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 LeeA powerful athlete is not a strong athlete, but one who can exert his strength quickly. Since power equals force times speed, if the athlete learns to make faster movements he increases his power, even though the contractile pulling strength of his muscles remains unchanged. Thus, a smaller man who can swing faster may hit as hard or as far as the heavier man who swings slowly.
Bruce LeeLet the spirit out - Discard all thoughts of reward, all hopes of praise and fears of blame, all awareness of one's bodily self. And, finally closing the avenues of sense perception, let the spirit out, as it will.
Bruce LeeThe ideal is unnatural naturalness, or natural unnaturalness. I mean it is a combination of both. I mean here is natural instinct and here is control. You are to combine the two in harmony. Not if you have one to the extreme, you'll be very unscientific. If you have another to the extreme, you become, all of a sudden, a mechanical man No longer a human being. It is a successful combination of both. That way it is a process of continuing growth.
Bruce Lee