Definition
The gastrocnemius is the large, prominent muscle on the back of your lower leg, forming a major part of your calf. It’s the one you see bulging when you flex your calf. This muscle is responsible for plantarflexion (pointing your toes) and knee flexion (bending your knee). It works with the soleus muscle to help you walk, run, and jump. Think of it as the engine that powers your calf movements.