Posterior Tibial Pain in Runners

If you're feeling pain along the inside of your ankle or into your arch — especially during or after longer runs — you're likely dealing with posterior tibial tendon irritation. It's a common and often confusing injury because the pain can be vague at first, showing up in slightly different spots from day to day. You're right to pay attention to it, because this is one of those issues where early action makes a real difference.

What's Going On

Your posterior tibial tendon is the unsung hero of your foot's architecture. It runs behind the bony bump on the inside of your ankle and attaches into the bones of your midfoot, and its primary job is to hold up your arch during the stance phase of every stride. Think of it as a dynamic suspension cable — while the bones and ligaments provide the static structure of your arch, this tendon actively supports and controls it every time your foot hits the ground.

When you run, the posterior tibial tendon has to manage significant forces, especially during the push-off phase. If it's asked to do more than it's conditioned for — or if it's working overtime because of flat feet or excessive pronation — it becomes overloaded and irritated. Runners with lower arches are particularly susceptible because the tendon has to work harder to control arch collapse with every step.

This is an injury worth taking seriously. In its early stages, posterior tibial tendon dysfunction responds very well to strengthening exercises and training modifications. But if left unaddressed, it can progress to a point where the arch gradually flattens further, making the problem harder to reverse. The earlier you act, the simpler the solution.

Why This Happens

• Flat feet — a lower arch means the posterior tibial tendon has to work harder on every stride to provide the support that a higher arch gets for free from its bone structure
• Overpronation — excessive inward rolling of the foot during the landing phase stretches and loads the tendon repeatedly
• Weak arch muscles — the small intrinsic muscles of your foot help support the arch. When they're weak, more of the workload falls on the posterior tibial tendon.
• Sudden mileage increase — like all tendons, the posterior tibial tendon adapts slowly. A big jump in weekly mileage can overwhelm it before it has time to strengthen.
• Unsupportive footwear — shoes that don't match your foot type, particularly shoes with insufficient arch support for runners who need it
• Body weight — higher body weight increases the load on the tendon with every step, which matters more over the cumulative thousands of steps in a long run
• Age — tendon resilience naturally decreases over time, making this condition more common in runners over 40

How to Recognize It

• Pain along the inside of your ankle, behind the inner ankle bone, that may extend into the arch
• You'll notice it's worse during or after running, especially on longer efforts
• The pain tends to build gradually — it's not a sudden, sharp event
• In more pronounced cases, you might see swelling along the inner ankle
• Difficulty performing a single-leg calf raise on the affected side — you may notice your arch collapsing rather than holding firm
• Over time, you might observe that your arch appears flatter on the affected foot compared to the other side

When to Get Help

If you've been consistently doing arch strengthening exercises and modifying your training for 3 to 4 weeks without improvement, see a healthcare professional. This is particularly important if you notice your arch appears to be progressively flattening — that's a sign the tendon is losing its ability to support the foot's structure, and earlier intervention leads to significantly better outcomes.

Seek evaluation sooner if you notice:

• Pain during walking, not just running
• Visible asymmetry between your arches (one side noticeably flatter)
• Swelling that doesn't resolve with rest
• Inability to do a single-leg calf raise without the arch collapsing
• Pain that's steadily getting worse week over week despite modification

How to Adjust Your Training

Mild

You can keep running, but focus on adding arch strengthening into your daily routine: short foot exercises (gently drawing your arch upward without curling your toes), towel scrunches, and marble pickups all build the intrinsic foot muscles that support the posterior tibial tendon. Be conservative with mileage increases — now is not the time for big jumps in volume. Most runners at this stage can train through it comfortably with these additions.

Moderate

Dial back to easy running only and be disciplined about the pace. Single-leg calf raises are your best friend here — they directly strengthen the posterior tibial tendon and the calf muscles that support it. Continue with arch strengthening exercises daily. Consider a temporary supportive insole or arch support insert, which can reduce the tendon's workload while you build strength. You can still maintain solid fitness at easy effort; the goal is to give the tendon room to recover while progressively building its capacity.

Severe

This needs professional evaluation. Posterior tibial dysfunction that's progressed to this point may need imaging to assess the tendon's condition, and you'll likely benefit from custom orthotics or a structured rehabilitation program. Be honest with yourself about where you are — getting the right help now is what prevents a months-long issue from becoming a years-long one. Many runners at this stage do well with a combination of targeted physical therapy, appropriate orthotic support, and a gradual return-to-running plan.

Staying Ahead of It

• Arch strengthening — short foot exercises, toe yoga, and towel scrunches build the intrinsic foot muscles that share the workload with the posterior tibial tendon. A few minutes daily goes a long way.
• Calf strengthening — single-leg calf raises directly support the posterior tibial tendon because the calf and the posterior tibial tendon work as a team during push-off. Strong calves mean less isolated strain on the tendon.
• Appropriate footwear — if you have flat feet or tend to overpronate, shoes with adequate arch support and stability features make a meaningful difference. Get fitted at a specialty running store if you're unsure.
• Gradual mileage increases — respect the 10% rule (no more than a 10% increase in weekly volume). Tendons adapt more slowly than muscles and cardiovascular fitness, so patience with progression protects them.
• Intrinsic foot exercises — barefoot balance work and toe spreading exercises strengthen the small muscles of the foot that act as your arch's first line of support. Even walking barefoot around the house contributes.

The Bottom Line

Posterior tibial pain is your foot telling you that its primary arch support is overworked. The good news is that early-stage posterior tibial issues respond really well to consistent strengthening and sensible training modifications. Don't wait for it to get worse — start the arch and calf work now, be smart about your mileage progression, and you'll build a more resilient foundation for all the miles ahead.