Keith Kizer: fighters who add more weight don't have an advantage

You got a really smart mouth for a guy who can't do math.

 

Heres another study found on PubMed of 142 boxers ranked by the IBF over 71 title fights as opposed to "regional" mma fighters/boxers not ranked by a known governing body.
https://pubmed.ncbi.nlm.nih.gov/27564844/

So among 142 ranked boxers competing at the championship level they found that both weight gain and weight discrepancy did not affect match outcomes, corroborating Kizer's results. They also observed a higher loss rate among boxers who gained more weight, though not to a statistically significant degree.

Here is another study looking at 83 elite youth olympic boxers from 12 European countries competing at the European Championships.
https://pubmed.ncbi.nlm.nih.gov/29182408/

They found that rapid weight loss "did not translate into competitive success" and that "boxing experience" is what was most significantly related to successful outcomes, not weight cutting.

Backing that up further is another study looking at 100 "elite boxers participating in the Australian national championships" that found no link between weight cutting and weight gain to winning or losing.
https://pubmed.ncbi.nlm.nih.gov/27834565/

So from the championship amateur boxing level to the championship professional boxing level weight rehydration was not found to affect the outcome.

 

76% of muscle is water and muscle is the main reservoir of water in the human body. Really thin boxers like Hamzah Sheeraz have a much more difficult weight cut because they have much less muscle to potentially store any extra water in. When they cut a lot of weight that water has to come from somewhere and when its not coming from muscle its going to have to come from somewhere else, like for example the brain. An example of a really thin boxer attempting to rehydrate a significant increase in weight was Diego Corrales against Floyd Mayweather. The weight cut left Corrales in a very weakened state and probably caused greatly diminished punch resistance, reaction time, and energy levels. Corrales rehydrated 16 pounds. Mayweather only rehydrated 6 pounds and looked like the much stronger and much fresher man despite Corrales rehydrating up two more weight classes.

https://www.ringtv.com/616484-floyd-mayweather-diego-corrales-pretty-boy-perfection-20-years-later/

 

To try to answer your question first tell me where are you getting that Sheeraz is 6'4? BoxRec and many other sources have him listed as only 6'3. For perspective Kingsley Ikeke was a 6'4 middleweight with a 79" reach who was very thin and not known for being a big weight cutter and BoxRec and other sources say that Sheeraz is only 6'3 with a 75" reach. So already Sheeraz is not as big as Ikeke, who was able to make the middleweight limit without being known to cut a lot of weight. In general very thin boxers don't tend to be the big weight cutters because they don't have a lot of places that they can store a lot of extra water.

 

The same day weigh in boxers can still be expected to rehydrate up to 5 pounds easily (or more if they have more muscle since muscle will store extra water) without severely impacting performance. The day before weigh in boxers can be said to be big weight cutters if they are rehydrating 15-20 pounds and on the extreme end of that they will have to potentially sacrifice some diminished punch resistance, reaction time, and energy levels doing so. So for the same day weigh in boxers vs the day before weigh in boxers anywhere from a 10 to 15 pound weight discrepancy can be expected and on the extreme end of that some negative impacts that come with cutting an extreme amount of weight can be expected. Now before we go further I think its useful to highlight a couple of fights like that just as a reminder. There was a 10 pound weight discrepancy for Floyd Mayweather vs Diego Corrales. There was a 17 pound weight discrepancy for Manny Pacquiao vs Antonio Margarito.

With that said the kind of weight also matters. When a boxer cuts a lot of weight it often doesn't mean that he's a naturally bigger man that has a naturally bigger frame or more bone density. It often just means that he just has more muscle to store more water. Its important to distinguish that it doesn't mean they are bigger in general but just bigger in this one specific aspect only.

The data tells us that weight gain and weight discrepancy does not affect the outcomes of fights and many fights will also back that up anecdotally. I think the only thing we can know for sure is that day before weigh in boxers will usually tend to have more muscle. But I think its highly questionable if having more muscle is actually better for boxing (for MMA and Wrestling, maybe) especially if it has to potentially come with a negative impact to punch resistance, reaction time, and energy levels. So instead of just saying that day before before weigh in boxers have an advantage over same day weigh in boxers because they weigh more, remember that doesn't mean they have a bigger frame or have bigger bones, that extreme weight cutting doesn't also have drawbacks, or that skill level isn't probably still the most important factor of all. I think instead of just looking at it one way it should just be looked at on a case by case basis. And if you do that I think you do gradually circle back and agree with Kizer's results and other data that came to similar results that generally a heavier fighter will win about 50% of the time and a lighter fighter will also win about 50% of the time.

 

4 separate studies including Kizer's informal study all came to the same conclusion independently without any collusion that weight difference did not affect fight outcomes. How do you explain all of these separate studies all coming to the same exact conclusion? They all looked at boxers ranked by a governing body competing at the championship level whereas your study came from looking at boxers competing at the regional level which is the term thats used to describe guys that compete in regional golden gloves tournaments or toughman style competitions. Any further useful information about them is left vague or purposely omitted. To your point about Corrales, you leave out him looking totally shot against Clottey and coming into the fight off of a back to back losing streak one being by a devastating knockout after having many career shortening wars. On the flip side to that I could also bring up Marcos Maidana rehydrating 19 pounds compared to Floyd Mayweather rehydrating only 2 pounds and still losing to him 2x. And there are many examples like that. The point is that just as we see in the data weight difference overall doesn't show to affect the outcome of fights either way and just like the data predicts we can also see that play out all the time in the real world when we tune in and watch the fights.

Its questionable to what extent more muscle actually helps in boxing. Maybe it does in MMA or Wrestling but its an inconclusive stance to take to say its something that influences who is going to win a fight in boxing. How often does a less muscular fighter beat a more muscular fighter? A less muscular fighter can have the bigger frame or have the bigger bones and be functionally just as strong or stronger. A more muscular fighter doesn't gain any advantage to chin and its not known if putting on more muscle even helps you hit harder. Putting on too much muscle might even do more bad than good. For something thats supposed to influence the outcome of fights its difficult to prove what the actual benefit is at all.

The most I think you can say is that being the fighter that weighs more is one factor out of very many factors that might help. And that in many cases it also might not help. You couldn't say it would help conclusively in every case or use it as a universal rule that can be applied to all fights. You can only suggest it inconclusively on a case by case basis but not as a useful predictor of fight outcomes overall. Which why I say that after while it all eventually circles back around to Kizer's results and it all just more or less balances out to a 50/50 split either way.