The calf comprises of three muscles: the two heads of the gastrocnemius and the soleus. The gastrocnemius heads arise from the posterior portions of the femoral condyles (back of the thigh bone). The soleus arises from the posterior aspect of the tibia and fibula (the two bones in the lower leg).

The gastrocnemius is a muscle that crosses three joints: the knee, the ankle, and the sub-talar joint (major joint in the foot). The functioning of these joints and influence of other muscles on these joints has a significant effect on the tension that occurs within the calf. As an example tight hamstrings impact the functioning of the ankle joint, the sub-talar joint, and increase tension in the calf. The soleus muscle does not cross the knee and is a biarticular muscle (affects the movement of two joints).

Calf strain symptoms

Calf strain often begins with mild pain after exercise or running that gradually worsens.

Other calf strain symptoms include:

Recurring localised pain, sometimes severe, along the calf during or a few hours after running.

Morning tenderness in the calf.

Sluggishness in your leg.

Pain when standing on tip toe.

Mild or severe swelling.

Stiffness that generally diminishes as the tendon warms up with use.