The Calf Muscles

Calf strain

The calf muscles consist of the gastrocnemius and soleus muscles at the back of the lower leg.

Gastrocnemius muscle

The gastrocnemius muscle is the larger of the two calf muscles. It is a powerful muscle, important for going up onto your toes, especially running and jumping.

Gastrocnemius muscle

Origin and insertion

It originates from the bottom of the femur (thigh bone) above the knee joint and inserts via the achilles tendon into the back of the heel.

The gastrocnemius muscles has two ‘heads’. The medial (inside) head originates from the posterior surface of the medial femoral condyle. The lateral (outside) head originates from the posterior surface of the lateral femoral condyle.

Joint actions

When the gastrocnemius muscle contracts it plantar flexes the ankle (points the foot downwards). It also flexes the knee but only very weakly. The hamstring muscles are the main knee flexors.

Innervation

  • Tibial nerve

Soleus muscle

The soleus muscle is the smaller calf muscle located lower down and deeper at the back of lower leg. It is also an important muscle for running and jumping activities.

Origin and insertion

The soleus originates below the knee at the top of the fibula and the upper part of the tibia (shin bone). It also inserts into the back of the heel via the Achilles tendon.

Joint actions

When the soleus contracts it plantar flexes the ankle joint (points the foot downwards).

Innervation

  • Tibial nerve

Calf muscle injuries

The following injuries cause pain in the calf muscles:

Calf strain

A calf strain or torn calf muscle is a tear of either the gastrocnemius or soleus. Most common is a tear of the larger gastrocnemius muscle where the muscle connects to the tendon.

Compartment syndrome

A compartment syndrome occurs when pressure within the muscle becomes too great. Symptoms consist of pain in the calf muscle area which becomes progressively worse with exercise.

Calf muscle exercises

The following are examples of calf muscle strengthening exercises.

Calf raise

Calf raise

Stand on a step with your heels off the back. Or lean forwards against a wall with both feet 50cm or so back from the wall.

Raise up and down to work the calf muscles. Do single leg repetitions to increase difficulty.

Seated calf raise

To strengthen the soleus muscle you need to bend your knee. The seated calf raise is great for isolating the soleus. Or as an alternative do standing calf raises as above, but with your knee bent.

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