Several studies have detailed the effect that rapid weight cuts can have on athletic performance, which are common in mixed martial arts (MMA) and to a lesser extent boxing.
Due to the many injuries and even deaths linked to these practices, athletic commissions often hope to persuade athletes to avoid rapid weight cutting.
A study published in the European Journal of Sports Science, titled "Rapid weight gain predicts fight success in mixed martial arts - evidence from 1,400 weigh-ins," boasts that it is the largest real-world sample to date studying the issue.
The authors reviewed 1,400 weigh-ins from 21 MMA promotions regulated in California.
“We aimed to analyze whether rapid weight gain (RWG) between the official weigh-in and the time of the fight was associated with fight success in MMA. A total of 700 professional MMA fights involving 1,400 weigh-ins from 21 MMA promotions regulated by the California State Athletic Commission were analyzed. The odds ratios (OR) with 95% confidence intervals (95%CI) were calculated.
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The highest mean %RWG was found for the flyweight, bantamweight, featherweight, and lightweight divisions.
The %RWG significantly predicted the fight outcome (ß=0.044; OR=1.045; 95%CI=1.014-1.078; p=0.005) so that for each 1% of additional RWG, the chance of winning increased by 4.5%.
With the largest sample to date and in a ‘real-world’ scenario, the present results suggest that the magnitude of RWG is linked to the chance of winning in MMA combats.
Episode #15 - Weight Cutting & Performance in MMA with Dr. Oliver Barley
This data surely does add to the debate that serious weight cuts can be detrimental to athletes.
However, it does give credence to the idea that in an even matchup of skills, the good big man can beat a good small man.
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It’s why the study suggests, commissions may want to consider regulating how much weight athletes are allowed to cut to make division limits.
A strategy that is used by ONE Championship.
In an effort to curb extreme weight cutting, the California commission tracks how much weight fighters are gaining between weigh-ins and fight night with athletes being flagged if they gain more than 10 percent of their body weight, which could lead to a suggestion to potentially consider a change in divisions.
A total of 15 fighters competing at UFC 311 broke that 10 percent threshold.
On Tuesday, the California State Athletic Commission shared the fight night weights from the athletes competing at UFC 311 with MMA Fighting.
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Renato Moicano may have accepted a title fight at UFC 311 on just 24 hours’ notice, but he actually ended up weighing more than lightweight champion Islam Makhachev by the time they set foot in the octagon to go to battle.
Moicano hit the scale on Friday at 155 pounds to make championship weight but then he gained a whopping 26.8 pounds by fight night to weigh 181.8 pounds.
Here's a breakdown of the rapid weight gain observed at UFC 311:
| Fighter | Weigh-in Weight (lbs) | Fight Night Weight (lbs) | Weight Gain (lbs) | Weight Gain (%) |
|---|---|---|---|---|
| Renato Moicano | 155 | 181.8 | 26.8 | 17.3 |
| Other Fighters | Various | Various | Various | >10% (for 14 others) |