke Madeley, Shannon Munteanu, and Daniel Bonanno at la Trobe University in Australia.4 Like Popp’s study, Madeley and his two fellow researchers compared two groups of runners: one with shin splints, and one without. Both groups were asked to complete as many consecutive single-leg calf raises as possible, with the researchers ensuring they didn’t “cheat” by going too low or leaning forward.
As predicted, the injured runners averaged only 23 calf raises, with the healthy runners averaging 33—a difference of 30%!
Calf strengthening as a treatment for shin splints
So, calf strength should be considered as a serious treatment and prevention option if you are prone to shin pain. Even if you’re healthy now, it’s an easy and simple way to ward off future injury.
Unfortunately, there’s no standard protocol as of yet. But doing single-leg calf raises to failure, like the runners in Madeley et al.’s study, once or perhaps twice a day is a good place to start.
Stronger calves looks as though they will will “straighten up” your shinbone in the short term, preventing the kind of bending that causes excessive strain on the tibia, and strengthen your lower leg bones in the long run, making them more resistant to injury.
Finally, if you’ve had severe shin pain for a week or more, you ought to see a doctor to ensure it hasn’t developed into a stress fracture (especially if the pain is localized to an area only an inch or two in size). It usually takes high-tech imaging to diagnose a stress fracture, and they are definitely not something you want to try to run on.
1. Milner, C. E.; Ferber, R.; Pollard, C. D.; Hamill, J.; Davis, I. S., Biomechanical Factors Associated with Tibial Stress Fracture in Female Runners. Medicine & Science in Sports & Exercise 2006, 38 (2), 323-328.
2. Moen, M. H.; Tol, J. L.; Weir, A.; Steunebrick, M.; De Winter, T. C., Medial tibial stress syndrome: a critical review. Sports Medicine 2009, 39 (7), 523-546.
3. Popp, K. L.; Hughes, J. M.; Smock, A. J.; Novotny, S. A.; Stovitz, S. D.; Koehler, S. M.; Petit, M. A., Bone Geometry, Strength, and Muscle Size in Runners with a History of Stress Fracture. Medicine & Science in Sports & Exercise 2009, 41 (12), 2145-2150.
4. Madeley, L. T.; Munteanu, S. E.; Bonanno, D. R., Endurance of the ankle joint plantar flexor muscles in athletes with medial tibial stress syndrome: A case-control study. Journal of Science and Medicine in Sport 2007, 10 (6), 356-362.