Of all the small things that athletes fret about—training, rest, nutrition—feet seem to fall low on the list. Aren’t those ten little toes just there to help us balance, stay upright, and move forward, backward, and side to side? It turns out, not even close. As an athlete, the intricate movements of your own two feet play a major role in performance and injury risk.
You may see the term "overpronation" gaining notoriety in the athletic world as a risk to athletes, but it’s biomechanical opposite, "underpronation" (also called supination of the foot), may have similar effects on your risk of experiencing an athletic-related injury.
There are natural movements that the foot undergoes during a stride as you run.
When the foot hits the ground, the arch begins to flatten, helping to lower the extra stress; it’s a shock absorption mechanism. Weight then begins to shift to the outside of your foot, it then “rolls” back to the big toe—this is known as pronation. To produce force and help us push off from the ground, the arch rises and stiffens while our foot lifts up and rolls back to the outside of the foot; this is supination. The second and big toe complete the propulsive job at takeoff, launching the foot up while other toes stabilize and provide balance. Who new that the motion of the food could be so complex?
Pronation is normal. The inward rolling of the foot acts like a shock absorber, lessening the impact forces during running and preventing your poor knees and shins from absorbing huge amounts of shock due to the high impact of running.1
A foot that underpronates or has too much supination throughout the entire foot contact time is not normal. Supination occurs when the foot neglects the inward roll during the foot contact cycle. If you have too much supination, you land on the outer edge of your foot, and the foot continues to ride on the outside edge during the entire stride. Weight is never transferred to the big toe and all of the work is done by the weaker toes and outer edge of the foot.
Why is this an issue?
In athletes who supinate, the stabilizing smaller toes become the active pushing toes. Unfortunately, they aren’t designed to handle this type of stress.
As a result, knee pain, ankle sprains, and foot pain are common.
While supination is less common than pronation, it is still a problem in athletes—particularly those who may have a higher arch of the foot and and are stiff or flat footed.
If you experience excess supination of the foot, you’re not an alone, nor are you some kind of anatomical weirdo. Several athletes may lack an inward roll of the foot while moving due to a variety of reasons.
You may have inherited your tendency to supinate. Certain traits that affect foot and leg mechanics such as leg length, foot width, ankle stability, and poor form can cause supination. Leg length discrepancy (having one leg shorter than the other) may result in a mechanical compensation—more supination occurring in the foot on the shorter leg side.
Having a flat foot or high arches may also predispose athletes to supinate. Why? High-arched and less flexible (i.e. stiffer) feet alter normal foot biomechanics by preventing beneficial motions like pronation. A high stiff arch can’t ‘flatten’ normally and roll inward on contact. This can have consequences—it has been shown that high arched athletes who supinate have lower ankle muscle strength and peak torque, and experience stress fractures, knee pain, and lower-leg and foot problem as a result.2
Lack of flexibility in muscles of the feet and legs are known to cause supination as well. Tight calf muscles, tight achilles tendons, and rigid soft-tissue (like the plantar fascia) restrict movement.
Think you’ve gotten over a previous injury?
A past athletic-related soft tissue injury, ankle sprain, or stress fracture may come back to haunt you by causing structural weaknesses and a tendency for too much supination.
Ankle sprains are relatively common in athletes. Following an ankle injury, many athletes suffer from functional ankle instability (FI)—the ankle is never as strong as it once was. Supination is more common in athletes with ankle FI than in those with normal ankle stability.3 This is a chicken-or-egg problem, supination might alternatively lead to ankle instability by altering normal motion of the foot while running.
Other injuries that result in a restricted ability of the foot to move normally can lead to supination. Athletes who have a history of plantar fasciitis have less range of motion, lower peak torque (foot spinning motion) and a deficit of normal foot mechanics.4
Few things are more important to an athlete than proper footwear, but having ill-fitting running shoes may actually lead to problems like excessive supination. If you’re wearing athletic or running shoes that are too tight, this may restrict the motion of your feet. “Motion control” shoes and those with rigid arches might be harmful to athletes who don’t need them. Shoe inserts, while often recommended, may only lead to more foot pain. Supinators likely already have “rigid” arches and feet. More structure is the last thing they need.
