Overview

This plan is a structured, progressive rehabilitation programme for achilles tendon pain built around loaded tendon work — the most evidence-based approach to achilles rehabilitation. It is designed to restore strength, load tolerance, and function across three distinct stages.

Tendons respond slowly to loading and require patience and consistency to rehabilitate properly. Rushing the process is one of the most common reasons achilles problems become chronic. Follow the structure, respect the progressions, and give your tendon the time it needs.

The three stages

Stage 1 — Isometric loading
Sustained, static contractions to reduce tendon pain and begin loading without aggravating movement through range. Isometric work provides significant pain relief in irritable tendons and builds the foundation required to progress. Do not rush this stage — it is doing more than it looks like.

Stage 2 — Isotonic loading
Slow, heavy, controlled loading through range. This is the primary stimulus for tendon adaptation and where the most meaningful structural change occurs. Tempo and load are everything — the work must be slow and deliberate to drive the adaptation the tendon needs.

Stage 3 — Energy storage and functional loading
More dynamic, sport-specific loading that prepares the tendon for the demands of running and triathlon. This stage bridges the gap between rehabilitation and full performance and should only be approached once Stage 2 is well tolerated and symptoms are consistently low.

When to progress — and when not to

Only progress from one stage to the next when symptoms are settled and your tendon is tolerating the current stage without reaction. Do not progress if symptoms are worsening during the strength work — pain above a 4 out of 10 is a signal to reduce load, not push through. Do not progress if symptoms are worsening in the 24 hours after a session. Symptoms should be the same or better during and after loading. Any consistent worsening is a signal to pause and reassess.

Day on, day off

Tendons adapt in the recovery period after a session, not during it. Load one day, rest the next. Consecutive days of tendon loading is one of the most reliable ways to drive a flare-up. The rest days are not optional — they are where the adaptation happens.

Scheduling around running

Rehabilitation sessions and running sessions should not fall on the same day where possible. Running is itself tendon loading. Alternate the two — if you run Monday, Wednesday, and Friday, schedule tendon loading on Tuesday and Thursday. If symptoms flare after a run, treat that as a loaded day and adjust accordingly.

Health disclaimer

This plan is for informational purposes only and does not constitute medical advice. Achilles tendon conditions vary significantly — consult a qualified physiotherapist or sports medicine practitioner before beginning. Do not use this plan if you suspect a tendon rupture, are post-surgical, or have been advised to rest completely. If symptoms significantly worsen or you experience acute pain or a sudden snap, stop immediately and seek urgent medical attention. The Tri Project accepts no liability for injury or adverse outcomes. You engage with this programme at your own risk.

A final note

Achilles rehabilitation rewards consistency and punishes impatience. Follow the plan, monitor your symptoms honestly, and reach out to the practitioner team if you are unsure at any point.