• Gastrocnemius: the superficial, two-headed calf muscle. It crosses both the knee and ankle.
• Soleus: the deeper calf muscle. It crosses the ankle only.
• Together, their tendons join to form the Achilles tendon, which inserts into the back of the heel bone (calcaneus).

How they contribute to ankle pain

1. Tight calf muscles
   • Limit ankle dorsiflexion, meaning the ability to bring the foot upward.
   • This increases pull and load on the Achilles tendon and heel, particularly during walking, running, stairs, and squatting.
   • It may lead to posterior ankle or heel pain, Achilles tendinopathy, plantar fasciitis, or altered ankle mechanics.
2. Overuse or strain
   • Repeated sprinting, jumping, hill running, or sudden training increases can strain the gastrocnemius or soleus.
   • Pain may be felt in the calf but can extend toward the ankle through the Achilles tendon.
3. Achilles tendinopathy
   • Usually causes pain and stiffness at the back of the ankle, either 2-6 cm above the heel or directly at the tendon insertion on the heel.
   • Calf tightness and weakness can both contribute. The AAOS explanation of Achilles tendinitis notes that tight calf muscles increase stress on the tendon.
4. Weak calf muscles
   • Can reduce push-off strength and impair ankle control.
   • The foot and ankle may compensate with altered loading, contributing to pain elsewhere, including the Achilles tendon or the outer/inner ankle.

A useful clinical clue

• Pain worse when the knee is straight during a calf stretch suggests greater gastrocnemius involvement.
• Pain or restricted ankle dorsiflexion both with the knee straight and bent may indicate soleus tightness or a more generalized Achilles-calf complex restriction.