Typically, athletes who supinate should look for a relatively cushioned yet neutral shoe that allows the feet to roll inward freely.
Supination may or may not lead to injury, but the risk is sure there. Runners with too much supination have a 77% greater odds of injury compared to their fellow pavement-pounders with "normal" foot biomechanics.5
Certain types of injury and pain might be clues that you supinate, and most of these occur because of the extra stress placed on the outer edge of your foot, leg, and knee.
Frequently ankle sprains or rolls, swelling in the ball of the foot or arches, and development of calluses or bunions on the outside of your foot might signal supination. These may be more irritating than pathological, but could lead to more issues later on. Excessive knee pain, back pain, and iliotibial band syndrome (IT band) are common in athletes who supinate.
Supination places extra stress on the ligaments connecting your heel and toes, known as the plantar fascia. This leads to an eponymous condition called plantar fasciitis. This manifests as as stabbing or aching heel pain and discomfort and along the arch of the foot.
Feeling pain in the front of you legs? Anterior leg pain, or shin splints (felt on the outer and front portion of the leg) might be caused by supination. Excess stress transmitted onto the bones and muscles of the shin area in supinators cause irritation of this area. Leg pain ensues.
Athletes who supinate or who have risk factors for supination like high arches and uneven leg lengths suffer more stress fractures. This may be a result poor form on top of inadequate motion of the foot. The metatarsal bones of the foot and the tibia seem to be most prone to stress-fracture.6
Suffering from an achilles tendonitis? This may also be a sign that you supinate too much. Underpronation of the ankle and foot was found in 21% of athletes suffering from a ruptured achilles tendon, compared to only 5% of those with a "normal" foot movement. 10% of these athletes also had high arches.7
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Invasive lab tests are not required. Determining the motions of your foot while standing, running, and walking is easy, inexpensive, and can give you and idea of how your foot moves and whether or not you need a bit of fixing up. While more severe issues may warrant a trip the the physical therapist at your nearest sports medicine clinic, you might want to try these simple at-home tests first.
The answer to whether or not you supinate can be easily found in your shoes.
Take a pair of your running shoes or trainers and look at the bottoms. If you supinate, the wear patterns on these shoes will feature a prominent “wear and tear” on the outer edge of each foot.
Finding less rubber and tread at this area? You might be a supinator.
The shoe "tilt test" can also be used to diagnose supination (or pronation). Take your current pair of athletic shoes, and rest them on an even surface. If your shoes tilt to the outside, this indicates supination. A more prominent inward tilt indicates overpronation, the opposite condition.
Looking for a more technical or professional diagnosis? Having your foot biomechanics evaluated by a running specialty store or podiatrist may be a good idea, especially if you want to work on correcting issues related to supination with a professional.
Many running specialty stores will observe and record your feet while running and walking, what is referred to as a gait analysis. This visual assessment can make clear any excess supination you may have. A specialist can also tell you if you’re in the correct pair of running shoes and, if not, prescribe a different fit or model to accommodate your particular stride.
A pressure scan, usually done in a podiatrist's office (or more simply using a brown paper bag and some wet feet) can indicate where you are placing the most stress. Unfortunately, this is normally just done while standing, and might not represent any abnormalities you experience while running. However, this is a great test to diagnose a flat foot or to indicate if you’re placing extra stress on the inside or outside edge of your foot.
Disrupting the "normal" movements of your body is often not advised. However, in the case of supination, correcting some of the indirect causes like improper running shoes or muscular weakness will result in improved motion of the foot without forcing a drastic change in running form.
We’ve already discussed that for supinators, flexible and lightweight sneakers with a reasonable amount of cushion are probably best. These will allow sufficient ankle motion and foot / arch flexibility while running, while still providing adequate foot and arch support as you pound out the miles.
The risk of “over controlling” feet for supinators is real. While injury risk is lower in athletes who pronate and wear motion control shoes or orthotic inserts, these corrective measures show no effect on injury risk in athletes who supinate.8 In fact, high-arched people (more prone to supinate) who are placed in motion control shoes are actually at a greater injury risk than those in neutral shoes.9
Replace running shoes regularly. When you begin to notice the outer edge wearing down, it’s time to invest in a fresh new pair.
Depending on the volume and intensity of your activity, this might be every six months or so, perhaps even sooner.
