Building mitochondria in fast twitch fibers

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    Topic
  • #8165
    xcskier
    Participant

    Since fast twitch fibers don’t come with mitochondria
    they have to use glycolitic processes to generate energy
    (and therefore produce lactate).

    There’s also been some interesting Russian research done by
    Seluyanov on building mitochondria in fast twitch fibers
    (type IIa). If I understand the training methodology correctly,
    you perform some high intensity work followed by long rest period
    so that no lactate is generated. Here’s a demonstration:

    (in the video Seluyanov suggests 10 repetitions with 2-3 seconds
    pause after each rep)

    I am wondering if anybody has tried this path and what the
    outcome was.

  • Keymaster
    Scott Johnston on #8178

    All muscle cells have mitochondria. In fact every cell in your body (besides red blood cells) has mitochondria. Mito provide the life force for……..life. But you are correct that Slow Twitch (ST) have greater mito mass then do FTa and much more that FTb. There is some evidence that FTa fibers can shift toward ST fibers by developing aerobic qualities like increased mito density and better capillary networks. There have been many studies done on rodents that show fiber type shifts but only one long term that I know of, done by Heikki Rusko studying a group of high level Finnish junior XC skiers as they trained and aged. He saw the number of what would fall into the ST category increase and FTa types decrease indicating that the FT had become more like ST and developed better endurance.

    OK, Now you got me going so hold on as I have a lot to say about this.

    Only the fibers recruited during the exercise get the training effect. So long duration low intensity exercise trains ST fibers because the force requirements are low. High intensity training, because of the higher forces necessarily recruits FT fibers. If those fibers stay in use for long enough (close to their endurance limit) then they will see an endurance training effect. So, when you do 15 reps with 80% of your 1RM max squat weight many FT fibers need to be recruited. By the 15th rep many of them are at their endurance limit and will see an endurance training effect.

    So none of this is new. We cover it in some detail in our book Training for the New Alpinism on page 125 including the sidebar on that page. There’s a lot of good info in that book :-). There are many ways to train the local muscular endurance that you are referring to. The principles are fairly simple: Recruit the “limit” fibers to do the work. These are the most powerful of the FT fiber pool needed to accomplish the task for the duration required. So requirement #1 is that the load must be relatively high. By relatively I mean it will be higher for short events than for longer distance events. #2 keep those fibers working for a long enough time right at their endurance limit so that get an endurance training effect. Voila, those fibers will develop more endurance. For endurance; duration of the training is the key factor, even for these FT fibers.

    This is the training effect we are accomplishing here:

    Vertical Beast Mode: What Is Muscular Endurance? Why Is It Important and How Do You Train It?


    and here:

    Muscular Endurance (ME) Workout: Water Carries

    This is exactly the theory that underlies all these fad HIIT exercise schemes like CrossFit although the Kool-Aid drinkers don’t have enough knowledge to know this has been well understood for 60 years and like to claim that they have discovered something new. In fact they badly misapply the principle…….but that is another story.

    Yuri Verkhoshansky wrote extensively about this in the 60s and the methods to accomplish it a varied depending on the duration of the event you are training for. The method I have used most successfully is what He called: Specific Locomotion Executed in More Difficult Conditions. There is nothing new in training. Any breakthrough is merely a recycling of old ideas dressed a bit differently.

    We only use what Verkhoshansky calls LME (Local Muscular Endurance) training during certain stages of the train cycle. For an XC skier it is often done in the early base period to provide a ME base for more aerobically taxing interval training latter. For mountaineers we use in the later stages of training for the less well trained and for longer periods with the highly trained. Steve did this training in certain phases of his preparation. I used this to good effect with Sadie Bjornsen, her brother Erik and with Torin Koos. Names that skiers may be familiar with.

    It is vital that the aerobic base training volume be kept high during this LME period

    I’ve written about that extensively on these forums (look under Muscular Endurance on the index to your right) and in the articles linked but you have been warned. As I recall from your recent forum posts, it seems very likely that your have ADS (Aerobic Deficiency Syndrome)> You should NOT be using this training. At least not now until you improve your aerobic capacity so your HR does not go so high when you go uphill. Doing LME will negatively impact your aerobic base training. That’s why for less trained mountaineers we put it late in their programs: We hope to get there AeT up higher before applying it. For the well trained or the World Class XC skier can come early in he base period because they have a high AeT already.

    The higher your aerobic base capacity the more you can expect to gain from LME training.

    Scott

    Participant
    xcskier on #8182

    Thanks for detailed reply.

    For some reason, I thought that local muscular endurance
    training was different than what Seluyanov (who was
    Verkohoshansky’s student) is proposing. I am talking about
    the biochemical mechanisms that may elicit mitochondria
    growth in IIa fiber types. But maybe there are just different
    paths to get to the same goal (and the reason why it happens
    may not be relevant for training purposes).

    Another mitochondria related question is about some research that
    showed that elite athletes have much higher mitochondria density
    and that endurance training causes this density to change:
    http://www.celemans.com/pdfs/2016%20Nielsen%20et%20al%20J%20Physiol.pdf

    I am wondering how much of this is genetic and how much can this
    be changed with training.

    Keymaster
    Scott Johnston on #8184

    Since I do not speak Russian I could not understand a word of what he was saying. I’ll take your word for it that his prescription is 10 reps with 2-3 seconds rest/rep. It the weight was high enough I can see how this could have an endurance training effect. The LME training or any endurance training for that matter causes biochemical adaptations so. When you do some endurance training you hope to create a situation in the muscles where they can not supply he required energy. You put them in to a crisis state. The response is to cause a cascade of biological signals that cause certain genes to respond but up regulating (doing more of what ever they are meant to do). This results in some protein synthesis (like more mitochondria) so that when the next time this training load is applied the system can respond better and cause less of a crisis situation. That is what the training load must progress as you become fitter. You have to cause a small crisis each time you train if you hope to continue improving. This is all a biochemical process.

    I can only comment on the process we have used with considerable success all of which should (according to theory) result in increased mito density in FTa fibers. As far as increasing the surface area of the mito inner membrane that the study looked at: Do not get so far down in the weeds with the physiology that you loose sight of the trees. This study does not address any training specifics as far as I could tell.

    Be aware that the sports scientist rarely (almost never) Come up with training innovations. It is the coaches who do this and then the scientists come along later and figure out why it works.

    Instead of perusing scientific journals for information on how to train; look instead at what the best coaches and athletes do: https://www.frontiersin.org/articles/10.3389/fphys.2017.01069/full

    I think you can find all the information you need here to build a good XC training program.

    Scott

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