Achilles Tendinitis

How Achilles tendinitis develops

The Achilles tendon handles loads of several times body weight when you run and jump. When it is loaded more than it can adapt to, small areas of the tendon break down faster than they repair. Despite the name, there is little classic inflammation in long-standing cases. The tendon becomes thickened and disorganized, which is why many specialists prefer the term tendinopathy.

Types

Symptoms

• pain and stiffness along the tendon or at the back of the heel (heel pain), worse in the morning
• pain at the start of exercise that may ease as you warm up, then returns afterward and the next day
• tenderness when squeezing the tendon
• swelling or a thickened area
• creaking (crepitus) when moving the ankle, in some cases
• pain when rising on tiptoes or climbing stairs

Causes and risk factors

• Training errors: a sudden increase in distance, intensity or frequency, adding hills or speed work
• Weekend-warrior activity: sporadic intense sport in middle age
• Tight or weak calf muscles (see calf tightness)
• Footwear: worn-out or unsupportive shoes, switching suddenly to minimal shoes
• Foot mechanics: flat feet or high arches
• Age: tendons become stiffer and less able to repair from the 30s onward
• Medical factors: obesity, diabetes, high cholesterol, inflammatory arthritis, gout
• Medicines: fluoroquinolone antibiotics (ciprofloxacin, levofloxacin) raise the risk of tendinopathy and rupture, especially in people over 60 or taking steroids

Diagnosis

A doctor or physical therapist diagnoses it from your history and examination, feeling for tenderness, thickening and a gap, testing calf strength and ankle movement, and performing the Thompson test (squeezing the calf to see if the foot moves) to rule out a rupture. Ultrasound or MRI can confirm thickening, tears or bursitis, and an X-ray shows heel spurs in insertional cases. Pain under the heel rather than behind it is more likely plantar fasciitis.

Treatment

Load management

You usually do not need complete rest. Reduce or pause activities that aggravate pain, such as running and jumping, and switch to cycling or swimming. A useful guide: pain during and after exercise should stay at or below about 3 out of 10 and settle by the next morning.

Exercise therapy (the most effective treatment)

Progressive calf strengthening helps the tendon remodel. Common programs:

• Eccentric heel drops (Alfredson protocol): rise on both toes, then slowly lower on the affected leg, with the knee straight and then bent. Do 3 sets of 15 of each, twice a day, for 12 weeks. For insertional pain, lower only to floor level rather than below the step.
• Heavy slow resistance: slower, heavier calf raises 3 times a week, progressively loaded.
• Isometric holds: holding a calf raise for 30 to 45 seconds can ease pain early on.

Expect some discomfort. Improvement usually takes 6 to 12 weeks to show.

Other measures

• Heel lifts in both shoes reduce tendon strain, particularly for insertional pain.
• Supportive shoes with some heel height. Avoid going barefoot on hard floors.
• Ice for 15 minutes after activity for pain.
• Pain relievers: acetaminophen (paracetamol) or an NSAID for short periods. Follow the label dose.
• Weight loss if overweight.

When symptoms persist

• Shockwave therapy has reasonable evidence for stubborn cases.
• Injections: steroid injections are generally avoided because they can weaken the tendon and increase rupture risk. Platelet-rich plasma has not shown clear benefit.
• Surgery: for symptoms that persist after 6 months of good-quality rehabilitation. It removes damaged tissue or bone spurs, with recovery taking several months.

Complications

The main risk is Achilles tendon rupture, more likely with ongoing degeneration, steroid injections and fluoroquinolone use. Chronic pain can persist if loading is not progressed or if training is resumed too fast.

Recovery and return to sport

Most people improve within 3 months and recover fully within 6 months. Return to running gradually, starting with walk-run intervals on flat ground and increasing volume by about 10% a week, provided pain stays within the acceptable limit. Keep doing calf strengthening twice a week to prevent recurrence.

Prevention

• increase training gradually
• strengthen the calf muscles regularly
• warm up before exercise
• replace running shoes every 300 to 500 miles (500 to 800 km)
• vary training surfaces and avoid too much hill running

Frequently asked questions

What are the symptoms of Achilles tendinitis?

The main symptoms are pain and stiffness at the back of the heel or along the tendon, worst first thing in the morning and at the start of exercise. The tendon may be tender to squeeze, thickened or swollen, and it may hurt to rise on your toes.

How long does Achilles tendinitis take to heal?

Most people improve within 6 to 12 weeks of starting a structured exercise program and recover fully in 3 to 6 months. Long-standing or insertional cases can take longer. Returning to running too soon is the most common reason for setbacks.

Should I stretch Achilles tendinitis?

Gentle calf stretching is fine for mid-portion tendinitis, but strengthening exercises matter more. For insertional tendinitis, avoid deep stretches with the heel dropping below a step, because they compress the tendon against the heel bone and can worsen pain.

Can I walk with Achilles tendinitis?

Yes, walking is usually fine and helps keep the tendon healthy, as long as pain stays mild. Wear supportive shoes, consider heel lifts, and reduce long walks or hills if they worsen symptoms. Stop and seek care if you feel a sudden snap.

What is the difference between Achilles tendinitis and a rupture?

Tendinitis is a gradual overuse injury with pain and stiffness. A rupture is a sudden tear, often felt as a snap or a kick to the back of the ankle, followed by weakness pushing off and a gap in the tendon. A rupture needs urgent medical assessment.