The One Inch Punch is an ancient martial arts move of kung-fu. In this popular mechanics article the neuroscience of the punch is explored.
While the biomechanics behind the powerful blow certainly aren't trivial, the punch owes far more to brain structure than to raw strength...
By the time the one-inch punch has made contact with its target, Lee has combined the power of some of the biggest muscles in his body into a tiny area of force. But while the one-inch punch is built upon the explosive power of multiple muscles, Rose insists that Bruce Lee's muscles are actually not the most important engine behind the blow.
"Muscle fibers do not dictate coordination," Rose says, "and coordination and timing are essential factors behind movements like this one-inch punch."
(Score: 1, Informative) by Anonymous Coward on Sunday June 01 2014, @11:05AM
For straight punches, such as this one, the wrist is twisted palm down at the and of the punch to prevent injury to the elbow ligaments.
It is not done to add more force or impulse to the blow; if a fighter tells you otherwise it is because he is parroting what somebody else told him.