Running used to be the most accessible form of exercise. All you needed to do was put on gym clothes, lace up your sneakers, and head outside. The Tarahumara tribe of Mexico makes it even easier than that—they don’t wear much more than a piece of leather on the sole of their feet to run 100 mile marathons! Are the rest of us spending too much time trying to match our footwear to our foot? Should we just get outside and move?

Pronation, specifically overpronation, has long been considered a risk factor for foot injury. Choosing footwear based on individual foot type is often the first step in combating potential injuries. Foot posture compatibility with shoe design has been identified as the most important factor in choosing a running shoe by nearly 75% of cross-country runners but may ultimately be unnecessary for most people.

foot anatomy

Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013.
Image by OpenStax College

 

Pronation definition: supination vs pronation

The foot is a complex, triplanar joint. Pronation, a normal motion at the ankle joint, is the combination of eversion at the subtalar joint, dorsiflexion of the talocrural joint, and abduction of the forefoot. The opposing motion, supination, is a combination of inversion at the subtalar joint, plantar flexion of the talocrural joint, and adduction of the forefoot. Simply put, when the foot rolls inward after making contact with the ground, it is pronating; as the individual transitions from midstance to toe-off, the foot supinates to create a rigid lever for push off.

Normal pronation

man with normal pronation

Photo: Penny Goldberg

Normal pronation is difficult to measure because it occurs around three axes simultaneously.  Normal pronation has been described as 15% but without a clear reference point, this number is not useful. Instead of using percentage of motion, researchers have determined that pronation can be measured using a combination of other static foot postures, including navicular drop, navicular angle, calcaneal eversion, Achilles angle, and longitudinal arch angle.

Foot posture is often classified as pes cavus (high arch/supinator) or pes planus (low arch/pronator). Consistent deviation from neutral foot posture, either excessive pronation or supination, can lead to structural and functional deficits. Often, these biomechanical dysfunctions are seen in the joints and soft tissues above and below the problem area.

Overpronation

young man with foot overpronation

Photo: Penny Goldberg

Excessive pronation has been linked to overuse injuries in the lower extremity for as long as humans have been ambulatory. This extra range of motion is thought to cause abnormal stresses to the medial musculoskeletal structures of the foot and ankle, as well as up the kinetic chain to the knees, hips, or low back.

A systematic review by Carvalho et al. reported that high-arch and low-arch foot postures are risk factors for developing running related injuries including medial tibial stress syndrome and plantar fasciitis. Yates and White studied military recruits and found those with a more pronated foot posture developed medial tibial stress syndrome more often than those with neutral foot posture.

A similar study found that in 25 female runners, those with a history of plantar fasciitis had a low arch or pronated foot posture, more often than age-matched controls. This suggests that identifying individuals who are excessive pronators prior to the initiation of training may be beneficial in decreasing the incidence of medial tibial stress syndrome and plantar fasciitis.

Overpronation is related to increased knee flexion during dynamic movements. This theoretical model suggests that the relationship between knee flexion and overpronation can be explained, in part, by the increased tibial internal rotation that occurs with pronation. Increased knee flexion values have been associated with higher patellofemoral joint compression forces which could be the link between excessive pronation and patellofemoral pain syndrome.

See more on patellofemoral pain syndrome.

Another connection between pronation and patellofemoral pain may be Q-angle, or quadriceps angle. Q-angle represents the angle of pull of the quadriceps and is both responsible for, and subject to, other forces in the lower extremity.

Prolonged time spent in hyperpronation creates increased internal rotation of the tibia which may lead to excessive medial knee stresses and lateralization of the patella from tight soft tissue structures. The combination of excessive Q-angle and overpronation may speed up the progression from knee pain to patellofemoral arthritis to degenerative joint disease or osteoarthritis.

Gait analysis

Structural abnormalities, and the atypical stresses associated with them, can wreak havoc on our joints. This is particularly true for joints of the lower extremity because of the sheer number of steps taken in a lifetime. Most people are familiar with the terms “knock-kneed” and “bow-legged” which refer to genu valgum and genu varum, respectively.

In genu valgum, the knees are touching with the feet spread apart from midline. In genu varum deformity, the feet are touching while the knees are spread apart from midline. The links between genu valgum, genu varum, and lower extremity injury is well-established, as is the increased incidence of osteoarthritis when the deformity is more severe. Both genu valgum and genu varum are associated with a pronated foot position.

When genu valgum and genu varum walking conditions were investigated the effects on the subtalar joint varied. In a simulated genu varum condition, the foot was placed more medially than it would have been with normal gait and the ground reaction force line moved laterally.

