Many martial artists wonder about the purpose of sine wave and how it is applied. I can personally attest to the benefits of studying and mastering sine wave as it was developed and taught by General Choi Hong Hi. Throughout my Taekwon-do career, I have always been relatively light -- averaging between 138 and 142 pounds -- and I had a hard time with power breaks. My light weight helps me jump for flying kicks, but it doesn't give me much weight to put into power breaks. However, since I started really studying sine wave and applying it to breaking, it became easy for me to handle power hand breaks. Note the wave created when I slightly drop my body mass, raise it again while the arms are relaxed and preparing for the strike, and drop my body mass as I aggressively increase the velocity of my knifehand strike. The combination of the wave and the gradual increase in velocity is the secret. The body mass passes the striking point at the same time the striking tool does and, at the moment of impact, the striking tool is moving as fast as possible.