Gastrocnemius

The gastrocnemius muscle, also known as the calf’s “twin muscle,” is the most prominent muscle of the lower leg and largely defines the shape of the calf. It consists of two strong muscle heads that originate above the knee joint and merge into the Achilles tendon. The gastrocnemius flexes the knee while simultaneously extending the ankle joint, making it especially important for running, jumping, and pushing off the toes.