The punch is powerful but takes a little time to arrive at the target.

This is known as a cross punch. This punch is normally made with the dominant hand of the boxer at the same time the opponent leads a punch with the opposite hand, it is known as the cross punch as it crosses over the leading hand, and is a powerful punch that takes little time to arrive at the target. 

You would modify how often you work out in reps and sets and also modify calorie intake