anatomy/achilles-tendon·Tendon / ligament
Achilles tendon
Tendo calcaneus
The thickest and strongest tendon in the body. It connects the calf muscles to the heel and stores energy like a spring when running.
// Structure & location
The tendons of the gastrocnemius and soleus merge about halfway down the lower leg into the Achilles tendon. It runs behind the ankle and inserts on the heel bone. You can easily grip it above the heel as a firm cord.
// Function
It transmits the force of the calf to the heel and lifts it. In running and jumping it is stretched with every ground contact and returns the stored energy at push-off, much like a spring.
// For training & sport
- Pain in the tendon when running is common, especially after quick increases in mileage.
- Tendon problems are often treated with slow, heavy or lowering calf raises to make the tendon resilient again.
// Good to know
A rupture often happens during a sudden sprint start or jump. Many people report a pop, as if someone kicked them from behind. The name comes from the Greek hero Achilles, whose heel was his only vulnerable spot.
// Sources
last reviewed: 2026-11-14