big-biceps-triceps ASK ALFONSO

Ask Alfonso: Do Big Muscles Slow You Down?


Hi Alfonso,

I am taking a beginner college running class. The other day we ran 2 miles for a time & grade. I overheard the males talking at the end about their scores and heard one of the thicker muscular guys saying his time wasn’t as fast as the other smaller less muscular guys because he has too much muscle and his muscles use oxygen really fast, and therefore he isn’t as fast.

My question – is this true? I realize Olympic sprinters and distance runners have different bodies but at only 2 miles is your muscle mass really going to affect a run?




Hey Lisa, I had to answer this question!

The short answer is yes, having more muscle mass will affect performance, even at just 2 miles.

I’ve experienced this first handed. A few years ago I ran a 4th of July 8-mile race with a client of mine. She was all of 104 pounds and bounced like a Gazelle when she ran. She couldn’t understand why someone like me who was a trainer and regularly performed cardio type exercises was slower and breathing heavier. In her mind, logic dictated that I should have run faster and easier.

But think about it – what calls for oxygen during exercise? Your muscles do. So it follows that the more muscle you have, the greater the call for oxygen, hence you breathe heavier. For me, I need to motivate my 215 pound body while running, which requires a great deal of effort and energy expenditure. Someone who gains muscle mass doesn’t always increase their endurance in a proportionate manner. I was hanging out with 2 pro bodybuilders about 15 years ago. These guys were giants, I mean just massive. They weighed in at over 300 pounds in contest shape! Let me tell you, WALKING was tough for these guys, I mean after a flight of stairs you’d think they’d just sprinted a mile. They had so much muscle and were so disproportionate that their muscle mass called for oxygen far beyond what normal requirements.

Another example is when I ran the Race For The Cure in NYC two years ago. That’s just a 5k so it comes out to just over 3 miles. I finished in respectable time but I can tell you that it was all of the thinner, less muscled runners that were flying by me. Believe me I tried, but I just couldn’t keep up. In fact at my heavier body weight everything I do elevates my heart rate more than when I was lighter. If I do a set of burpees, jumping jacks, even squats and jump rope, I’m sometimes huffing and puffing (check out my Workout videos for further proof!) And if you look within sports you’ll see the same. Watch a boxing or MMA match and keep track of the stamina, quickness and conditioning in the different weight classes. Every now and then you may see a genetic freak, but for the most part the lighter guys are faster, more nimble, have better endurance and conditioning and aren’t huffing and puffing by round 4 like the heavyweight monsters.

Now we also have to think about the style of training here. It’s true that my style of training doesn’t include much distance running these days. But I remember being 19 years old and at a weight of 165 pounds. I can honestly tell you I was a jackrabbit at that weight. I could go out and run 8–10 miles no problem. I recall running easy, efficiently and able to run that mileage multiple times per week. Now? No way. I’m simply not built for it. With the exception of people who are true mesomorphs, meaning they’re heavily muscled through genetics, most people you see walking around that carry extra muscle mass work very hard to gain and keep it. And that means the chances are that they don’t run very often and when they do, not for long distances.

Now whether or not the guys you mentioned were copping out I don’t really know. At just 2 miles, they shouldn’t have been that much slower. And just how muscular were they? Did they look like power lifters or bodybuilders, or just your average beach body gym rat? I have a feeling these guys may have used their muscle mass as an excuse. Ha! I’d be interested to see how much better they get in the coming months. Keep me posted!

All information contained within this site, Angry Trainer, is for informational purposes only.  It is not intended to diagnose, treat, cure, or prevent any health problem – nor is it intended to replace the advice of a physician.  No action should be taken solely on the contents of this website.  Always consult your physician or qualified health professional on any matters regarding your health or on any opinions expressed within this website. Please see your physician before changing your diet, starting an exercise program, or taking any supplements of any kind.


16 comments on “Ask Alfonso: Do Big Muscles Slow You Down?

  1. Wow! This really explains a lot. I don’t have huge muscles, however, I do have way more muscle then I’ve ever. I could not understand why a flight of stairs or a short sprint winded me so. I thought, surely, I’m getting “conditioned”.

  2. As you mentioned Alfonso, training style and genetics have a lot to do with this. In the end it mostly comes down to muscle fiber types (fast twitch vs. slow twitch) and that is mostly determined by genetics and somewhat affected by style of training. A bodybuilder should never try to be a triathlete and a triathlete should never try to be a bodybuilder. Well, I suppose they could try, it’s their choice, but I doubt they’re going to be successful.

  3. Wouldn’t the key then be to work on both strength and conditioning? I understand that there’s going to be some compromise, and you’re not going to be at your maximum in either direction if you train both. Like, obviously if you’re trying to be a powerlifting champ, then maybe you just have to deal with crappy endurance in order to lift as heavy as possible. But for us normal folks who just want to be more fit. I want to lift heavy things and breathe happily after climbing a flight of stairs. Is that an impossible goal?

  4. They absolutely do. Take a look at boxers, they have to be able to move fast for a long period of time.

    Or Mariusz Pudzianowski – All of his MMA fights so far were set for 2 rounds. He can’t go no more even though he lost a lot of muslce in order to improve his speed and endurance.
    Still he was breathing heavy in the very first round against Tim Sylvia.

    44-year-old Randy Couture was whipping on Sylvia for five 5-minute-rounds.

    I don’t know how it is with balance and coordination. Does muscle affect that also?

  5. Coordination is mostly improved by simply practicing whatever skill you’re trying to improve. Meaning, if you want to get better at coordinating a tennis serve, then you better practice serving tennis balls. Research shows that 10,000 hours of practice is when the level of “expert” is reached. I’m sure some can argue against that though. Increased strength can improve the performance of your serve but not the coordination of it. Increase lower body strength has also been directly correlated to improved balance (particularly in elderly people). Check out this blog article for more in it if you’re interested: It’s a little “sciencey” but provides some good research on the subject.

  6. i don’t know about this because i’ve gained alot of muscle in the past three years and my distance running got better and i’m able to run at a faster pace for a longer period of time.

    • I can confirm that. But I think I received better stamina / speed because I got stronger with non-hypertrophy training, so it’s not because I gained muscle / size.

      @ Thanks – Thanks.

  7. I don’t agree much. Angry trainer bases his answer as an excuse for his low stamina. I’ve become faster after I’ve gained 12 pounds of muscles. It depends on how you train.

    Of course, if you don’t do much distance or stamina training and gain weight (even if it’s all muscle), you won’t have the same stamina when moving the additional weight.

    I really like Angry Trainer, I read it every day, but I’m a bit disappointed by this answer.

    • ” Angry trainer bases his answer as an excuse for his low stamina”. Alex, number one I don’t make excuses and number 2, who said I had low stamina? The question wasn’t about stamina or endurance, but speed and whether having more muscle slowed people down. And the answer is yes. How many marathoners do you see running at 215 pounds of muscle?

      If you’re going to criticize me, please read the questions and answers thoroughly. As for me, my endurance and stamina is great!

      I’m glad you like the site though. I guess I can’t win them all.

  8. Hi Angry Trainer,

    I don’t agree with you either. You don’t see PROFESSIONAL marathoners running at 215 pounds, but if you have ever been to a marathon, you can see runners of all shapes and weights.

    I went from 140lbs to 162lbs after starting weight training, but I never stopped doing my speed sessions.

    Of course I got heavier, but I also got extra power. My legs are also bigger.

    Maybe you are not as fast because you don’t train for speed. But believe me, it’s possible to train for speed and for strength.

    I think you are basing this article in biased personal experience and anecdotal observations, rather than solid reasons.

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