Achilles Tendinitis Explained
In brief: Achilles tendinitis is irritation of the Achilles tendon, the strong cord connecting the calf to the heel bone. It causes pain and stiffness at the back of the heel or lower calf, classically worse in the morning and when starting to run. It is an overuse injury linked to sudden increases in training, tight calves and speed or hill work. Because the tendon is slow to heal, it responds best to patient, progressive loading rather than complete rest.
What is Achilles tendinitis?
The Achilles tendon is the thick cord that joins the calf muscles to the heel bone and transmits the force that pushes you off the ground with every stride. Achilles tendinitis, more accurately called tendinopathy when it becomes long-standing, is irritation and overload of this tendon. It is a common running injury because the tendon takes very high loads during running, particularly at faster paces and uphill.
What causes it in runners?
It typically follows a spike in training load, more mileage, faster sessions or added hill work, before the tendon has adapted. Tight or weak calf muscles increase the strain, as can a sudden change to lower-heeled or minimal shoes. Age and reduced tendon resilience over time also play a part.
Symptoms to recognise
The usual picture is pain and stiffness in the tendon at the back of the heel or just above it, often most noticeable on the first steps in the morning or at the start of a run. The area may be tender to touch and sometimes slightly thickened. The pain may ease as the tendon warms up, then return afterwards, which can tempt runners to keep going and prolong the problem.
Treatment and recovery
Because tendons are slow to heal and respond to load, the cornerstone of treatment is a graded calf-strengthening programme, particularly slow heel-drop exercises, rather than total rest. Reducing aggravating speed and hill work in the short term, alongside calf mobility, helps settle symptoms. Recovery is often measured in weeks to months and requires patience. A physiotherapist can structure the loading and confirm the diagnosis.
Achilles Tendinitis and your running kit at OD's
Shoes with appropriate cushioning and heel support, and avoiding an abrupt switch to a much lower heel drop, reduce strain on the tendon. At OD's Designer Clothing we stock premium running footwear from On, Saucony and Salomon, with fitting advice in our St Helens store. We offer next-day delivery and free click and collect.
Please note: This guide is general information for runners, not medical advice. If you have pain that is severe, persistent or getting worse, see a GP, physiotherapist or qualified sports clinician for diagnosis and treatment.