What two muscles primarily make up the calf of the leg?

The calf of the leg is primarily composed of two muscles: the gastrocnemius and the soleus. The gastrocnemius is the larger and more visible muscle that has two heads, located at the back of the lower leg. It is involved in knee flexion and plantar flexion of the foot. The soleus lies underneath the gastrocnemius and plays a crucial role in maintaining posture and stability as it primarily functions during activities such as walking and standing, contributing to plantar flexion.

This combination of the gastrocnemius and soleus is what forms the majority of the muscle mass in the calf region, allowing for powerful movements like pushing off the ground and running. Other options listed do not accurately describe the primary muscles of the calf. For example, the Achilles tendon, while it connects these muscles to the heel, is not a muscle itself and thus not part of a muscle composition answer. The quadriceps and hamstring are muscles associated with the thigh, whereas peroneus and tibialis refer to muscles involved with the lower leg but do not constitute the calf muscles.