The key to balance is, in part, the ability to overpower your mind. Your brain possesses what some researchers call “common drive.” It wants to activate and relax all muscles in synchrony, including the opposing ones. It’s probably why you find yourself swaying while trying to balance on one leg. When you start to teeter, your mind drives all the muscles to stiffen at the same time. The problem: This drive contains muscle oscillations, which cause you to sway again and continue the process.