Punching Power

[IronFist]

Here's a Little test for you
Stand up straight feet shoulder width apart
take and raise your right or left arm to shoulder height in front of yourself
have someone push the Raised arm down try to resist

now take your right or left arm which ever you used, and take the other arm and place it on the opposite shoulder of the arm you raised palm resting on the shoulder
now raise the opposing arm to shoulder height and have somebody try to push it down try to resist, tell me where your power comes from?

You've just proved that your anterior deltoid (front shoulder muscle) is responsible for holding your arm up and resisting gravity (a force pressing downward in this case). When you punch the effort with which you must resist gravity is very minimal. Does your shoulder play a role in punching? Absolutely. Is it the most important muscle? No. Even if you increase your power in this position it likely wouldn't contribute much to a harder punch. When you punch you're resisting a force in front of you, not a force pushing down from above.