Why Did Conor McGregor Gas Out?

Picture Taken By Ester Lin of MMAFighting

Picture Taken By Ester Lin of MMAFighting

After months of hype and trash talk, Conor McGregor finally achieved the unthinkable, crossing over into the boxing ring to face Floyd Mayweather Jr.  As expected by many people, Conor came out short against a defensive genius, the best boxer of our era; receiving a TKO loss on the way. While he was certainly outclassed, and out-composed, critics of Conor's performance say he simply did not have the gas tank or conditioning to last 12 rounds. As a fight fan, that's probably a sufficient description of what happened. As a performance coach, of course I'd like to dive deeper into the variables at play, and the reasons for his so called "poor conditioning". So here. we. go.

A quick disclaimer before I start this article: Of course I was not overseeing or anyway involved in Conor's fight camp so these are just my opinions and speculations based on my knowledge of martial arts, psychology and energy system development.

The Non-Culprits

Work Ethic


Work ethic is the first variable to rule out when analyzing Conor's conditioning. From the way he conducts himself and from interviews with other fighters, it's clear that Conor is a true martial artist and a work horse. A fighter trains hard once he has a fight lined up and a fight camp prepared, a true martial artist trains year round in order to sharpen the endless skillset that is required in the sport of MMA. However, this does not come without speed bumps.

It's been publicly stated by John Kavanagh (Conor's long time head coach) that somewhere between the Jose Aldo knockout (UFC 194) and the first Nate Diaz fight (UFC 196), Conor lost the work ethic and passion for training that got him into the position he is in today. At one point, Kavanagh said Conor would come to the gym late for training and the two would just walk past each other with no care in the world. When you knock out all of your opponents within the first 2 rounds of a fight, and you're so ahead of the striking game in terms of distance control and fight IQ, I would assume its difficult to find the motivation to improve your conditioning. Fair to say, getting tapped out in front of millions of people was a wake up call.

In preparation for the Diaz 2 fight (UFC 202), Conor worked more closely with his conditioning coach and exercise physiologist Dr. Julian Dalby, improving his anaerobic conditioning so he could push during hard exchanges and picking up road cycling as a means to improve general aerobic conditioning so he could recover faster in-between rounds. The results showed, Conor matched the conditioning of Diaz's and won a pretty clear-cut decision in my eyes.

After the first Diaz loss, I have no doubt in my mind Conor puts in the hard work and pushes himself to the limits during training camp.

You win or you learn
— John Kavanagh

Possible culprits

Conditioning Program


In contrary to what I discussed above, you can work your hardest but you won't achieve top level performance unless the prescription of conditioning and precision of energy system development is effective and evidence-based.

With more than 20 years experience in elite sports performance and who I assume to be the man behind the McGregor FAST Program, Dr. Julian Dalby (M.D) is more than qualified to prepare Conor for a boxing match. With the training system that revolves around the use of training principles such as the GREEN, ORANGE  and RED zone, which I assume corresponds to the aerobic, anaerobic and alactic stratification of training intensity, I will give their team the benefit of the doubt. Also overlooked by exercise physiologists at the UFC Performance Institute, there's a good chance Conor's preparation leading up to the fight was scientifically sound. 


Looking back, I'm sure Conor's team can point to things that they could have improved on, but the reason why I categorize this under "possible culprits" is because their conditioning preparation is most likely not the reason why Conor gassed out and lost this fight. With that said, I think he would have done much better given more time to prepare.

Body shots & body conditioning

One point I wanted to bring up that I haven't seen discussed much in the public is the impact of the body shots landed by Floyd in the early rounds. The general consensus amongst boxers, and muay thai kickboxers is that MMA fighters have relatively weaker body conditioning. Not neccesarily saying body shots aren't a valid technique in MMA, rather, it's not utilized as frequently since it's not part of the current meta; therefore MMA fighters are less conditioned to them.

Without the grappling aspect, boxers, kickboxers and muay thai practicioners are more well-versed in body shots as part of a wider striking arsenal. Body shots serve  to damage the body and conditioning of the opponent, and to drop the guard of the opponent to allow for shot selections to the exposed head. For the same reason, many striking specialists are more conditioned to body shots, have harder abdominal muscles and a higher pain tolerance.

According to FightMetric, Conor has not historically received a lot of body shots in his MMA career, with the exception of the Diaz 2 fight, where Diaz landed 50 body shots against Conor.

