The more relaxed the muscles are, the more energy can flow through the body. Using muscular tensions to try to 'do' the punch or attempting to use brute force to knock someone over will only work to opposite effect.
Bruce LeeThere is no mystery about my style. My movements are simple, direct and non-classical. The extraordinary part of it lies in its simplicity. Every movement in Jeet Kune-Do is being so of itself. There is nothing artificial about it. I always believe that the easy way is the right way.
Bruce LeeThe martial arts are ultimately self-knowledge. A punch or a kick is not to knock the hell out of the guy in front, but to knock the hell out of your ego, your fear, or your hang-ups.
Bruce Lee