If you are reading this article sitting at a computer, you are sitting on the biggest muscles in your body. That is right. Gluteus maximus (to be specific) are the biggest and the most powerful muscles in the human body, and we got it as a prize for our ability to walk two-legged. Not playing an important role in walking as in a movement, Gluteus maximus take over the other muscles in straightening the pelvis to vertical when it comes to a strenuous work, as lifting heavy weight from a ground or a running up a hill.