Taken from FightMetric.com

Taken from FightMetric.com

Luckily, Nate is no where near a power puncher and cannot be compared to the stabbing body shots Floyd intercepted Conor with during their boxing match. I really wonder if this played a role in Conor's deconditioning during the later rounds. I'm sure it was part of Floyd's plan to invest in the body early, as there seemed to be much less body shots in the latter rounds, where Floyd started to attack the head instead.

It should also be mentioned that Paulie has come out and said Conor does not take body shots well.


Whether Paulie is telling the truth or not, is still up for grabs. However, I'm inclined to believe him.

Main Culprits

Fight strategy and pacing

Taken from Sports Illustrated

Taken from Sports Illustrated

The biggest culprit in deciding Conor's fate is his inexperience inside the boxing ring, particularly his pacing strategy and his inability to sustain his desired power output.

“If you go for the knockout, you’ll lose the decision”
— Unknown

That's a quote I encountered a while back (I'm not sure who it was, Mike Tyson?, if you know, please shoot me a message) and the main takeaway from this quote is that, trying to hunt for the knockout, and not getting it, will often result in excessive energy expenditure, resulting in the fighter to gas out and eventually lose a decision. Once you overreach the lactate threshold for too long (commonly and comically referred to as "blowing your load"), it's very hard to recover from, even with the 1 minute rest periods between rounds. 

Conor is notorious for being a fast starter, and is hell-bent on getting that 1st or 2nd round knockout in many of his fights. More times than not, "Mystic Mac" does just that. However, boxing is a much more forgiving (or unforgiving depending on how you look at it) game than MMA. Limited to punches only, stricter clinching rules and larger gloves, it's much harder to score a knockout punch in boxing. Whereas in MMA, punches can be masked by the threat of a kick, takedown, or various other techniques. Floyd uses this to his advantage like the genius he is and allowed Conor to expend most of his energy in rounds 1-5. Floyd essentially sacrificed rounds on the score card in order to allow his superior conditioning and experience advantage to shine in the later rounds.

In combat sports, pacing is just as important as the size of the gas tank. Much like how a runner paces their marathon, combat sport athletes must hone in their internal pacing skills, as well as adapt it on the fly, to any strategies the opponent employs. If Conor had started much slower, he would have lasted 12 rounds, but deep down, I'm sure he knows his most likely path to victory is scoring a TKO in the early rounds - which means starting slow was never an option in the first place.

Taken from Thesun.co.uk

Taken from Thesun.co.uk

The quality of training partners can also be up for critique. Conor has most likely been through several 12-round simulation sparring matches during camp, but the problem is that his quality of sparring partners were not up to par. Conor may have lasted 12 rounds in camp, but at a much lower power output than what was seen in the fight. Aside from a rusty and de-conditioned Paulie Malignaggi, there were no elite level boxers in his camp to challenge him. Leaving the ego aside and allowing more sparring sessions with Paulie as well as Andre Berto (who considered training with Conor before the Conor-Paulie fallout drama) would have increased his chances of success.

Punch economy

Running economy is defined as the energy demands for any given submaximal velocity of running. Punching economy is very similar and would be defined as how much physiological energy and how much cognitive resources is being spent on punches and shot selection. Only factoring VO2max and lactate threshold is not enough to predict endurance/conditioning performance, but how efficient the energy and oxygen expenditure is with each punch. When runners talk about running economy, they usually refer to the running technique themselves: stride length, torso angle, arm motion, even type of footwear. Punch economy then, can be broken into it's technical counterparts such as: arm reach, jab length, hand position/recovery after a punch, etc. As an example, below is an example of the many factors involved in running economy, from there, we can draw parallels to upperbody punching. 

Taken from www.fellrnr.com

Taken from www.fellrnr.com

Even if all physiological parameters were even between Conor and Floyd, the amount of psychological-cognitive effort Conor expended is much larger. While Floyd's pattern cognition is genius-level in terms of boxing and shot selection is pretty much second nature, Conor psychological stress from not being able to land shots also contributes to his physical downfall.

Concluding remarks

It's not fair just to say Conor doesn't work hard enough, or it all boils down to the fact that Conor is a "25 minute fighter". The demands of boxing are slightly different than of MMA, but it's only fair to acknowledge that both physiological and psychology factors. Simply put, Conor expends more energy per punch and the uses more cognitive effort for shot selection and pattern recognition, leading to his downfall. 

Nonethless it was a very exciting fight. There are many questions to be answered in the next few months. Will Conor go back to MMA or stay in boxing for a fight with Paulie? How will Conor's boxing skills transfer back over to his MMA performance? Who will he fight next if he goes back to MMA? Ferguson? Kevin Lee? Trilogy with Nate? Khabib? Max Holloway? 

Only time will tell.