Do Sprints Interfere with Muscle Growth – Q&A

Question: I recently came across the following comment on Bret Contreras’ blog with regard to a figure athlete he is training and a question about sprinting….

“I don’t have her do sprints. I have journal research that shows that sprints interfere with biochemical pathways involved in muscle growth.  While sprints will help pack on mass for beginners, it can actually negatively impact more advanced lifters in terms of hypertrophy. That’s why the bodybuilders don’t sprint or do plyos – the risk isn’t worth the benefits.”

The comment did not specifically cite the particular research, nor did it make mention of the sort of volume and distance of the sprints, i.e. whether this was low or high volume and whether the sprints were somewhere in the 10-40 yard range or beyond that range.

To the best of your current knowledge, is there a legitimate reason (biochemical or otherwise) why sprints would interfere with muscle growth? (I realize that with specific parameters and context this may be a bit tricky to tackle)   I am not necessarily arguing that figure athletes or bodybuilders need to be or even should be performing them, simply wondering if those who may do so would actually be compromising results as Bret seems to intimate.

Answer: The short answer to your question is that Bret is right; certainly distance probably will have an impact but when people talk about ‘sprinting’ for bodybuilders, it’s usually some form of high-intensity interval training (HIIT) being discussed.  That is, longer repeats (typically in the 30-90 second range).  Few would be doing short sprints like a track sprinter.

As to the mechanism, Bret is most assuredly referring to AMPk (adenosine monophosphate kinase) and how it impacts on muscular metabolism.   I wrote an article years ago about AMPk: Master Metabolic Regulator and talked about it in some detail in the Methods of Endurance Training series.

AMPk is activated, essentially, by alterations in the energy state of the cell: things that occur in both endurance training and longer sprint type training (AMPk is regulated both by the duration and intensity of activity).  Activation of AMPk has a number of implications: it’s involved in the adaptations to endurance training (stimulating various improvements to occur in the fibers in which AMPk is activated), increased fat burning, insulin sensitivity and a host of others.

Relevant to this specific issue, activation of AMPk has been shown to directly inhibit a molecular marker called mTOR (which stands for the mammalian target of rapomyacin, aren’t you glad you know that now ).  mTOR is a key player in muscle growth; for example, the amino acid leucine that so much has been talked about acitvates mTOR directly and this appears to be the major way that leucine/BCAA turns on protein synthesis.

So when you activate AMPk, via long-duration and/or high intensity endurance/interval training, this inhibits mTOR activity; inhibiting one of the prime players in muscle growth.  Again, that’s surely what Brett is referring to.

Now, as you bring up, this probably doesn’t hold for very short sprints but those would be uncommon for bodybuilders or physique athletes to do in the first place.  For the type of sprint/interval training commonly advocated for such athletes, I agree that the negatives would outweigh any potential positives when maximal muscle growth is the goal (interval training can have potential benefits for fat loss, including stubborn fat loss, as discussed in The Stubborn Fat Solution).

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21 thoughts on “Do Sprints Interfere with Muscle Growth – Q&A

  1. Maybe I’m a bit slow, but just so that I’m clear — are you saying that a 10-15 second sprint won’t interfere with muscle growth? At least to the extent of the 30-60 second HIIT you’re discussing here?

    I’ve been doing 6-10 sprints up a short hill with 90-120 second rest every Saturday for a few months now, and I’ve found them useful for conditioning and the somewhat less tangible goal of doing something athletic outside. (I have bad knees that only tolerate running when it’s up a hill.) I have to be careful not to overdo it and impede recovery, but generally I don’t feel noticeably more sore or gassed from this, nor has it gotten in the way of strength gains. Thoughts? Thanks!

  2. How much low or medium intensity cardio can you do before you activate AMPk? Is it only a question of duration or does frequency also play a role?

  3. On a similar vein to James, you mentioned that AMPk is activated “via long-duration and/or high intensity endurance/interval training”. Are there any tangible numbers as to what constitutes as long duration and whether the duration of the high intensity interval training can be manipulated to minimise activation of AMPk? Or would low intensity, short duration activity be the only way to avoid activation of AMPk so like short duration LISS?

    In addition I was wondering if high intensity strength training would not similarly activate AMPk since it would also cause a shift in the ATP/AMP ratio in the cells (from your methods of endurance training article) as you would use up ATP as well?

  4. Lyle,

    This is a quick question related to your comment about leucine and mTOR. While checking out Martin Berkhan’s writing, I read about how he would make use of pre-training BCAA’s if training in the fasted state. Would a straight up dose of leucine (say 5 grams) work the same or similarly as taking a suggested amount of BCAA’s, or would that basically be silly to just go with straight leucine instead of all 3 BCAA”s? This question mostly stems from the places I have seen selling bottles of only leucine sans isoleucine and valine.

