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The Thankless Posterior Tibialis

As another installment of the underrated, undervalued, and neglected muscles series, I am writing this blog to highlight the importance of another muscle for runners. In my last blog, The Soleus: An Unsung Hero In Runners, I discussed the importance of soleus muscle training in endurance athletes. Today, I wanted to focus on another muscle originating in the calf, but working on the ankle and the foot: the posterior tibialis muscle. This muscle is a bit infamous, mainly because it is frequently injured in runners. I am here to change that narrative and help you learn how training this muscle can not only reduce your injury risk for foot and ankle injuries, but also improve your balance, stability, and improve your running performance!

What is the Posterior Tibialis Muscle?

The posterior tibialis muscle is located in the deepest layer of our posterior lower leg muscle compartment. It is tucked deep behind our more superficial (and better known!) calf muscles, the gastrocnemius and the soleus. Our posterior tibialis muscle attaches between our tibia and our fibula, runs down our leg and behind the medial malleolus (medial ankle bone), before its tendon spreads out to its broad attachments in the medial arch of our foot. One of the most significant features of this muscle, is that it attaches throughout our arch including the navicular bone, our medial cuneiform bone, and the base of our 2nd, 3rd, and 4th metatarsals, contributing greatly to dynamic arch stability and control. Also because of its many attachment sites, this muscle can be a source of pain along the medial ankle, heel, or arch of their foot, and it is commonly overlooked when some people assume all arch pain is merely due to plantar fasciitis.

The Posterior Tibialis Muscle In Action

The posterior tibialis muscle is primarily responsible for inversion of the foot, or when the foot moves inward in the direction of your other foot. It also works with the gastrocnemius, soleus, and plantaris muscle to perform plantar flexion of the foot (aka push off). Another function, and perhaps the most undervalued role of the posterior tibialis muscle, is that is acts as the primary dynamic stabilizer of our rearfoot and our medial longitudinal arch. It must work eccentrically to control and prevent excessive inward collapse (i.e. excessive pronation) of the arch of the foot during single leg stance while walking, running, or jumping.

Now that we know what the muscle does, let’s talk specifically about its role during running mechanics. When running, this muscle is responsible for controlling pronation (combined motion of dorsiflexion, eversion and abduction) during the stance phase of running gait

and helping us move into supination (combined motion of plantar flexion, inversion, and adduction) for push off. From initial contact, when our foot first strikes the ground, throughout the stance phase, our foot moves into and out of pronation.

Many people think that any pronation during running is bad, however, pronating is NORMAL and is supposed to occur during running. It is one of the many ways that our body absorbs shock during runs. Ideally, at initial contact, our foot will pronate and will reach full pronation at mid-stance. Through mid-stance and into push off, our foot will begin to supinate, becoming more rigid in order to produce forward propulsion. Our posterior tibialis muscle is responsible for controlling the amount of pronation and how quickly it occurs, as well as assisting with supination that occurs for push off. When we have excessive pronation, we fall into pronation too quickly, or we are unable to come out of pronation for push off, this is where injury to this muscle (or other structures along the leg/kinetic chain) can occur.

Posterior Tibialis Muscle Dysfunction

Due to its large role in pronation control and force absorption, injury to this muscle unfortunately plagues many different high-impact sport populations that involve running and jumping. If we have weakness or poor control throughout our midfoot, it can become easily inflamed and irritated from acute injury or overuse. Injuries to this muscle can include pain along the inner ankle, heel, or medial arch, swelling located on the inside of the ankle, tendinopathy, and in extreme cases, flat foot deformity and rupture. We see posterior tibialis muscle dysfunction very frequently in the clinic, and it is most commonly caused by poor ankle mobility, training errors, and/or myscke weakness or compensation patterns. Dysfunction of this muscle is highly misdiagnosed and people often assume that the pain they are having is plantar fasciitis, shin splints, ankle sprains, arthritis, or ankle impingement.

Train Your Posterior Tib

If you have not picked up on this by now, it is exceptionally important to include this muscle in your strength training routine if you are participating in high volumes of running or jumping. This muscle must be trained to support our body weight plus additional impact forces AND be able to appropriately move us through our run gait mechanics. If it is not equipped to handle the loads of impact that it is asked to control during running, then it will eventually become dysfunctional. You can find some great exercises to begin strengthening this muscle and the surrounding muscle groups for prevention of posterior tibialis muscle dysfunction here.

Thanks for reading!

Dr. Allison Jones, PT, DPT


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