Achilles Tendinopathy: What Runners Need to Know

What is Achilles tendinopathy?

The Achilles tendon connects your calf muscles to your heel bone. When it's overloaded - too much, too fast, too often - the tendon starts to break down faster than it can repair itself. That's tendinopathy.

It's not an inflammation in the traditional sense, which is why anti-inflammatories rarely fix it long-term. The tissue itself changes structure, and that takes a specific approach to reverse.

Most runners feel it as a stiff, achy heel first thing in the morning, or a burning sensation during or after a run. It often warms up after a few minutes of running, which tricks people into thinking it's fine - and then they overdo it.

Why does it happen?

A few patterns show up consistently:

• Mileage jumps - increasing distance or intensity too quickly is the most common trigger
• Returning after a break - your cardiovascular fitness comes back faster than your tendons adapt
• Tight or weak calves - the tendon absorbs more load when the muscle above it can't do its job
• Hard surfaces and hills - both increase the mechanical demand significantly
• Training in minimal shoes - increases calf and tendon load, especially if the change is sudden

What makes it worse

Running through persistent Achilles pain usually prolongs recovery. The tendon responds poorly to repeated overload without adequate rest.

Stretching the Achilles aggressively in the acute phase is also counterproductive - heavy static stretching can add compressive load to an already irritated tendon.

How long does recovery take?

Most cases resolve in 8 to 12 weeks with the right approach. Insertional tendinopathy (pain right at the heel bone) tends to take longer than midportion tendinopathy (pain a few centimetres above the heel).

The tissue needs consistent loading - not rest alone - to remodel properly.

The exercises that actually work

1. Isometric calf hold

Stand on the edge of a step, rise up on both feet, then shift weight to the affected foot. Hold for 30–45 seconds. Repeat 4 times. Use this in the painful phase - isometrics reduce tendon pain quickly.

2. Eccentric heel drop

Rise up on both feet, then lower slowly on the affected foot alone over 3 seconds. 3 sets of 15 reps, twice daily. This is the most evidence-backed exercise for Achilles tendinopathy.

3. Heavy slow resistance calf raise

Full range, slow tempo (3 seconds up, 3 seconds down). Add load progressively - a backpack with books works. 4 sets of 6 reps. This rebuilds tendon capacity long-term.

4. Single-leg balance

Stand on the affected foot, eyes open, then progress to eyes closed. 3 × 30 seconds. Trains the proprioceptive control that reduces tendon stress during running.

When can I run again?

You can start a return-to-run protocol when:

• Morning stiffness has gone or is minimal
• You can complete 20 heel raises on one leg with no more than 3/10 pain
• Walking for 30 minutes doesn't provoke symptoms

Start with run-walk intervals on flat ground. Avoid hills and speed work until you're back to full volume without symptoms.

One thing most runners miss

Loading the tendon - not resting it - is what drives recovery. Complete rest makes the tendon weaker. The goal is to find the right dose of load: enough to stimulate adaptation, not so much that it flares up. That balance is the whole game.