Hello, this is Jamie Glick, and I'm here to talk to you about the muscle structure of running. The function of the muscles in running is very important because running is a very complex series of movements that must take place in a coordinated effort. There are two main types of muscle in the body. There's smooth muscle and striated muscle. Smooth muscle is what runs your organs, your heart, your intestines and muscles that are considered involuntary. The skeletal muscle or the striated muscle are the muscles that you control yourself. So these are obviously the important ones that you are going to use when you are running. The striated muscle requires a series of very complex interactions on the cellular level. So the muscle fiber itself is controlled by a couple of proteins called actin and myosin and the actin and myosin come together and they interact to cause ATP which is the energy cell of the muscle to cause that muscle to contract and each muscle obviously has a different function and must contract in a different kind of way in order to propel your body down a track or down whatever course you are running.