I hear having Big Muscler Fighters are more Easier to Defeat. Big Muscler Need lots of Oxygen and Blood to keep fresh and hence put a lot of pressure on our heart.

This fact is the very reason why lightweight fighters seem to have endless "cardio" in competition whereas heavyweight fighters typically run out of gas in a few rounds

The most important part of the body is the Core Muscler. But biceps are important too.

To be very clear, "lifting weights can help your game." However, it does not help an extraordinary amount. It must be done correctly in order for it to be effective too. If you lift for size and power, then you are in the wrong sport.

Then What is the Correct way?? -.-