This change in ground reaction force created a shear force across the plantar surface of the foot that resulted in pronation as the foot tried to remain plantigrade. In a simulated genu valgum condition, the foot was placed more laterally than normal gait which shifted the center of pressure laterally and increased the pronation moment. At the same time, the ground reaction forces were medialized which decreased pronation.

Eighty-eight adults with knee osteoarthritis underwent radiographic examination of anatomical axis angle to determine its relationship with pronation. Researchers found that patients with medial compartment osteoarthritis (genu varum) had an increase in supination angle of the calcaneus relative to the floor.

This is contrary to conventional thinking which suggests that varus deformity creates a supinated foot, that becomes pronated as a compensatory motion, in an effort to keep the sole of the foot in contact with the floor. The discrepancy between prevailing theories and these findings may be explained by the length of the dysfunction as hindfoot varus (supination), is often present in end-stage osteoarthritis when the individual has lost the ability to compensate for the malalignment.

Leg length discrepancies are also a potential source of dysfunction in the lower extremities. Calcaneal inversion and eversion, critical components of supination and pronation, do not seem to be altered by leg length discrepancies.

In the case of leg length discrepancy, foot pronation or supination can be a compensatory mechanism where the individual may pronate on the longer limb to functionally shorten the leg, or supinate on the shorter limb to gain functional length. The knee and hip may also adjust to leg length discrepancies through flexion at one or both joints to shorten the longer limb.

In the absence of these postural deviations, the pelvis will be lower on the shorter side which creates scoliosis as the individual strives to keep their eyes on the horizon. In the interest of minimizing gait deviations and postural alterations along the kinetic chain, individuals with leg length discrepancies may be best served with a heel lift to correct the leg length discrepancy.

Do you need to “correct” overpronation?

There are several ways that overpronation can be directly or indirectly corrected. Not all structural deviations are problematic, thus, the decision to correct overpronation lies in the amount of disruption to normal routines and/or dysfunction that is being caused.

During gait, the quadriceps muscle group eccentrically controls knee flexion during the loading phase as the posterior tibialis actively decelerates pronation, and the gastrocnemius resists anterior translation of the tibia. In an overuse injury situation, it’s easy to see how the patellar tendon, posterior tibialis tendon, and achilles tendon could be overworked. Slight deviations from a neutral foot posture over thousands of foot strikes can lead to overuse injury which suggest there comes a point where correction is warranted.

The effects of overpronation are not limited to the lower extremities. A study of 35 healthy males looked at the immediate effect of hyperpronation in standing, which revealed that during subtalar pronation, the calcaneus everts which causes the talus to move medially and inferiorly.

The researchers found that increases in bilateral pronation caused a compensatory phenomenon where increases in sacral angle, pelvic inclination, lumbar lordosis, and thoracic kyphosis were all observed.

They theorized that the movement of the talus creates internal rotation of the tibia and subsequent internal rotation of the femur causes the femoral head to put pressure on the posterior acetabulum. The pressure on the acetabulum causes the pelvis to tilt anteriorly to allow more room for the femur to sit comfortably.

Anterior tilt of the pelvis will draw the sacrum anteriorly as well, which could result in hyperlordosis of the lumbar spine. An increase in lumbar lordosis can result in increased thoracic kyphosis to keep the head in position over the sacrum and the body upright. Anterior pelvic tilt may also lead to  lower-crossed syndrome. Lower-crossed syndrome describes the muscular imbalances associated with anterior pelvic tilt: tight hip flexors, hamstrings, spinal erectors, and calves along with weak abdominals, gluteals, quadriceps, and foot stabilizers.

Another research group hypothesized that anterior pelvic tilt and increased lumbar lordosis would be present with pronation, while posterior pelvic tilt and decreased lumbar lordosis would be present with supination. The researchers evaluated 15 participants in 18 foot positions and failed to find a link between pronation or supination, anterior or posterior pelvic tilt, and lumbar lordosis.

They manipulated inversion/eversion positions of the calcaneus but were unable to induce alterations in pelvic tilt under test conditions. It is generally accepted that changes to the sacral angle and changes in lumbar lordosis occur concurrently, however previous studies that evaluated small changes in pelvic tilt have also failed to establish this relationship. It seems that changes in pelvic posture induced by manipulating calcaneal inversion/eversion need to reach some unestablished baseline magnitude to be observable.

It has also been suggested that individuals with flat feet may have dynamic balance deficits. Ottman et al. determined that those who spend too much time in pronation may have many muscles throughout their body that do not activate in the proper sequence. This has the potential to not only affect balance, but cause an increased work effort for all activities, including oxygen consumption during normal walking.

