How to return to sport after an Achilles injury

Phase 1 begins when pain is present at rest or with minimal activity. No running. The focus is reducing tendon reactivity while maintaining some mechanical stimulus. Isometric calf holds (standing on a step, held for 30–45 seconds, repeated 4–5 times daily) load the tendon without the dynamic stress of isotonic movement. These are tolerable even in reactive tendons.

Phase 1 continues until resting pain is below 2/10 and the tendon does not react (pain spike the morning after) to isometric loading.

Seated calf raise (soleus focus) and standing calf raise (gastrocnemius focus), both with the tempo: 3 seconds concentric, 3 seconds hold at the top, 3 seconds eccentric. 3 sets of 15, twice daily. Load with bodyweight initially, progressed to added resistance (weighted rucksack or machine) every 2 weeks as strength improves.

Phase 2 continues until single-leg heel raise (no added load) reaches 15 repetitions pain-free.

The primary criterion for returning to running is a single-leg heel raise of 25 repetitions, pain-free, symmetric to the unaffected side. This tests the eccentric capacity of the calf-Achilles complex under the load it will experience during running.

Do not rush this phase. A tendon that cannot perform 25 single-leg calf raises is not ready for the eccentric demand of running. This is not a time-based criterion, it is a performance benchmark.

Begin with walk-run intervals on flat terrain. Session 1: 1 minute running, 2 minutes walking, repeated 6 times. Monitor tendon pain during the run (maximum 3/10), and critically, monitor the next morning (target: 0–2/10, no spike above 3/10). If the morning-after rule is met, progress to the next interval ratio at the following session.

Do not run on consecutive days in Phase 4. Give the tendon 48 hours between sessions to respond.

Continuous running begins when the walk-run intervals are pain-free at 10 minutes continuous. Volume increases by no more than 10% per week. Speed work and hills are the last components to return, these produce the highest peak Achilles load and are reintroduced only after sustained pain-free continuous running.

The role of soft tissue therapy throughout: manual work to the calf complex during all phases to maintain tissue quality and prevent the surrounding structures from overloading during the return.