Posterior tibial tendinopathy (the modern term has largely replaced "tendinitis" because the pathology is degenerative rather than inflammatory) is one of the longer-tail return-to-run problems in distance running. This guide is built as a numbered protocol. Each phase has entry criteria and exit criteria. Move forward only when both are met. The structure is deliberately app-onboarding-flow simple, because the most common return-to-run failure is doing the right things in the wrong order.
Work through it once end to end before you start. Note where you are now. Resist the temptation to skip phases. The medial arch and posterior tibial tendon have specific recovery timelines, and shortcutting them is the single most common reason runners re-injure within 6 to 8 weeks of return.
Step 1: Confirm you are ready to start the return
The return-to-run window opens when specific symptoms have settled. Not before.
The entry criteria
- Pain-free walking in normal supportive footwear for 10 consecutive days.
- Pain-free single-leg calf raise on the affected leg, 10 controlled reps.
- No medial ankle swelling at the end of a normal walking day.
- No nocturnal pain or morning stiffness lasting more than 5 minutes.
- Absence of arch collapse on single-leg stance (compare to the unaffected side).
If any criterion is unmet, the return-to-run start is premature. Of these, the single-leg calf raise is the most predictive. A failed calf raise means the tendon cannot yet tolerate the load of a single foot bearing the body, which is the minimum demand of every running step.
Why this matters
Posterior tibial tendon dysfunction has a staged progression in clinical literature (Johnson and Strom, 1989). Returning to running before the tendon has rebuilt capacity moves the runner backward through the stages. Patience here is not optional. It is the entire intervention.
Step 2: Build the strength foundation
The tendon needs progressive load to rebuild collagen capacity. Two to three sessions per week, throughout the return-to-run phase and beyond.
The core exercises
- Single-leg calf raises with knee straight. 3 sets of 12 to 15 reps. Progress to dumbbell weighted as tolerated.
- Single-leg calf raises with knee bent (targeting soleus). 3 sets of 12 to 15 reps.
- Heel raises on the edge of a step, with the foot inverted slightly. This loads the posterior tibial tendon specifically. 3 sets of 10 reps.
- Resisted foot inversion with a band. 3 sets of 15 reps.
- Single-leg balance on a stable then unstable surface, 30 to 60 seconds per side.
The full progression is available in the STRIDD exercise library. Load progresses every two weeks. The tempo should be slow (3 seconds up, 3 seconds down) for the calf raise variants.
The footwear addition
A supportive shoe with stability features and a slight motion-control structure is standard during the return phase. Avoid minimal or zero-drop shoes during the rebuild. Custom orthotics with medial arch support are sometimes added. Most chemist-bought arch support inserts are also adequate for early return.
Step 3: Phase 1 of running - walk-run reintroduction
This is week 1 and week 2 of the structured return. The aim is to expose the tendon to running load in small, recoverable doses.
The week-1 protocol
- Three sessions, spaced by at least one rest day. Day 1, Day 3, Day 5.
- Total session duration: 25 minutes.
- Ratio: 1 minute easy run, 2 minutes walk. Repeat 8 times. Walk-only warm-up and cool-down for the remaining time.
- Surface: soft. Treadmill (3 percent incline to soften impact), synthetic athletics track, packed mud path.
- Pain rule: pain during the session must not exceed 2 out of 10. Pain must return to baseline within 24 hours.
The week-2 protocol
If week 1 was tolerated cleanly, progress to 2 minutes run / 1 minute walk, repeated 8 times. Same surface. Same pain rules. If either pain threshold is breached during week 1, repeat week 1 rather than advancing.
Step 4: Phase 2 of running - continuous easy running
Weeks 3 to 5. Continuous running, easy pace.
Week 3
Three sessions of 20 minutes continuous easy running. Soft surfaces. Cadence focus: target 170 to 180 steps per minute, achieved by shortening stride. Strength sessions continue twice per week.
Week 4
Three sessions of 25 to 30 minutes continuous running. Add a fourth session at 20 minutes if week 3 was tolerated cleanly. One session can move to a flat road surface if pain remains absent.
Week 5
Three to four sessions, 30 to 40 minutes. One can include 4 to 6 minutes of slightly elevated pace (faster than easy, slower than tempo). All other sessions remain easy.
Step 5: Phase 3 of running - volume rebuild
Weeks 6 to 9. Volume returns toward pre-injury levels. Variety returns.
The progression rule
Increase weekly volume by no more than 10 percent from the previous week. The 10 percent rule, while imperfect, gives the tendon time to adapt. Acute jumps above this threshold are the leading cause of re-injury in this window.
Re-introducing structured workouts
Week 7: one short tempo workout, 4 x 5 minutes at controlled-tempo pace with 2 minutes easy between. Week 8: add a single hill repeat session (4 to 6 repeats of 90 to 120 seconds on a moderate grade). Week 9: combine a longer tempo (15 to 20 minutes continuous) with one hill session in the same week.
Re-introducing race shoes
The motion-control or stability shoe stays in the rotation for daily runs throughout this phase. Race shoes (lighter, less supportive) can be tested for short tempo segments in week 9 if pain remains absent in the stability shoe across the full training week.
Step 6: Phase 4 - specificity and goal-race readiness
Weeks 10 onwards. The training looks like normal training for your goal race.
The specificity rule
Your training now matches the demands of your goal race: long runs at race effort, race-pace workouts, race-day fuelling and shoe rehearsal. Build the plan in the STRIDD plan generator with your current weekly hours and target finish time. Do not match a pre-injury plan; match a current-fitness plan.
The maintenance rule
Two strength sessions per week continue indefinitely. Posterior tibial tendinopathy recurs in runners who stop strength training once they feel better. The maintenance work is the reason the recurrence does not happen.
Step 7: Monitor the warning signs
Across all phases, watch for these flags. Each is a signal to deload one week or step back one phase.
Daily monitoring
- Morning stiffness in the medial ankle lasting more than 5 minutes.
- Medial ankle swelling at the end of a normal day.
- Pain during the single-leg calf raise.
- Visible arch collapse on single-leg stance.
- Pain that starts within the first 10 minutes of a run, rather than after 20 plus.
Any one of these means hold the current week. Two or more means step back one phase. None of these means continue the progression as planned.
What to do this week
If you have walked through the seven steps above, identify your current phase. Restart at the phase entry criteria, not the phase you wish you were in. Read the STRIDD recovery guide for the broader framework. Read the STRIDD injuries hub for the differential diagnosis of medial ankle pain. Build the strength routine in the Running Lab's linked exercise resources, and use the plan generator to translate your phase into a runnable week.
Most return-to-run programmes for posterior tibial tendinopathy run 10 to 16 weeks from start to full training. The structure is patient and the structure is the intervention. Trust it. Skip nothing. The tendon does not negotiate.