[ANTSAN]

In adition to the above, there is only so much power you can generate by moving your arms. Aditional power comes from the hips keep your knees slightly bent and twist the hips in the same direction as the punching arm also push off the feet. To practise twist the hips as far as possible, you know your doing this when your chin starts touching your shoulder. Finally remember the punch isn't over until the arm is fully extended.