Tibialis Posterior Pain/Dysfunction
Have you ever come back from a run and had pain on the inside of your foot or ankle? It may ache into the arch of your foot and feel sore if you try to point your toes. This could be caused by irritation to the tendon of the Tibialis Posterior muscle; a muscle found deep in the posterior compartment of the lower leg. It originates from the back of the both the tibia and fibula leg bones, runs down behind the inside ankle bone where it is secured by a thick band of connective tissue called the flexor retinaculum. It attaches onto the navicular bone of the foot, wraps under the arch to the medial cuneiform and the bases of the 2nd- 4th toe metatarsal bones. All sounds a bit complicated but basically any pain on inside of ankle into the arch of the foot could be related to this muscle. Mainly irritated in runners by over use but in the non running population there are certain risk factors that elevate your risk of developing tib post problems.
Tibilais Posterior helps plantarflex the ankle (point your toes) and invert your foot (turn the bottom of your foot into your midline). It is also the key stabilizer of the medial arch of the foot. Dysfunction of this muscle can lead to a dropped arch.
As with most running injuries this muscle can be injured through overload. Poor running style, weak/tight calf muscles, muscle imbalances in the body, lack of strength can all lead to this muscle being overloaded. This can cause the tendon to become inflamed and irritated leading to a tibialis posterior tendinopathy. Without addressing this the muscle is unable to keep the arch stabilized which can lead to a flattening of the arch putting further pressure on the tendon. The tendon can become so damaged that it eventually ruptures and you are left with collapsed arches.
During walking, as your foot strikes the ground the tibialis posterior engages to support the arch of the foot as the foot moves through pronation into supination. Both normal parts of the gait cycle. There is relatively low load when walking.
The Tibialis Posterior works in harmony with the muscles on the outside of the ankle, the peroneals. During running, the speed that pronation occurs is quicker and more forceful so the tibialis posterior has more work to do to support the medial arch through this movement.
Runners who are overweight are at higher risk and poor form can have an impact on the load going through the tibialis tendon. Poor running form is often linked to a low cadence and overstride. This creates a braking force and means the foot is on the ground for a longer period of time. The Tibilais Posterior has to support the foot as the body moves over the foot.
Strengthening the muscle in the foot and also further up the chain can help to reduce the load being placed on the Tibilais Posterior. On Friday I’ll add some videos on how to strengthen the tibialis Posterior and how to improve your running form to help offload the tendon.
If you have any questions about the Tibialis Posterior please leave them in the comments. Rehab is about adapting your exercise so you can tolerate it and offloading the part of your body that isn’t happy. Seeking advice early on is key to getting the right treatment and preventing symptoms becoming chronic.