The idea that we are “born to run” is theoretically satisfying, and may also carry some application when it comes to training your mechanics as an athlete.
Since supination and the injuries related to it may occur due to foot and ankle instability, training that improves the strength of the arch of the foot and other stabilizing muscles will be beneficial. Barefoot training builds strength in the feet and lower leg, stabilizes small muscles in the foot and ankle, and improves joint mobility. When running barefoot, you’ll naturally resort to a shorter stride length, a higher cadence, and place lower loads on the body,10 a result of landing softer and lighter, like running on eggshells.
Every so often, training barefoot (on soft surfaces) can teach your body to run in a way that minimizes the loading forces at the lower extremity that may be greater if you supinate (and even if you don’t). Barefoot training may also ingrain proper foot mechanics to reduce the amount of supination that occurs while you run.
Be careful. Too much barefoot training, too soon, can lead to injury. Allow the body time to adapt to the new load experienced by the feet and legs which are used to being wrapped in protective cushion for most of our lives. Expect a bit of soreness in the lower leg and arch of the foot initially as you begin to incorporate one or two days per week of low-volume barefoot training into your routine. This might be in the form of barefoot running, strength training while barefoot, or just easy barefoot walking on the grass.
Currently, there is little evidence that barefoot running reduces injury risk compared to running in shoes.11 However, a small amount of barefoot training may be best to implement beneficial patterns. Just don’t be too quick to ditch your kicks completely.
Working to change your form can be time-consuming, risky, and even detrimental to performance. Performing certain drills and implementing some movement tweaks may help prevent foot pain and injury caused by supination.
You definitely didn’t hear it here first—as an athlete, you should probably stretch.
Supination is often caused by overly tight muscles; particularly tight calf muscles and a tight achilles tendon. Tight muscles restrict your range of motion, resulting in an inability of the foot to spin inward and flex. Adequate and regular stretching of these problems area, as well as the quads, hamstrings, and ilio-tibial (IT) band can help to release areas that might be contributing to supination. Moving back and forth over a foam roller is a fantastic, dynamic way to stretch muscles pre-exercise—anytime, really.
Improving ankle flexibility through stretching, massage, and foam rolling can also help promote proper foot mechanics and prevent supination. Weakness and ankle instability are a major cause of supination.
Before starting any activity, massage your feet, arches, and ankles to break up soft tissue adhesions and warm up these areas—this will promote mobility. For tight arches, a tennis ball might become your best friend. Use it to roll out the soles of your feet before you compete. This trick is among the many recommended to stretch and strengthen intrinsic muscles of the feet, a strategy found to reduce symptoms of plantar fasciitis in 29% of patients in one clinical study.12
In order to prevent problems related to the high impact forces on the lower leg that occur due to supination, it’s necessary that athletes build strength so they can handle the stress better.
Building strength in the inner thigh with exercises like lateral leg raises (with ankle weights) can help to correct gait patterns. The front of the leg, prone to shin splints in supinators, can also become more robust and help ease the impact load of running and other activities. Try exercises like heel step-downs, resistance exercises using bands, and wall shin-raises to work the muscles around the shin.
Any exercise that strengthens the entire leg will also benefit your gait and lower the stress related to excess supination. Squats for the quads, front and lateral lunges, and calf raises are all exercises to incorporate into your routine—even if you’re not a supinator.
It’s unlikely you will change the entire mechanics of your foot or gait to completely eliminate excess supination and poor form. Exercises and stretching may help alleviate symptoms, but never entirely fix the problem. Smaller tweaks to form, along with exercises, may be the best defense, rather than a panacea.
Altering your cadence, the amount of steps you take per minute while running or performing any activity, might reduce symptoms of supination. Shorter steps result in a lower impact force, and keep each foot on the ground for a shorter amount of time. This likely means lower incidence of stress fractures, reduced knee and hip stress, and a less injury-ridden athlete.
The foot is an engineering marvel. Without it, running, sprinting, and jumping would be impossible. When natural movements like supination sometimes run amiss, problems ensue. Knowing the causes and remedies for problems you may be experiencing related to supination / underpronation, you can now take action to improve your longevity as an athlete and optimize your performance and enjoyment of sport.
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