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Effects of weight in punch resistance and power in boxing?

  1. Aug 1, 2017 #1
    I wasn't exactly sure which forum I should post this question in but I felt this was the most appropriate one. So if there is a more appropriate one, feel free to relocate it (whoever is responsible for that).

    I wanted strictly a scientific answer to this question. How does weight affect a boxer's punching power and punch resistance? In boxing, boxers are divided into weight divisions. Weight can be composed of many things such as muscles, fat, bone size and etc. However, boxing doesn't factor in all of those separate things when dividing boxers into weight divisions. It doesn't matter what a boxer's weight is composed of. In the end, all boxers are divided by weight divisions (irrespective of how much of the weight is fat, muscles or anything else).

    So what I wanted to know was how much of an affect does weight have on a boxer's punching power and punch resistance. Do things like muscle mass, fat quantity, skull size and etc. matter as much as purely weight or is boxing correct in making those factors less significant? Does it scientifically matter whether a boxer is mainly made of fat or muscles or anything else when it comes to punch resistance and power or are these factors irrelevant or not as irrelevant as PURELY weight?

    Does a heavier person have greater POTENTIAL for power than a lighter person, irrespective of how fat or muscular they are? Does a heavier person (without taking into account the amount of fat or muscles) also have higher punch resistance than lighter people? If the answer is yes to these questions, then why / how would that be?
  2. jcsd
  3. Aug 1, 2017 #2


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    I think that the place to start is to consider the momentum behind a punch. Suppose that two people throw the same punch with the same speed and form. The heavier person has more momentum behind the punch ( momentum = mass * velocity). On the receiving end, a person is knocked out by the acceleration of the head injuring the brain. A heavier person would absorb the momentum of a punch with less velocity. So his brain would not be bounced around as much as a lighter person's would.
  4. Aug 27, 2017 #3
    Proper punching technique should be factored in too. A smaller person with proper form from years of training can, in theory, hit harder than someone who is bigger but doesn't know how to throw his fists properly.

    Case in point Anderson Silva traditionally fights at 188 lbs yet went up a weight class to 205 lbs and knocked out three opponents in that division.

    In fact two of the fighters he KO'ed, Forest Griffin and Stephen Bonner fought each other in a slugfest. They punched each other for three rounds(15 mins) as hard as they could and neither could knock the other out. Silva took them both out in the first round with a single blow, despite being almost 20 lbs smaller.

    The Spider is known for picture perfect striking technique and accuracy. He is able to hit his foe in a precise location while in battle. And he is noted for maximizing power with no wasted motion; ie no big build up; winding his arms, etc etc.

    That being said if all things are equal than the bigger person would hit harder by utilizing the same technique just because he has more mass and presumably strength to back up his form too.
  5. Aug 28, 2017 #4
    How about punch resistance? What ways does having more weight help with absorbing punches better?
  6. Aug 28, 2017 #5


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    A larger person will gain a given amount of momentum with a lower velocity. That, and F=MA, means he will suffer lower accelerations and the jarring of the brain will be reduced.
  7. Sep 5, 2017 #6
    Thank you very much! Now it makes perfect sense!
  8. Sep 19, 2017 #7


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    Yes and in fact ring deaths and most serious injuries are in lightweights and lighter classes.
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