Clinical Relevance of Overpronation

If you’ve ever worked with competitive runners or others with active lifestyles, you’ve likely encountered the term overpronation (also called hyperpronation). Overpronation can be a challenging biomechanical pattern leading to multiple lower extremity disorders. It can also be an incidental finding that exists, but is not causing a person’s current pain complaint. The trick for clinical practitioners is to figure out when it is a relevant factor, and when it isn’t. First, we must understand what overpronation is.

Pronation and supination are anatomical direction terms more commonly associated with movements of the forearm and wrist. However they are also applied to the foot and ankle region, but in a much different way. Pronation of the foot and ankle complex occurs naturally during the walking or running gait. As a result it really isn’t accurate to say a person has problems because they pronate their foot, as most people do pronate as a normal part of walking. The problem occurs when there is too much pronation. Overpronation (hyperpronation) indicates pronation movement that is excessive or happens too rapidly during gait cycle. However, there isn’t agreement in the science literature about what excessive movement really is and how to define it, so this is still an issue in accurately describing overpronation.

In the forearm, pronation is a single plane movement where the wrist and hand turn over. However, pronation of the foot and ankle is more complicated. Pronation in the foot is a movement that doesn’t occur in just one of the three cardinal planes: sagittal, frontal, or transverse. It is a diagonal movement that moves through all three planes. Consequently, it is defined as a combination of dorsiflexion (in the sagittal plane), eversion (in the frontal plane), and abduction-more commonly referred to as turnout of the foot (in the transverse plane) (Figure 1). So, pronation is a diagonal plane movement that occurs in multiple planes during normal gait.

Figure 1
Three movements of pronation: dorsiflexion, eversion, and abduction

The diagonal movement of pronation is more easily visualized during a non-weight-bearing position (Figure 2). It is a little more challenging to visualize pronation when the foot is in a weight-bearing position because the foot can’t move freely through space. Pronation occurs during the mid-stance (weight-bearing) portion of the gait cycle. In a weight-bearing position instead of the foot moving in relation to the leg, the foot is stationary on the ground and the leg moves in relation to the foot in the same diagonal plane across the foot.

Figure 2
Pronation in a non-weight bearing position

Primary Causes

Overpronation occurs when the body moves too far or too fast through the pronation movement during gait and may lead to dysfunctional biomechanics and various pain complaints. Causes vary, but there are a number of important factors that may increase the risk of overpronation.

One of the most common causes of overpronation is functional weakness of the tibialis posterior muscle, which is in the posterior compartment of the leg deep to the gastrocnemius and soleus. It plays a critical role in foot mechanics. Anatomy texts will often say that its primary actions are plantar flexion and inversion of the foot. However, one of the most important things it does is control the amount of foot pronation during gait, essentially putting on the brakes (eccentric action) for the pronation movement.

When a person overpronates it is often because the tibialis posterior is not doing an adequate job of resisting the pronation movement. In these cases there may be an excessive load on the muscle that is transmitted to its attachment site along the tibia and will this can oproduce medial shin splints (periostitis) because of constant pulling on the periosteal tissue at the attachment site.

While the tibialis posterior is certainly a key factor in resisting overpronation, it doesn’t work completely alone. Ligaments of the ankle complex also restrain excessive movement between bones and contribute to foot stability and prevention of overpronation. There is a group of ligaments on the medial side of the ankle which are collectively referred to as the deltoid ligament because they create somewhat of a triangle (the Greek letter Delta) in their shape. These ligaments have an important role in resisting excessive calcaneal eversion which is a significant component of overpronation. Calcaneal eversion is explained later in the article.

Previous sprains or genetic factors of ligamentous laxity may cause the deltoid ligament group to be looser than normal, thereby producing hypermobility of the foot and ankle complex. This hypermobility can easily contribute to overpronation. The deltoid ligament complex is not sprained as frequently as the ligaments on the lateral side of the ankle, but they can certainly be involved in ankle injuries and become overstretched and contribute to overpronation.

Excessive weight is another factor that may lead to overpronation. The architecture of the foot and ankle is designed to distribute the body weight across the foot during the gait cycle. However if a person is significantly overweight, the soft tissues which maintain the foot’s arch are not able to withstand the compressive loads and the arch can collapse causing the foot to roll toward the medial side. The loss of an adequate arch can be seen in a static standing posture and is also called pes planus or flat foot. Keep in mind you don’t have to be overweight to have pes planus as people can have this type of foot architecture genetically. The excessive medial roll of the foot is even more apparent during the gait cycle and this is when the overpronation occurs as the foot rolls too far toward the medial side during its weight-bearing stance.

Foot architecture is not the only biomechanical challenge that can lead to overpronation. Faulty knee alignment is another cause. Genu valgum, also known as knock-knees, causes a change in the way weight is distributed through the lower extremity (Figure 3). Because the knees are bending inward, there is a tendency for more weight to be pushed toward the medial side of the foot, which can produce overpronation during gait.

