The roundhouse kick is the bread and butter of Tae Kwon Do. It constantly requires refining, shaping, and improvement. As you face your target, you lift and pull your kicking leg straight forward, using that lift to help you rotate your standing foot as close to 180 degrees backward as possible. Your outer hip then takes over the job of holding your lift and opening your knee as high as possible. This knee stays in one place as the lower leg flicks out, again requiring immense power and stability in hip and core so that all your strength goes into the target without causing your own body to rebound and lose balance.