Pronation and orthotics

Orthotics that support the medial arch, change the position of the calcaneus, or do both may be the quickest, easiest way to decrease biomechanical stresses and alter foot posture. In most individuals orthotics can be used to bridge the gap between the source of the dysfunction and interventions to address it, including stretching, strengthening, neuromuscular re-education, and massage.

Physical therapy has been shown to be effective at improving pronation. A study of 41 individuals with pes planus investigated the effects of a six-week program of short-foot exercises on navicular drop, foot posture, and dynamic plantar pressures. The program resulted in decreased navicular drop, enhanced foot posture, reduced foot pain and disability, and increased plantar pressures in the midfoot. Another study on the effectiveness of a robust therapeutic exercise program in 58 adolescent pronators showed that all biomechanical parameters and gait improved with the 12-week program.

In evaluating runners for injuries, it appears that an awareness of foot posture during the stance phase of running, specifically at the point of maximal pronation, may be more clinically useful than trying to match shoes to foot type.

Ryan et al. evaluated the efficacy and safety of suggesting motion control shoes to distance runners. Their randomized control trial found that individuals in motion control shoes had more injuries and more missed training days than those in stability or neutral shoes.

A similar study found no difference in injury risk when shoe type was selected based on the shape of the foot compared to a group that used stability shoes regardless of foot shape.

More and more evidence suggests that training errors, not foot posture, may be the cause of up to 70% of all running injuries. Runners may be more well served to focus on training guidance instead of foot posture and shoe selection.

A Danish study of over 900 individuals who were novice runners investigated if running distance to first running injury varied between foot postures in neutral shoes. The participants were provided neutral running shoes and instructed to run without restrictions on distance, duration, or intensity. Injury incidence after one year was reported at: 17% for neutral, 18% for supinated, 25.5% for highly supinated, 13% for pronated, and 33% for highly pronated feet.

Also, pronated feet had significantly fewer injuries per 1,000 kilometer of running than neutral feet. The findings of this study demonstrate that, contrary to common beliefs, foot postures falling outside of the normal range did not have higher injury rates confirming that these “abnormal” foot postures are not always pathological.

Appropriate training loads combined with short foot exercises seem to carry the possibility of long-term improvement in pronation where orthotics may offer a solution without addressing the problem.

Foot pronation and massage therapy

As with every condition, it is important that the massage therapist performs a thorough evaluation and seeks to understand where and when their client is experiencing pain and dysfunction. Simply observing their anatomy and finding a pronated foot does not mean a pathological issue is present. The key challenge for massage therapists is to determine at what point these imperfect mechanics are leading to soft tissue pain or injury.

Massage therapy can be a useful adjunct for the treatment of overpronation, but it is critical that the therapist understand how the tissues are being affected so that they can choose appropriate techniques. In overpronation, tibialis posterior is not eccentrically resisting pronation like it should be, but the muscle is unlikely to be short or contracted. More likely, it is being overstretched by the collapse of the medial arch.

Massage techniques targeting posterior tibialis should focus on decreasing hypertonicity rather than increasing extensibility. Tibialis posterior is most effectively treated in side-lying with the affected side on the table so that the medial aspect of the leg is accessible.

If active stripping techniques are being implemented, it may be necessary to apply manual resistance through the plantar surface of the foot to elicit an appropriate level of contraction for the technique to be effective. Working on this region can be quite painful, so be sure to check with your client often regarding tolerance and proceed with caution.

Ideal biomechanical patterns are just that—ideal. Most individuals can function normally without pain or compensation despite having imperfect gait or lifting mechanics. It is important that the cause and effect of pronation are examined prior to intervention to ensure the most appropriate treatment plan is implemented.

Running may not be as simple as the Tarahumara tribe make it, but it is not as complicated as shoe companies would have you think either. If you are having pain in your feet or along the kinetic chain, meet with a healthcare professional who can help you understand your unique biomechanics and set you on the right path to keep you moving.

penny goldberg dpt
Penny Goldberg, DPT, ATC
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Penny Goldberg, DPT, ATC earned her doctorate in Physical Therapy from the University of Saint Augustine and completed a credentialed sports residency at the University of Florida. She is a Board Certified Clinical Specialist in Sports Physical Therapy.

Penny holds a B.S. in Kinesiology and a M.A. in Physical Education from San Diego State University. She has served as an Athletic Trainer at USD, CSUN, and Butler University.

She has presented on Kinesiophobia and differential diagnosis in complicated cases. Penny has published on returning to sports after ACL reconstruction and fear of movement and re-injury.

Outside of the clinic, Penny enjoys traveling, good cooking with great wine, concerts, working out and playing with her dogs.