Muscle of the Month: The Calf (Gastrocnemius & Soleus)

Part 1 of a Foot & Ankle Series

Looking back through the Muscle of the Month features from the past year, I noticed something surprising — we haven’t yet covered any of the foot and ankle muscles.

These muscles play a critical role in balance, gait, propulsion, and shock absorption. So over the next few months, I’ll be doing a series highlighting some key muscles of the lower leg and foot.

This month we’ll start with the calf muscles.

Upcoming features in this series will include:

• Tibialis Posterior

• Peroneus Longus

• Tibialis Anterior

Together, these muscles help support the arch, stabilize the ankle, and allow the foot to adapt efficiently during movement.

🎥 Watch the Video

👉 https://youtu.be/uJXjfZyUj24

In the video, I demonstrate several exercises to strengthen the calf muscles, as well as a stretch to help maintain healthy muscle length.

Anatomy: Gastrocnemius & Soleus

The calf (triceps surae) consists of two muscles: The gastrocnemius and soleus. These muscles work together to produce ankle plantar flexion (pointing the toes downward) and provide propulsion for walking, running, and jumping. The gastrocnemius is a two-joint muscle involved in fast, explosive movements, while the deeper, endurance-focused soleus stabilizes posture. Both muscles merge to form the Achilles tendon, which attaches to the heel bone and transmits force from the calf to the foot during walking, running, and jumping.

Gastrocnemius

The gastrocnemius is the large, superficial muscle that forms the visible bulk of the calf.

It has two heads:

• Medial head – originates from the posterior aspect of the medial femoral condyle

• Lateral head – originates from the posterior aspect of the lateral femoral condyle

Because the gastrocnemius originates above the knee joint and crosses both the knee and ankle, it has two primary actions:

• Plantarflexion of the ankle

• Flexion of the knee

  
  

The two heads join together and continue downward, merging with the soleus to form the Achilles tendon, which inserts onto the posterior surface of the calcaneus (heel bone).

Functionally, the gastrocnemius plays a major role in powerful movements such as running, jumping, and pushing off during gait. It also contributes to dynamic stabilization of the knee, particularly when absorbing forces during landing.

Soleus

The soleus lies deep to the gastrocnemius and is often referred to as the postural muscle of the calf.

It originates from:

• the posterior surface of the tibia (soleal line)

• the posterior surface of the fibula

Unlike the gastrocnemius, the soleus does not cross the knee joint — it crosses only the ankle joint.

Its primary action is:

• Plantarflexion of the ankle

  
  

Because of its anatomical position and fiber composition, the soleus is particularly important for postural control and endurance activities, working continuously during standing and walking.

Like the gastrocnemius, the soleus inserts into the Achilles tendon.

The Achilles Tendon

The gastrocnemius and soleus together form the Achilles tendon, the largest and strongest tendon in the body. This tendon transmits the powerful forces generated by the calf muscles to the foot, allowing us to:

• push off the ground during walking and running

• jump and propel the body upward

• absorb forces when landing

  
  

Because of the high loads it experiences, the Achilles tendon can be vulnerable to overuse injuries such as tendinopathy or tears, particularly when calf muscles are tight, shortened, or weak.

Function in Movement

Together, the calf muscles allow us to:

• Push off the ground during walking and running

• Propel the body upward during jumping

• Control landing forces

• Stabilize the ankle and foot

• Support efficient gait mechanics

  
  

The gastrocnemius also contributes to knee stabilization during dynamic activities, especially when absorbing forces during landing.

Why Calf Strength Matters

Strong calf muscles help provide:

✔ Efficient propulsion during gait ✔ Power for running and jumping ✔ Control during landing

✔ Improved ankle stability ✔ Better force transfer through the lower leg

Weakness in the calf complex can contribute to:

• Reduced push-off during walking

• Decreased athletic performance

• Increased stress on the Achilles tendon

• Ankle instability

Calf Tightness and Injury Risk

While the calf muscles are powerful, they are also commonly tight and shortened.

This can occur due to:

• High levels of athletic activity

• Repetitive running or jumping

• Prolonged sitting

• Wearing high-heeled shoes

When the calf muscles become shortened, they can increase strain on the Achilles tendon, potentially contributing to:

• Achilles tendinopathy

• Increased risk of tendon injury or tear

• Limited ankle dorsiflexion

• Altered walking and running mechanics

For this reason, maintaining both strength and flexibility in the calf muscles is important.

Strength and Stretching

Healthy calf function requires both:

✔ Strength to generate propulsion and support dynamic movement

✔ Flexibility to allow full ankle range of motion and reduce tendon strain

In the video, I demonstrate several strengthening exercises along with calf stretches to help maintain proper muscle length.

What’s Next?

What muscles would you like to see featured in upcoming Muscle of the Month posts? Send me a message — your ideas help guide future topics.

Supporting strong movement from the ground up,