Figure 3
Genu valgum (knock knees)
Image courtesy of Wikimedia Commons

A valgus angulation is one in which the distal end of a bony segment deviates in a lateral direction. At the knee, the valgus angulation is named for the lateral deviation of the distal tibia. There can also be a valgus angulation to the calcaneus where the distal end of the calcaneus deviates in a lateral direction (Figure 4). Calcaneal valgus is also called subtalar eversion. Calcaneal valgus is generally visible in a standing position and is best viewed from the back side of the heel. The will heel appear to be angling in a lateral direction. This postural deviation can also be viewed from the front side of foot and causes a small section of the heel to stick out toward the lateral side of foot and since only a small portion of it is visible sticking out to that side it is sometimes called a peekaboo heel.

Figure 4
Posterior view of the right foot showing lateral deviation of the distal calcaneus in calcaneal valgus
Mediclip image copyright (1998) Williams & Wilkins. All Rights Reserved.

Overpronation can also be a cause of other lower extremity disorders. Plantar fasciitis, tarsal tunnel syndrome, Baxter’s neuropathy, and posterior shin splints may all be aggravated from overpronation, especially in runners. There is also a strong likelihood that overpronation plays a major role in a condition called hallux valgus, which eventually leads to the formation of bunions on the medial side of the foot at the metatarsophalangeal joint.

As noted above, there are structural challenges that may point to the possibility of overpronation. However, because pronation is really a dynamic movement and not just a static position, it is best evaluated during the gait cycle, such as watching a person’s foot strike and gait pattern on a treadmill. However, that is generally not practical for most massage therapists. Another factor that can be helpful in recognizing overpronation is examining the wear pattern on the bottom side of the client’s shoe. This will only work if the shoes have been worn a significant amount so that some wear pattern is evident. A person who overpronates will tend to have a greater degree of wear on the medial side of the shoe.

Treatment Considerations

In traditional orthopedic approaches, overpronation is generally addressed with orthotics to help change the biomechanical pattern of the foot and ankle complex. The goal is to re-stack the foot and ankle complex in a more vertical position and prevent it collapsing towards the medial side and overpronating during weight bearing.

Another common treatment strategy is to encourage strengthening of the tibialis posterior and other associated muscles that resist overpronation. It is challenging to target this specific group of muscles, but various foot and ankle movements can be done with varying levels resistance to help develop greater strength in these muscle groups. There can be a fundamental error with this approach, however. You can develop greater strength in a muscle group, but if the motor pattern ingrained in the nervous system still allows for dysfunctional mechanics and perceives this as normal, increasing strength in those muscles is not necessarily going to change the dysfunctional mechanics. As a result, the person is still likely to continue overpronating. If the strengthening is done in conjunction with orthotics or other interventions that alter motor recruitment patterns, there is a greater likelihood that they will have lasting results.

So what role does massage or soft-tissue treatment play in addressing overpronation? While there are no research-based treatment protocols, there are a number of common suggestions for helping overpronation with massage. Suggestions include moderately deep and tissue-specific compression and stripping techniques along the plantar surface of the foot and along the tibial border to access the deep posterior compartment (Figure 5). The described intention of these approaches is to increase extensibility of the tissue and make it free to move and reduce overuse trauma. However, a primary issue in overpronation is that the tibialis posterior is not functioning adequately to resist overpronation, so the problem is not that the muscle is too short or contracted. Therefore, the goal may be to reduce hypertonicity, but generally should not be to increase too much extensibility in that tissue.

Figure 5
Deep longitudinal stripping along the tibial border to best access tibialis posterior

There are some massage technique descriptions which advocate stimulating the muscle and encouraging it to ‘turn on’ or increase motor activity and gain strength. However, there is no significant research to support the idea that any massage technique can strengthen a muscle. That doesn’t mean that massage is not beneficial in addressing overpronation, but the way in which we use it for this purpose may be different than what we generally think of.

Our understanding of the primary effects of massage has changed in recent years. Some of the most profound effects seem to be mostly associated with changes in the nervous system. Consequently, these approaches are helpful to improve proprioceptive responses from the foot and ankle complex to adjust faulty biomechanical patterns. Yet, remember that just because a person is overpronating does not mean there is a pathological issue that has to be fixed. Many people can function just fine with less than ideal biomechanical patterns. The key challenge for us is to determine if it is a mechanical pattern that is leading to other soft-tissue pain and injury problems or if it is an incidental finding that may not necessarily be a root cause of the client’s current complaint.

Changing the neurological and motor control associated with a particular biomechanical pattern is a complex process. We now recognize that many soft-tissue interventions aren’t mechanically changing tissue as much as they are helping make new connections in the brain and nervous system with how the tissues feel and function. Massage therapy remains one of the most powerful and effective strategies for soft-tissue intervention, so despite the fact that we may not be changing structure within the body significantly, what we’re doing in treating conditions like overpronation is still incredibly valuable.