  5. So then, could you offset the negative side affects (muscle building-wise) by taking leucine/bcaa’s before or after said HIIT training. not that i could really see a reason to be doing hiit training in conjunction with a mass gaining phase :/

  6. Now what about true all-out sprints? Not on a treadmill but on the track? I was thinking of doing 5 30 second all-out sprints with 1 minute rest in between, and eventually bumping up to ten. How would this affect fat loss without affecting muscle growth?

  7. So, football (soccer) that includes short bursts of sprinting does not fall in the above “muscle wasting” category of sprinting?

  8. I am with James on my confusion. Are you recommending the very short < 30 second sprints, which, in your words, are "uncommon for bodybuilders", if we are concerned with muscle growth interference?

  9. If sprinting can inhibit muscle growth, can it also be used to decrease muscle mass such as in the legs? I’m in the middle of longterm fat loss (100+ lb) and I suspect I have more muscle in my legs and calves than I eventually want.

    Thanks.

  10. This is a fantastic post.

    I really appreciate you posting the actual biology behind HIIT and it’s interference with muscle growth.

    I know that while supplementing my program with HIIT daily, I have had plenty of problems building mass when I wouldn’t otherwise.

    Thanks for a great post.
    Talk to you soon,
    Ryan “The Fat Loss Informant”

  11. Lyle,

    Hopefully you’ll answer this my comment even though this article is older.

    You said that shorter sprints wouldn’t have the same effect? I’m a skimboarder and (if you’re not familiar with the sport) it requires really short sprints when running out to the waves. The sprint is maybe 5-10 seconds tops, followed by riding and turning on the wave, which isn’t nearly as high intensity as the running part. Even then, the whole thing doesn’t total more than 30 seconds per bout.

    Would this severely hamper muscle gains? I realize that the answer is affected by other aspects such as how much rest between bouts, how long the entire sessions lasts (total number of bouts), and how frequently it is done, but is there a general answer you could give to this question?

  12. I do 9 sets of 15sec sprint, 10sec pause, also interested in this.

    Thanks for the article.

    I like to do these sprints and some functional training for a sport (15min hiit) on a ‘4th’ workout day on sunday (normal muscle training workout days Monday, Wednesday, Friday).
    Also would be interested about health benefits or not of sprinting.
    For me it’s just wanting to be able to sprint good, i also use it kinda partly instead of my legs training, and it just feels (and i guess i read somewhere) it’s a great workout for the lung and for heart. It’s obviously most taxing to my breathing, i breath heavy like 5 minutes after the workout (i am 10% bf btw).

  13. I don’t understand a word u were saying author….!!! please answer in brief
    sprinting for 30-40seconds for 4-6sets for 2-3 days in a week good or bad for advanced bodybuilder? just say yes or no!!!!

    but I was read several sites where it claims sprint increase testosterone, HGH and promotes muscle mass !!!! whats the truth???

  14. Bikram, technically speaking yes sprinting can increase muscle mass up to a certain point. But it gets to a level where this ceases. Sprinters are muscular, trust me, I’m a sprinter. But there is a glass ceiling there. Muscle will be gained to an extent, but if you are trying to build significant mass, as in the case of a bodybuilder, you will reach a limit and struggle to move beyond the mass possessed by the typical sprinter, unless you’re on the same drugs as Ben Johnson. The inhibitory mechanisms are explained in the article and are accurate.

  15. Sprinters get muscular by
    a. being black
    b. lifting weights

    Christian Lemetre (sp?) is a white 100m sprinter with minimal muscle mass at best. Sprinting doesn’t do jack crap for muscle in and of itself.

  16. Since we’re judging muscle mass based on arm size and definition, Julian Reus and other German sprinters definitely don’t look small to me.

  17. Nobody said they were small so that’s just dumb.
    But they are smaller than top bodybuilders now aren’t they?
    And I didn’t say that sprints PREVENTED growth now did I? As in you won’t grow at all.

    But add enough drugs and weights and genetics (blacks of West African Descent are jacked and it’s mostly genetic) and maybe there’s more to it than your simplistic observation.

    Ultimately, why would anybody do a non-specific (to hypertrophy) exercise and cut into recovery in the first place? It’s training that won’t HELP growth and can hurt it. So why do it? How hard is that to understand?

  18. Yeah, they are definitely smaller than drug-using top bodybuilders, but for the average person and for what’s achievable for natties they certainly don’t look small (not saying they are natty, by the way).

    I simply felt you were being unfair to white sprinters, that is all. Blacks of West African descent sure have the genetics for being jacked, but you’ll have to concede whites also have the genetics for muscularity/aesthetics in their own right, specially those of Northern European descent. That’s all.

    I didn’t infer that you said sprints prevented growth or that people should do sprints for hypertrophy, in fact I completely agree with you on this whole issue of cardio/sprints and hypertrophy just like on most topics of nutrition/training.

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