Can Arch Height Predict Your Running Injuries?
The “Wet Test,” in which you assess the shape of your wet footprint to determine if you have high or low arches, has somewhat fallen out of fashion in running circles in recent years.
It used to be that people with low arches were assumed to be “over-pronators” and were assigned motion control shoes, while people with high arches were assigned cushioned shoes. But in parallel with the rise of minimalism around 2010, a series of studies found that this type of shoe prescription didn’t seem to reduce injury risk. These days, you’re more likely to hear advice along the lines of “Buy a shoe that feels comfortable to you when you run.”
But the dismissal of arch height’s prognostic value may have been a bit premature. For example, a more rigorous 2016 study from Luxembourg, which included disguised “placebo” shoes, found that motion control shoes did reduce injury rates, particularly in those with low arches.
And there’s a more subtle point. “Did you get injured?” is an important question; but so is “What type of injury did you get?” As a new study in Medicine & Science in Sports & Exercise, from researchers at the University of Memphis and Virginia Commonwealth University, points out, the height of your arches seems to play a role in the type of injury you’re most susceptible to.
In general, high-arched runners tend to get bone-related injuries like shin splints and stress fractures in the shin and foot. Low-arched runners, in contrast, tend to get soft-tissue and joint injuries like Achilles tendinopathy and runner’s knee. This observation dates back at least to studies in the late 1990s and early 2000s.
What explains this differences? High-arched runners tend to run with “stiffer” legs: If you think of the legs as a giant spring, high-arched runners don’t bend their knees as much and their centre of mass doesn’t go up and down as much with each stride. These are very subtle differences, but can be enough to affect which parts of the body get overloaded.
The new study sought to determine what explained the differences in stiffness. The researchers performed a sophisticated biomechanical analysis on 10 high-arched and 10 low-arched runners, all female midfoot or forefoot strikers. (This is a curious detail, since rearfoot striking is much more common. It would interesting to know if the results would have been different in rearfoot strikers.) With this data, they calculated how much of the lower leg’s spring stiffness was attributable to the bones in the leg, and how much to the muscles.
As expected, the high-arched runners had much stiffer legs, by almost 50 percent, than the low-arched runners, meaning that the high-arched runners ran with much less up-and-down motion. But the difference was entirely explained by differences in skeletal stiffness, meaning that the forces were absorbed by the bones – which is consistent with the idea that high-arched runners get more stress fractures.
In contrast, the relative contribution of muscle to lower-body stiffness was higher in the low-arched group, consistent with the higher prevalence of soft-tissue injuries like Achilles tendinitis.
The big question, then, is what you should do about it. For starters, it’s worth being aware of your arch status. If you have an abnormally high or low arch, and you’ve been perennially suffering from injuries typically associated with that condition, maybe it’s worth trying to address it.
Will switching shoes to the “right” one for your foot type help? I don’t know. It might be worth a try, at the very least. The researchers suggest the possibility of “altering running and landing biomechanics to reduce skeletal or muscular loading.” That’s an interesting proposal, but one that needs to be tested out in studies (and explained in more detail). On a related note, I wrote a couple of years ago about the concept of strengthening your “foot core,” which is a possible way of raising your arches.
So are we back to prescribing the Wet Test? Perhaps, but hopefully not in the simplistic way it was sometimes prescribed a decade ago. There’s no simple, guaranteed connection between your arch height (or any other foot or stride parameter) and your injury destiny or your shoe needs. But there are risk factors that may tilt your odds one way or another – so if you struggle with recurring running injuries, knowing your arch height may offer one more clue to help you sort them out.
Finding the Perfect Pair of Running Shoes
Use these tips to make sure you’re picking out the perfect pair for your feet.