Is the back of your ankle (Achilles tendon) sore and stiff in the morning — worse with running?
Achilles Tendinitis — the tendon is accumulating micro-damage from repetitive loading.
If the tendon above your heel is sore and stiff in the morning, eases a little with movement, then worsens during running or jumping, Achilles tendinitis is a likely diagnosis. Early treatment prevents progression to a chronic tear.
Quick Answer: The Achilles tendon is the body’s largest tendon, connecting the calf muscles to the heel bone. Repetitive running or jumping loads accumulate micro-damage in the tendon, leading to tendinopathy. Calf muscle tightness or weakness increases the load on the tendon. The key is restoring tendon capacity while reducing excessive load.
⚠️ Seek prompt evaluation if:
- Sudden “pop” sound in the Achilles area with immediate severe pain — possible tendon rupture, seek urgent care
- Severe ankle swelling preventing weight-bearing
Symptoms of Achilles Tendinitis
- Pain, swelling, and tenderness above the heel — The area is painful to touch and may appear swollen.
- Worse with the first steps after waking or resting — Eases somewhat once warmed up, then may worsen again with activity.
- Aggravated by running, stairs, and jumping — Symptoms build during or after activity.
- Thickening or a hard nodule in the tendon — The tendon may feel thick or have a palpable bump.
- Calf tightness alongside tendon pain — Stiffness or pulling in the calf is a common companion symptom.
Why Does It Happen?
The Achilles tendon is the largest and strongest tendon in the body, connecting the calf muscles (gastrocnemius and soleus) to the heel bone. It bears enormous loads during walking, running, and jumping.
Repeated overloading causes micro-damage to the tendon fibres and impairs the local blood supply. Calf inflexibility further increases tendon stress. Insufficient footwear cushioning and sudden spikes in training volume are key risk factors.
Pain = Alarm (sensitivity) × Load (stress)
- Load: Repeated running/jumping accumulates tendon overload
- Load: Calf inflexibility increases tendon tension
- Load: Sudden training increase, poor footwear cushioning
- Alarm: Chronic sensitisation amplifies pain around the tendon
Tendinitis vs Tendon Rupture
Tendinitis (Conservative Treatment)
- Pain but no rupture
- Swelling and tenderness, but still able to walk
- Worse with running and jumping
- Recovers with eccentric exercises and Circulation Therapy
Tendon Rupture (Emergency)
- A sudden “pop” with immediate loss of ankle strength
- Unable to walk, unable to rise on tiptoe
- Rapid, severe swelling
- Go to the emergency room immediately
Our Approach at Yonsei SM Pain Clinic
Achilles tendinitis requires both reducing tendon inflammation and building tendon strength.
- Phase 1: Calm (Circulation HD)
Reduce tendon inflammation and peritenon swelling. Myofascial release of the calf decreases Achilles tension and improves local circulation. - Phase 2: Activate (Circulation PT)
Eccentric calf exercises to rebuild tendon strength and load capacity. Ankle stability work and calf flexibility training. - Phase 3: Integrate
Correct gait and running mechanics through gait analysis. Progressive load management for safe return to activity.
Warm Compress Recommended: Applying a warm compress around the Achilles tendon (2–3 times daily, 15–20 min) improves blood flow and supports tendon recovery.
Self-Care Guide for Achilles Tendinitis
What to Avoid
- Running, jumping, and other high-impact exercise
- Flat, unsupportive footwear (flip-flops, slippers)
- Sudden spikes in training volume
- Deep massage directly on the tendon (may worsen inflammation)
What Helps
- Warm compress (2–3 times daily, 15–20 min)
- Heel cushion inserts inside shoes
- Low-impact exercise: swimming, cycling
- Eccentric calf stretching (under therapist guidance)
Frequently Asked Questions
How is Achilles tendinitis different from plantar fasciitis?
Achilles tendinitis causes pain at the back of the ankle above the heel, whereas plantar fasciitis causes pain at the bottom of the heel (where the fascia attaches to the heel bone). Both involve overload of connective tissue in the foot-ankle region, but the structures and treatment approaches differ somewhat. Plantar Fasciitis →
Can I run with Achilles tendinitis?
Continuing to run through significant Achilles pain risks worsening the tendon damage and potentially progressing to a rupture. A graduated return-to-running programme with load management is safer and more effective than pushing through pain.
Does Achilles tendinitis heal on its own?
Mild cases may improve with rest and reduced activity, but chronic Achilles tendinopathy often requires specific eccentric loading exercises to stimulate tendon remodelling. Without proper rehabilitation, symptoms frequently recur. Treatment Duration Q&A →
Why is warm compress recommended instead of ice?
Cold application constricts blood vessels, reducing circulation to an area that needs blood flow for tendon repair. Warm compresses promote local circulation and help the surrounding muscles relax, supporting recovery.
References
- Alfredson H et al. Heavy-load eccentric calf muscle training for the treatment of chronic Achilles tendinosis. Am J Sports Med. 1998;26(3):360-366.
- Beyer R et al. Eccentric training and heavy slow resistance training as treatment for Achilles tendinopathy: a randomised controlled trial. Am J Sports Med. 2015;43(7):1704-1711.
- Habets B et al. Effectiveness of exercise therapy in patients with non-insertional Achilles tendinopathy: a systematic review and meta-analysis. Br J Sports Med. 2017;52(22):1465-1472.
- de Vos RJ et al. Platelet-rich plasma injection for chronic Achilles tendinopathy: a randomized controlled trial. JAMA. 2010;303(2):144-149. PMID 20068208
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