It’s easy to get hooked on running. We all come to love the start-line adrenaline, downhill thrills, and the reward of the finish line. But what starts as straightforward shuffling can quickly descend into technicality, as shoe salespeople and podiatrists babble about foot posture.
Overpronation and supination (underpronation) are two types of foot landing tendencies. In contrast to neutral pronation, overpronation distributes too much weight to the inside of the landing foot. Supination distributes the weight excessively to the foot’s outer edge. Both increase the risk of injury.
While these landing styles are inadvertent, they are by no means inevitable. Learning how they occur and how to treat them is easy and saves much damage and off-road time in the long run.
In this guide, we look at overpronation vs underpronation. What’s the difference? And when should we be concerned that our foot posture is affecting performance?
What Is Pronation – Overpronation vs Underpronation?
To understand both overpronation and underpronation, we need to understand pronation – the baseline behavior for foot landing while moving. Understanding the norm helps us characterize the deviation which we’re interested in.
When walking or running, the body acts as a self-propelling lever. Its mass moves forward in the sagittal plane, rotating along a fulcrum provided by the landing foot – being the foot placed in front during the walking or running motion.
While walking, bother feet are in contact with the ground at the time of landing. This distributes most but not all of the body’s weight to the front foot. In contrast, runners land from a position of both feet off the ground, leaving the landing foot to rotate all of the body’s mass.
All walkers and many runners land with the heel. Many endurance runners opt for a midfoot strike, in which the foot lands slightly to the front of the heel. In all cases, pronation involves rolling the foot on the ground in a diagonal path from the middle of the heel to the inside of the big toe. The body weight is concentrated along this path.
In order to achieve this diagonal forward distribution of weight, the landing foot rolls slightly inward between impact and lift-off. The extent of the tilt range from 15%-30%, depending on the evenness of the terrain. Flat terrain requires a tilt at the shallow end of the range.
What Is Overpronation?
Overpronation is pronation on flat terrain at a high angle in the 15-30% range. Extreme overpronators might exceed this range. Note that overpronation is a natural adaptation to help the body move across uneven terrain. It is a problem only insofar as it is triggered when the evenness of the ground does not require it.
Overpronators roll their ankles too far down and in with every step. This causes the foot to keep rolling at the time when the toes should be triggering push-off. Consequently, the burden of lift-off shifts entirely to the big toe and second toe, exacerbating the twist on every step.
Overpronation could cause strain on the heavily-loaded big and second toes and leave the foot lacking stability, resulting in poor running form. The exaggerated rotation triggers more tibial rotation in the lower leg.
What Is Supination?
As with overpronation, supination allows the foot to manage mobile weight distribution on uneven – in this case, convex – ground. Opposite to overpronation, supination (or “underpronation”) involves rolling the foot on its outside edge during the step.
During supination, the sole of the foot faces inwards, away from the floor, and towards the ankle of the opposite foot. Viewing the front of the leg during supination shows a big toe angled inward and an angle with outward alignment relative to the midline. Triggering supination requires adduction, plantar flexion, and inversion of the foot.
It is natural for runners and walkers to supinate during the toe-off phase when the heel lifts the ground. This outward tilt provides leverage which helps to roll the toes off.
With supernation, however, the foot is not sufficiently pronated at the toe-off stage. As a result, there is an excessive distribution of weight and work to the smaller toes and front edge of the foot.
What Are The Risks Of Overpronation And Supination?
Because overpronation and underpronation involve the application of force to joints that were not designed to endure the strain, repeated stress exposes the athlete to the risk of one or more of the injuries listed below.
Repeated complaints of the symptoms are a sign that the athlete may be insufficiently compensating for pronation error.
Plantar Fasciitis
The plantar fascia is a thick tendon connecting the heel to the toes. This creates an arch in the foot. Stress on this tissue – which can also come from excess weight or poorly cushioned contact on hard surfaces with normal pronation – causes this tissue to tear and become irritated, leading to heel pain.
Characteristic symptoms of plantar fasciitis are stabbing pain in the heel. Usually, this is most pronounced during the first steps of the day. As the tendon warms and becomes supple, the pain subsides. Plantar fascial pain may also be triggered from prolonged periods of sitting, after long hours on the feet, or following intense physical activity.
This is one of the most common sources of ‘soreness’ that newbie runners try to push through.
Iliotibial Band Syndrome
The iliotibial band (also known as Maissat’s band) is a long fascia (channel of connective tissue) running along the outside of the leg between the hip, knee, and shinbone. It helps with extension, rotation, and hip abduction. It features critically in protecting the outer thigh and helps with stability.
