Risk Factors for Stress Fractures and Shin Splints – not what you think.

Last month, a study was published which followed 230 high school runners. Over a 3 year period, almost half of them (102) developed shin splints bad enough to take them out of running for at least one week. In addition, about 10% of them (21) developed stress fractures in their shins.

I treat many high school kids in the clinic with shin splints, and the overwhelming home remedy that they have tried is over the counter orthotics. They are repeatedly told that they are “overpronating”, they have “flat feet” or their “arches are collapsing” and that is the cause of their shin problems.
Is everyone with these injuries overpronating? What do the studies say?

The study mentioned above looked at many factors at the beginning of the study and then followed the runners for 3 years. One of the factors was called “navicular drop” (the navicular bone is a bone in the foot which near the height of the inside arch of the foot. As you run/walk, the foot is supposed to deform and the arch lower a bit. Measuring the amount of “drop” in the navicular will indicate how much the arch deforms) The results of this study showed that navicular drop was in fact, NOT associated with a higher risk of shin splints or stress fractures.

Other studies have shown the same thing: Like this study here. However, other studies show that the amount of navicular drop test DOES correlate: Such as this study here or this study here

So, confusion exists on whether the arch deformation contributes to shin problems . Some studies say “yes”, some say “no”, however, if we step back and look at these studies, were they done on patients who are actually running? Most of the time the answer is “no”. However, we know from previous studies that the static (non-moving) arch height has virtually no correlation to the arch height when running.

So far, all I’ve shown is that there is basically non-agreement on pronation and arch height deformation with shin problems. However, even if we were to “pretend” that it did, what would be the solution? More often than not, the answer is to put the runner in arch molds/footbeds/orthotics. Is that the answer? Not according to this study found here. In fact, that study found that there was actually an INCREASED risk of shin splints in those runners who used orthotics. Yet, another study showed that orthotics provided relief for people with shin splints.

So, there is little to no consensus on whether or not floppy, loose, overpronating feet correlate to shin splints and tibial stress fractures. There is also little consensus on whether or not orthotics help. There are other factors though. Two examples (not a complete list):
1) Impact loading rate. This has been shown to correlate well to stress fractures. Impact loading rate can be modifiable through changes like cadence, where your foot hits the ground, knee excursion etc.
2) Training errors (too much, too soon, too fast). Training errors have been reported to account for as much as 60% of all running injuries.

The only fact is that there is not “ONE” factor associated with these injuries. One has to take a look at the individual’s training and biomechanics and navigate through the maze of information. Maybe it’s time for an appointment with Running Reform?