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Why Are MMA Fighters Skinny And Don’t Have Big Muscles?

Photo Credit: Vengo Films via Wikimedia

In the minds of many fans, the most capable fighters are the ones with muscular bodies and big biceps. They often tend to associate bulky bodies with the type of strength you need for fighting, which is wrong. 

MMA fighters are skinny because their training primarily focuses on high-repetition workouts. For example, fighters do 100 pushups rather than bench press 400 lbs. High-repetition workouts do not lead to big growth in muscles, but it keeps fighters resistant to muscle fatigue. 

In reality, MMA is all about being fast, agile, and having great endurance. And MMA fighting is one of the few sports where big muscles don’t play a vital role and it’s actually counterproductive to have big muscles. As such fighters tend to be skinny to be conditioned for fighting than bulky physiques.

In this article, we will explain further why having big muscles actually hinder fighters’ athletic performance which is the reason why many fighters are skinny.

Muscle Endurance Is More Important Than Muscle Growth

MMA fighting is like a marathon which requires endurance. Your body need to be prepared for 5 rounds of fast-paced fighting by developing muscle endurance. For this reason, MMA physical training primarily focuses on high repetition workouts such as 100 pushups rather than trying to bench press 400lbs of weight set a few times. High-repetition workouts do not lead to big growth in muscles, but it improves muscle endurance, keeps body resistant to muscle fatigue. 

In other words, instead of having bulky bodies, they focus on building strong muscle endurance and keeping their body fat low at around 5-9 %. Just about every fighter prefers to have low muscle mass as it helps them to last longer in a fight.

Here is another illustration of how it works. Big muscles are great for explosive strength which works in anaerobic sports like powerlifting or football. They allow you to use as much explosive strength in a short period of time to lift a heavy object or run a 100m sprint as fast as you can. However, raw power without endurance means nothing in MMA. 

MMA is a different form of activity in which you need to perform at a high pace over an extended period of time. Instead of increasing muscle mass, fighters focus on muscle endurance training that makes them lean and shredded.  This type of skinny body allows them to perform at the best of their abilities without a sudden decrease in performance.

Imagine yourself sprinting across a field as fast as you can. You’d be tired. Now imagine sprinting across that field with a tiger chasing you…between the fear, adrenaline and work from sprinting, you’d be beyond exhausted. That’s what a martial artist deals with every time he steps in a ring.

Former UFC champion Cody Garbrant, Source

Big Muscles Burn Up Oxygen Quicker

Fighters avoid building big muscles as this speeds up the depletion of oxygen and get tired easily. Bigger the muscle, the bigger the intake of oxygen it requires.

When you exercise, your muscles consume oxygen to produce energy…


As a result, if a fighter adds big muscles to their frame, their heart would have to work much harder to pump in more oxygen used by big muscles. This results in a higher heart rate during the fight and lack of breath very early in a bout. 

That said, MMA fighters are careful not to build too much muscle mass while training for a fight. They focus on finding a balance between adding enough muscle mass to be strong and having top cardio. On top of that, most of them keep their body fat low which makes them look skinny. 

The best example is a fight between the former UFC champ, Tim Sylvia and Mariusz Pudzianowski. For the ones who are not familiar with him, Pudzianowski is an oversized muscular man and a former “Strongest Man” world champ. The trouble was, his big muscles were built to burn oxygen quickly but deliver huge power in a short period of time. This was the total opposite of what he needed for MMA. 

Even though he looked strong with all those muscles, he was running out of breath after a couple of exchanges. His huge muscles burned up all the oxygen in the opening minutes and he ended up being TKO’d in the second round. 

In MMA, big muscles won’t win you fights simply because they force your heart to work much harder which leads to quicker exhaustion. If having bulky bodies was beneficial in fighting, then all fighters would look like bodybuilders.

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Big Muscles Make You Less Flexible And Slower

Big muscles make you stiff and restrict your range of body movement, which is not good for MMA. Israel Adesanya, an elite MMA fighter, is not a fan of increasing too much muscle mass as he said the following:

Yeah, sure, you want to put on size? Alright. Is your body used to being that heavy? Are you used to moving around that heavy with the work-rate you were doing with all your previous fights? Yeah, I just don’t play the game like everyone else…


Carrying big muscles hinders you from performing striking or grappling techniques the right way. Instead, fighters prefer being skinny to be flexible as this makes them faster and more powerful. But, how less muscle mass makes you more powerful you may ask?

You see, having big muscles doesn’t mean one can strike hard. The power of every strike comes from the rotation of your entire body, notably your legs and hips. Not having over-developed muscles makes a fighter more flexible and allows them to rotate their entire body faster, generate more power and speed in a strike. 

