The very powerful gastrocnemius muscles
The gastrocnemius muscles take full advantage of the lever created at the ankle joint. This is the same type of lever that a wheelbarrow uses. There is a fulcrum at the front (wheel/toes) and a load in the center (barrow/body through tibia), which creates force to lift a large amount of weight (you/gastrocnemius and the soleus muscle). The use of this type of lever makes gastrocnemius extremely powerful and well designed for walking, running, jumping, and many other activities.
What does the name gastrocnemius muscles mean?
The name Gastrocnemius comes from Greek. The Greek word “gaster” means “belly”.The word “kneme” means the leg. Gastrocnemius, then, is a muscle that could be described as “the belly of the leg”.
Where do the gastrocnemius muscles attach?
Gastrocnemius is the most superficial muscle in the posterior compartment of the leg. It lies on top of the soleus. It has two heads which originate in different locations, but which come together to insert at the same place.
The medial head originates on the medial epicondyle of the femur, while the lateral head originates on the lateral epicondyle of the femur.
The two heads come together to insert, along with the posterior end of the soleus, on the calcaneus via the Achilles tendon.
What actions do the gastrocnemius muscles do?
The primary function of the gastrocnemius is plantarflexion of the ankle. Additionally, because it crosses the knee joint, it can assist in flexion of the knee.
Poses where these muscles contract
Purvottanasana is a posture that requires us to do a strong plantarflexion (point) at the ankles in order to get the bottom of the feet to the floor.
In shalabasana we are typically pointing our toes and ankles in plantarflexion requiring us to use these muscles.
Poses where these muscles are lengthened
Downward facing dog is one of a number of postures that requires us to create or do dorsiflexion at the ankle. Dorsiflexion will generally stretch these muscles.