Posterior Tibial Tendinopathy: The Inner Ankle Pain That Flattens Your Arch

What is posterior tibial tendinopathy?

The posterior tibial tendon runs behind the inner ankle bone (medial malleolus) and attaches to the navicular bone and the sole of the foot. It's the primary supporter of the medial arch during the push-off phase of running.

When this tendon is overloaded, it degenerates. In severe cases, it can rupture, leading to progressive arch collapse - a condition called adult-acquired flatfoot deformity. This makes early recognition important.

Symptoms

• Pain and swelling on the inner side of the ankle, just behind the ankle bone
• Worsening over the course of a run
• Difficulty or pain with single-leg heel raise (classic test)
• In advanced cases, the arch may visibly lower compared to the other foot

Who is at risk?

• Runners with flat feet or overpronation
• Those who have increased mileage rapidly
• Runners over 40 - the tendon becomes less resilient with age
• Women - this condition is more common in women

The key exercise: single-leg heel raise

The inability to perform a single-leg heel raise, or pain with doing so, is the defining clinical sign. This exercise is also the cornerstone of treatment.

Start: double-leg heel raise, slow tempo, 3 sets of 15.

Progress: single-leg heel raise, full range, 3 sets of 15.

Progress further: single-leg heel raise off a step (full eccentric range), 4 sets of 12.

This is the primary driver of tendon adaptation.

Additional exercises

Arch strengthening - short foot exercise

Scrunch the arch without curling the toes. 3 × 10, held 5 seconds. Activates tibialis posterior directly.

Calf complex strengthening

Both gastrocnemius and soleus are critical to reduce load on the posterior tibial tendon. 3 sets of 15 each.

Hip and glute work

Reduces overpronation mechanics. Clamshells, hip abduction, single-leg bridges.

Footwear and orthotics

A motion control shoe or a semi-rigid orthotic with medial arch support dramatically reduces tendon load during recovery. This is one of the few running injuries where footwear intervention has strong evidence.

Running during recovery

Running is possible at reduced volume if pain is manageable (< 3/10). Avoid prolonged runs and high-speed work. Use supportive footwear.

Timeline

8–12 weeks for mild to moderate cases. Severe or long-standing cases - especially those with any arch change - should be assessed by a physiotherapist or podiatrist promptly.