The same stands when it comes to ground fighting that requires grappling as well where flexibility really comes into play. It allows you to switch between the positions faster, create a space to get up or escape from a choke or joint lock. 


Are Skinny Fighters Better In MMA Fighting?

The data indicates that relatively skinny MMA fighters who don’t have big muscles tend to do better in MMA fighting. If we look back in history, most UFC champions have been thin and they didn’t have much body fat, regardless of the weight class. To prove our point, here is a list of some of the greatest UFC champs in history who were/are relatively skinny:

  • Jon Jones
  • Anderson Silva
  • Israel Adesanya
  • Khabib Nurmagomedov
  • Georges St. Pierre
  • Jose Aldo

Skinny fighters tend to move faster, are more flexible and have better endurance. The ones with bulky bodies, on the other side, tend to gas out early in the fight as big muscles burn more oxygen. On top of that, they are much slower simply because they have more mass to move.

With a good game plan, skinny fighters would always outlast a fighter with big muscles. They would also win most of the exchanges on the feet or ground because they are faster and more agile. 

Brothers Nick and Nate Diaz are a great instance of how skinny fighters win their fights. Even though they look like average people, their endurance is second to none. They have won most of their matches by outlasting their rivals and beating them in later rounds. 

Who Were The Best Skinny Fighters In MMA History?

In MMA history, there have been many great UFC fighters who were skinny. In fact, some of the most dominant UFC fighters have been the ones with low muscle mass and body fat. Here are some of the most famous ones:

Jon Jones 

Jones is perhaps the most gifted MMA fighter we have ever seen fight in the UFC. One of the secrets behind his success are his superior athletic abilities. He is tall, skinny, and has a very low body fat compared to most of the other fighters from his division. 

In his career, Jones went through many 5 round wars and we are yet to see him gassing out in a fight. The best instance is his first fight with Alexander Gustaffson at UFC UFC 165 in 2013 which he was losing in the early rounds. But Jones would win that fight by outlasting Gustaffson and winning the later rounds. 

Israel Adesanya

Adesanya is an ideal instance of how being skinny helps you in MMA. Don’t look any further from his bout with Paulo Costa if you want to see what’s more important in fighting. It was an epic battle between a skinny fighter and a fighter who looks like a bodybuilder. 

Coming into this bout, Adesanya looked half the size of Costa who had huge muscles on his frame. But, Costa just couldn’t keep with Adesanya’s speed, agility, and endurance. He came into the second round looking tired and beaten which resulted in him getting TKO’d.  

George St. Pierre

GSP is often seen as the best fighter of all time who has never been a big bulky fighter carrying a lot of muscles. Instead, GSP has always been lean and shredded simply because he preferred to outlast his opponents in a fight. As a result, he has never looked tired and he won many 5 round bouts, often fighting at a high pace. 

In some way, GSP has just the right amount of muscle mass that allows him to last longer while still being very powerful. Or in other words, GSP has good cardio, but at the same time, he has enough muscles to score explosive takedowns. He used this combo of endurance and relentless wrestling to win many of his matches.

Do MMA Fighters Lift Weights?

Yes, MMA fighters often lift weights but with a different purpose than bodybuilders. Their main goal is to build muscle endurance and the way they exercise differs from the way other people exercise to build big muscles. 

The weight MMA fighters lift is often less than 50% of the maximum weight they can lift to do one repetition. For instance, MMA fighters prefer to lift around 30 lbs and go for 30 reps instead of lifting 100 lbs a few times. As a result, they will keep their body fat and muscle mass low and won’t get bulky like bodybuilders.

Being thin and having strong muscle endurance means a fighter can last longer in a fight. It also makes a fighter more agile and faster than the opponents who have big muscles. 

Does Weight Lifting Help You In MMA?

The answer to this question is really based on what type of weight lifting we are talking about. For instance, being able to lift 500 lbs on the bench press is a great achievement, but this means nothing in MMA where you must focus on being agile and fast and throw over 200 strikes per match. 

Lifting weights for MMA is all about high repetitions and building muscle endurance over heavy lifting to develop big muscles. Lifting 30 lbs 100 times is far more important for MMA fighters than lifting 300 lbs a couple of times. Fighters need to exercise in a way to keep their bodies lean and shredded. 

By doing so, they can exchange strikes or grapple for 5–5 minute rounds in an MMA match and not gas out. If they focus on lifting heavy weights with few reps, then they would not last a single round because big muscles fatigue much faster.