Cheeky_Musician...you have a right to be suspicious a bit. Hip motion is basically another way of interpreting the application of mass into the overall technique, such as a punch. Remember, that force is equal to mass * acceleration. Acceleration alone with a lack of mass will be faulty as well as vice verca. Using a hip-twitch to create speed may succeed, but using the hip will invalidate it's ability to contribute to mass. Using hip ALONE to add mass into a punch will only allow the upper body mass to be added into a punch, thus corrupting balance (the key to strength) as well as the total manipulation of the potential of power. Power generated from the slight thrust back leg of a Zen stance that triggers the hip into a forward motion while executing a reverse punch will result in the greatest amount of potential power achieved. That way, you use the Zen stance to both apply extra force, mass, and acceleration as well as preserve your balance while executing the punch, your hip is added into the punch, adding more mass and acceleration, and the punch is then supported by the maximum amount of mass and acceleration that your body can provide without having a corruped sense of balance. Try it. Get into a Zen stance, have your back knee slightly bent, thrust off your back heel or ball of your foot, straighten your back knee as you thrust slightly forward into your punch and you will feel your hip coordinate naturally with your punch. That is the idea of a hip influenced punch, and trust me, the japanese are damn good at it. And btw...if the hip is ever thrown with a punch, it's always thrown the same time as teh punch is executed...never before to create acceleration. Your arm only weighs 2.5 Kilos...maybe 5 at max. With correct body mass application (or many would call, hip motion), the mass can potentially be as high as 15 kilos, and the accerlation would also be increased. Shiro 1st Dan World Shito-ryu Karate-do Federation