The gastrocnemius is perhaps best known as the larger calf muscle which creates the diamond shape bulge in your legs. The type of exercise in the video revolves around the extension of your knee with your toes pointed in various directions, stretching your calf muscle while at the same time strengthening it. Many people have naturally large calf muscles while others perhaps need to work a little more at adding definition. However, the gastrocnemius is very important muscle in nearly every type of exercise you do. Even when you are lifting weights with your hands and arms, this still puts pressure on the core of your body through your legs and especially your calf muscles. You will certainly know you have been exercising even just after a few minutes!