Which muscle is responsible for plantarflexion of the foot?

The gastrocnemius muscle is indeed primarily responsible for plantarflexion of the foot. It is one of the main muscles located in the calf region and plays a significant role in movements like walking, running, and jumping. When the gastrocnemius contracts, it pulls on the Achilles tendon, resulting in the foot pointing downward, which is the action known as plantarflexion.

This muscle not only assists in stabilizing the ankle but also contributes to knee flexion due to its dual attachment points—it originates from the femur and inserts into the calcaneus through the Achilles tendon. Thus, when discussing plantarflexion, the gastrocnemius is pivotal due to its size, strength, and function in lower limb mobility.