What's the Difference Between Pronation and Supination?

Pronation and supination are normal joint actions that occur in two areas of the body: the forearm and the foot. However, excessive pronation or excessive supination can cause problems, especially with the feet.

Runners in particular need to be concerned about overpronation and supination, as either condition can impact their gait, leading to problems with lower-body mechanics and possibly injury.

In the upper body, pronation occurs when the wrist rotates posteriorly and turns the palm down (with a 90-degree bend at the elbow). When this happens, the radius crosses diagonally over the ulna (two bones of the forearm). Turning a door handle is an example of pronation in the forearm.

In the lower body, pronation refers to the natural inward movement of the foot. Pronation occurs at the subtalar joint, located directly below the ankle.

When you take a step forwards, your weight moves from the heel and distributes itself forwards and slightly inwards through the ball of the foot, where you push off with help from your big toe. This is called normal pronation, according to the American Academy of Orthopaedic Surgeons.

During normal pronation, the foot should roll inwards by 15 percent or less, so that the whole foot touches the ground briefly before you push off.

Overpronation of the foot occurs when the foot rolls in too much (eversion), placing excess pressure on the arches and increasing the risk of injury, particularly if you spend a lot of time on your feet every day—either during work or training.

People with flat feet (little to no arch) are at higher risk for overpronation. And when you overpronate, your arches can collapse even more. And runners who overpronate excessively are at risk of developing plantar fasciitis, iliotibial band syndrome, shin splints or knee pain, according to a May 2019 study in PLOS One.

If you're an overpronator, you may want to consider getting a stability or motion-control shoe. These shoes control the motion in your foot to varying degrees and help you minimise your risk of injury.

• Stability running shoes are recommended for overpronators. They're designed to support the arch of the foot through the midsole that may also extend into the heel.
• Motion-control shoes are recommended for those with severe overpronation. They provide arch support in the midsole but also offer additional heel cup support.

Getting the right shoe for your gait and foot mechanics can help you move more comfortably through daily activities and perform better in sport. For instance, in a 12-week study that included 226 participants, researchers found that the Nike React Infinity Run—a shoe with stability and motion-control features—reduced running injuries by 52 percent.

When the elbow is bent at a 90-degree angle and you rotate the wrist so that the palm faces up, you are supinating. With the arm relaxed alongside your body, supination would cause your wrist to rotate so that the palm faces forwards (anterior).

In the lower body, supination is the normal outward rolling of the foot (inversion). During running, supination occurs during the push-off phase of your gait, when the heel lifts off the ground and your body weight moves to the lateral (outside) edge of your foot.

Oversupination, sometimes called underpronation, happens with a greater-than-average outward roll of the foot. People with high arches are at higher risk for oversupination.

Overpronation is more common than oversupination, but it should still be addressed if you fall into this category. That's because oversupination, like overpronation, puts you at higher risk for injury, especially plantar fasciitis, according to a November 2014 study from Foot and Ankle International.

When shopping for shoes for supination (or underpronation), many people look for shoes that accommodate high arches. Generally, you'll want a shoe that offers plenty of cushioning, especially through the midsole. A wide toe box can also be helpful, as it can help support the foot, absorb impact and promote more pronation.

Check out neutral shoes like Nike Air Zoom Pegasus or Zoom Vomero to take advantage of their shock absorption, cushioning, and arch and ankle support. Or, try Nike React Infinity Run, which provides a wider toe box for optimum stability.