Achilles Tendonitis: Everything You Need to Know (No Medical Jargon)

Pain in the back of your ankle. Stiffness when you get out of bed. A dull ache that flares up when you run, climb stairs, or even walk too far. If this sounds familiar, you're likely dealing with Achilles tendonitis — one of the most common tendon problems in the world.

The good news: it responds extremely well to the right treatment. The frustrating news: most people are told to do exactly the wrong thing. This post gives you a clear, honest foundation — what Achilles tendonitis actually is, why it happens, and what to do about it.

What Is Achilles Tendonitis?

The Achilles tendon is the thickest and strongest tendon in your body. It connects your calf muscles (the gastrocnemius and soleus) to your heel bone (the calcaneus) and is responsible for the pushing-down motion you use when walking, running, jumping, or standing on your toes.

Achilles tendonitis — more accurately called Achilles tendinopathy — is a condition where the tendon becomes painful and loses its normal ability to tolerate load. It's not simply 'inflamed' (though acute cases can involve some irritation) — it's a sign that the tendon's capacity has been exceeded and it hasn't had the right stimulus to recover.

There are two main types:

• Midportion Achilles tendinopathy: pain located 2–6 cm above the heel bone. The most common type, particularly in runners and active adults.
• Insertional Achilles tendinopathy: pain right at the heel where the tendon attaches to the bone. Slightly different in its management — especially regarding heel drop exercises.

"Around 65% of Achilles tendinopathy cases are not sports-related. Anyone can develop it — from dedicated marathon runners to people who simply walk to work."

Who Gets Achilles Tendonitis?

Despite the association with running, research tells us that around 65% of Achilles tendinopathy cases are not sports-related. Common risk factors include:

• A sudden increase in activity level — starting a running programme, returning from a break, adding hill running
• Poor footwear choices — flat, unsupported shoes or a sudden switch from cushioned to minimalist footwear
• Reduced calf muscle strength, which places greater demand on the tendon
• Age — tendons become less adaptable as we get older, particularly after 35–40
• Metabolic conditions — diabetes and high cholesterol are associated with higher tendinopathy risk

Symptoms: What Does Achilles Tendonitis Feel Like?

The hallmark symptoms are:

• Pain and stiffness along the back of the ankle, worst in the morning or after periods of rest
• Pain that warms up with activity — often feels better after 5–10 minutes of movement, then may worsen again with prolonged or intense loading
• Tenderness to touch along the tendon
• Possible visible thickening of the tendon
• A clicking or creaking sensation with movement

It's worth noting: Achilles tendinopathy pain is generally worse at the start of activity and after activity, with a temporary improvement in the middle. If pain is severe and constant, or associated with significant swelling after an acute event, it's worth being assessed to rule out a partial or full tear.

The Most Effective Treatments for Achilles Tendonitis

The current evidence is clear: progressive tendon loading is the gold standard first-line treatment. This means structured exercises — particularly slow, heavy heel raises — that progressively challenge the Achilles tendon to adapt and build capacity.

Supporting strategies include temporary activity modification, heel raises in footwear, addressing calf muscle strength, and reviewing footwear and training load.

Frequently Asked Questions

How long does Achilles tendonitis take to heal?

With a structured loading programme, most people see meaningful improvement within 6–12 weeks. Complete resolution of symptoms and full return to sport can take 3–6 months. Chronic cases may take longer, but the same principles apply.

Should I stretch my Achilles tendon?

Aggressive stretching of an irritated Achilles is generally not recommended, especially for insertional cases. Gentle range-of-motion work is usually fine, but the primary focus should be on progressive loading, not stretching.

Is Achilles tendonitis the same as a heel spur?

No. A heel spur is a bony growth at the heel and is sometimes seen alongside insertional Achilles tendinopathy, but it is not the cause of pain. Many people with heel spurs have no symptoms at all.

For a detailed guide on exactly how to treat Achilles tendinopathy — step by step — read the exercise-first approach that works. Or if you want to go straight to the specific loading protocol, the complete heel raise guide has everything you need.