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 LeeFear comes from uncertainty; we can eliminate the fear within us when we know ourselves better. As the great Sun Tzu said: โWhen you know yourself and your opponent, you will win every time. When you know yourself but not your opponent, you will win one and lose one. However, when you do not know yourself or your opponent, you will be imperiled every time.
Bruce LeeAwareness is without choice, without demand, without anxiety; in that state of mind, there is perception.
Bruce LeeThe consciousness of self is the greatest hindrance to the proper execution of all physical action.
Bruce Lee