Illiotibial band syndrome (ITBS) occurs when the IT band rubs against the hip or knee bones, causing irritation. This rubbing occurs when the tendon becomes too tight and is drawn against the moving bones.
There are numerous potential causes for this, one of which is when excessive inward flexion of the foot – overpronation – tightens and inverts the IT band. This shows how an error in pedal posture can make itself feel as far up the kinetic chain as the hip.
Patellofemoral Pain Syndrome
PPS refers broadly to a set of complaints relating to pain in the front of the knee and surrounding the patella (kneecap). It is also known as “jumpers’ knee” or “runners’ knee” as athletes in these activities are exposed to and complain of it. The stiffness and pain make it difficult to perform everyday activities like kneeling and stair climbing.
Theoretical models have shown a link between overpronation as it affects the mechanics of the knee. In the models, this distortion of the knee disrupts the normal working of the patellofemoral joint. It is believed that overpronation triggers a compensatory internal rotation of the femur, as well as a reduction of patellofemoral contact in knee abduction.
Shin Splints
Shin splints manifest as stress-induced aching and throbbing of the shinbone and surrounding connective tissue that attaches its muscles. The affected tissue inflames, resulting in pain.
See more: how to treat shin splints with compression socks
Evidence links anterior shin splints to supination. During the gait cycle, the muscle that inverts the foot for late ground clearance (the tibialis anterior) will elongate and tear under the stresses of supination. These stresses arise due to the angle of incidence of the heel as the foot strikes the ground.
Overpronation triggers posterior shin splints. This is consistent with general flat-footedness during running, which causes the arch of the foot to disappear.
Other Injuries
Common other injuries that may derive from pronation error include:
What Causes Overpronation And Underpronation?
Overpronation and supination are equally distributed, i.e., no individual has different pronation traits in each foot. A variety of factors cause pronation errors. We list the leading ones below:
How Are Overpronation And Supination Treated?
The five interventions to combat pronation error are:
Posture
For runners, developing a posture that minimizes heel strike and weight loading is helpful in reducing the likelihood of pronation error. The basic idea is to take short steps, landing the foot under the center of mass on a flexed knee.
This alignment immediately makes it harder to land on the rear part of the heel, and the lighter impact reduces the need for weight adjustment.
Weight Management
Weight reduction lessens the impact that the arch needs to deal with. It increases the chance of gradual flexion of the arch in the arc of normal pronation.
Shoes
The selection of shoes is key. Most shoes are built on the assumption of a normal gait. When one has overpronation, extra care should be taken in the selection of shoes. This is especially so when the shoes will be used in activities such as running and walking that involve repeated foot strikes.
Stability shoes offer extra stability and support for athletes with pronation errors, minimizing the impact of each step. It is advised to browse for shoes at the end of the day, when they are more swollen, and to wear thin socks when fitting the shoes. Footwear offering arch support is to be preferred.
It’s also important to change your shoes once they show signs of wear, tear and stability loss.
See more: how often should I change my running shoes?
Orthotics
Orthotics are devices that are fitted inside a runner’s shoes. These may be either prefabricated or custom-made. Usually, the orthic spans the length of the foot, featuring an elevated arch for control of pronation error. They are made from soft foam, semi-rigid thermoplastics, or rigid carbon-based materials.
Exercises
The following exercises help condition the body away from over and underpronation:
- Push against a wall with one straightened leg behind the body and the other bent forward in front. Push towards the wall until you feel a stretch in the unbent rear leg.
- Alternate legs through repetitions with your shoes off, stand alongside a wall for support. Bend your front leg with the foot down, and bend the rear leg with the tops of the toes and front instep, touching the ground. Bend forward and hold the position for ten seconds. Alternate legs through repetitions.
- Sit unshod on a chair and cross your legs. With your hand, flex the toes of the raised foot backward and hold for ten seconds. Alternate feet.
How To Determine Your Pronation Type
It is important to check in with your pronation style before injuries arise: The following methods can be used:
- Professional Help: Consult a podiatrist to do a professional assessment.
- Video: Place a phone camera at foot level behind a treadmill. Run at a comfortably challenging pace with your shoes and socks off. Observe your pronation at the end of the video.
- Wet Foot Test: Leave an impression of your wet bare feet on a surface. This will show you how much of your arch lands on the ground. The more rectangular and blob-like the impression, the more prone you are to overpronation. Supination will show in a foot with a lot of empty space where the sole is.
- Wear: study the wear patterns on used running shoes. Shoes are worn at the outer edges signal supination. Wear on the inner edges is from overpronation. Normal gait shows wear that snakes from the heel to the big toe.
