Underpronating can cause a whole host of injuries for runners.
Supination, also known as underpronation, is the insufficient inward roll of the foot while standing or after landing during a run. It may be the result of having a naturally high-arching foot, or it may also be caused by certain muscle weakness in your calves, ankles, or feet that are a result of ill-fitting running shoes, improper gait, or previous injuries.
If you’re a runner who is a habitual supinator, you place extra stress on the outer side of the foot, which can trigger a whole host of other issues you might not be aware of.
Here are some telltale signs that you may be an excessive supinator, along with advice for alleviating the harmful effects and severity of supination.
Your Shoes Lean to One Side.
When a supinator runs, the outside of the heel of their foot hits the ground first, says Steven Weinfeld, M.D., an orthopedic specialist at The Mount Sinai Hospital in New York City. Because the foot does not sufficiently roll inward after landing, the force of impact remains concentrated on that one specific part of the foot. An easy way to tell if you’re doing this regularly is if your running shoes wear out quickly and unevenly, with more breakdown on the outer side of the shoe.
In turn, this uneven wear of the shoe can make supination even worse (with less shock absorption where you’re landing) and reinforce a gait where the impact of landing isn’t distributed evenly. To check if your shoes have uneven wear, place them on a flat surface. If they tilt outward, supination is likely in play.
Bone Fractures and Ankle Sprains Are Common.
Because supinators place more pressure on the outer part of their feet, stress fractures on the fourth and/or fifth metatarsal—the large bones in the middle of your foot connected to your fourth toe and pinky toe—may have you heading to the podiatrist more often than you’d like. That’s because those tiny toes are doing most of the work when you push off while running.
Supinators may also experience a stress fracture on the fibula, which is the outside bone of your lower leg.
“A fibula fracture is not very common, but supinators may be more likely to stress this area,” says Marci Goolsby, M.D., a primary care sports medicine physician in the Women’s Sports Medicine Center at Hospital for Special Surgery in New York City.
In addition to triggering stress fractures, this extra pressure caused by supination can also diminish ankle stability and increase the likelihood of rolling or spraining an ankle, Weinfeld says.
You’re Stopped Cold by Shin Pain.
A supinated foot is less shock absorbent, Weinfeld says, and running on it repeatedly may, over time, cause lower leg pain commonly known as shin splints.
Shin splints occur below the knee either on the front outside part of the leg (anterior shin splints) or the inside of the leg (medial shin splints). Because supinators run with the majority of their weight on the outer part of their feet, they are more likely to experience anterior shin splints. (If you’re regularly dealing with the pangs of shin splints, caused by supination or not, try these simple exercises that will help sure up that problem spot.)
Your Calf and Achilles Are Super Tight.
This one is a bit of a “chicken and egg,” dilemma, Goolsby says. People with tight Achilles tendons and calf muscles tend to be supinators because the extra stress placed on the outside of your foot can radiate upward and contract your other muscles. Conversely, tight Achilles tendons and calf muscles may cause (or worsen) supination.
If you feel chronically tight in one or both of these spots, you may be a supinator—or at risk for becoming one.
You Have Stabbing Plantar Fasciitis Pain.
Supination can create extra strain on the ligament connecting your heel and toes, known as the plantar fascia. The result? Plantar fasciitis, a painful condition characterized by a sharp stab or deep ache in the middle of the heel or along the arch of the foot.
Plantar fasciitis is a common ailment for runners and can be caused by factors other than supination. Still, it’s worth asking your doc if there may be a connection.
What You Can Do to Help Your Supination:
It’s hard for the average person to know that supination is the underlying cause of any of the aforementioned issues, Weinfeld says.
“It often takes a physical therapist, podiatrist, or other doctor to study the foot alignment and diagnose the issue,” he says. A doc can perform tests to identify if you do indeed suffer from supination (these usually involve walking or running on a treadmill), and if so, how severe—or rigid—your supination may be.
Supinated feet that are “flexible” are easily corrected, whereas supinated feet that are “rigid” are much harder to fix, Weinfeld says. The flexibility or rigidity of your supination may be genetic—or it may be a factor of your age.
“People can start out with flexible supination that, as they age and their bones become more arthritic, turns into rigid supination,” Weinfeld says.
Once your supination has been diagnosed, there are several things you can do to alleviate the condition and its related ailments:
1. Incorporate strength training: “Perhaps the number one thing you can do to alleviate the negative effects of supination is strength train,” Goolsby says. “It’s important to be strong all the way through your kinetic chain.” She recommends focusing on glute and hip strengthening exercises that will bring greater stability to your ankle and feet, which are often the first areas stressed by supination.
2. Get the correct footwear: Replace your running shoes before they are significantly worn on the outer side, Weinfeld says. You may also consider visiting a specialty shoe store to get some advice. You’ll typically want to be in more cushioned or neutral shoes that allow your feet to pronate more. Many of the big brand names, like Nike, Asics, and Saucony have supinator-friendly shoes to get you going.
3. Consider orthotics In general, orthotics are trickier to build for underpronators vs. overpronators. “But sometimes there is a role for inserts,” Goolsby says. “The insert would be less corrective, but would focus more on providing cushioning and a comfortable surface area for your foot.” You can buy supination-friendly orthotics at a specialty shoe store, but a doctor will likely recommend custom-built ones.
4. Adopt a stretching routine: Stretching before and after you run is something every person should do, but it’s especially important for supinators. Regularly stretching your calves, Achilles, shins, and ankles can help alleviate tension that may be causing or worsening your supination.