Q: Brad, Did My Marathon Training Ruin My Leg Strength #LLTV


Live Sexy Lean

Fast Twitch Muscle Fibers vs. Slow Twitch Muscle Fibers

What’s up Live Leaners,

On today’s episode of Live Lean TV, I’m answering an interesting question I received from my Instagram…you are following me there right? OK, good Live Leaner.

The question went something like this…

I used to train for strength, I got bored, so I switched to marathon training. I’ve run my marathon, but I now notice I’ve lost strength’¦ SO’¦ I’m now back in the gym lifting weights. My problem is I notice I’m getting stronger in my upper body, but I’m not able to lift as much as I used too with my legs’¦what’s the deal?


It all comes down to your body’s muscle fibers…

Muscle fibers can be broken down into two different types. Fast twitch and slow twitch.

Slow Twitch Muscle Fibers

Slow twitch muscle fibers fire slower, so they are not as explosive, but they can go for longer periods of time before fatiguing. They’re mainly used for endurance training. So a marathon runner would use more slow twitch fibers.

Fast Twitch Muscle Fibers

Fast twitch fibers on the other hand, generate short bursts of speed and strength, but fatigue much quicker.  Sprinters and weight lifters would use more of these ballistic, fast twitch muscle fibers.

So as you can tell, the muscle fiber type you possess can influence which activities you’re good at. If you’re better at endurance sports like running, your body probably possesses more slow twitch fibers. If you can run fast and jump high, your body probably possesses more fast twitch muscle fibers.

So think about your goal…

Is it endurance based like running a marathon?  Or is it to get stronger, faster, and more explosive for a specific sport.

Whatever it is…

Your training needs to be focused on using those specific motor units and muscle fibers. 

So back to the original question…

…about why this person is gaining strength in his upper body but having a problem gaining strength back in his legs.

Well there is evidence showing that specific long-term ENDURANCE training can make fast twitch muscle fibers take on the properties of slow twitch muscle fibers in your legs.

So since you’ve been training for a marathon, the fast twitch muscle fibers in your legs may have taken on the properties of slow twitch fibers, thus you’re not able fire the leg muscles to lift as much.

Fortunately, the conversion is not permanent, and within a few months of continued strength training (probably 6 months), you should be able to fire up those fast twitch fibers and hit new personal best with your legs.

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Thanks for the question. And be sure to follow me on Instagram, since you can ask your questions there as well.

I also post pictures of my training and what I’m eating there a few times a day.

Also, lets get a conversation going in the comment section below.



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Lets also get a conversation going in the comments section below’¦

Are you currently training for strength, fat loss, or endurance? Leave your answer in the comment section below. 


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Questions For You:

– What are you currently training for: marathon, sport specific, strength building, or fat loss?

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34 responses to “Q: Brad, Did My Marathon Training Ruin My Leg Strength #LLTV

  1. I doubt one can change one type of muscle to another type, one muscle type
    might be more dominant than another .but like apples and oranges ,each are
    its own.

  2. hey brad do you have any idea how one can let his fast twitch muscles adopt the properties of the slow twitch muscle intentionally ??

  3. If you really desire to get shredded, you may want to Google the term “SSM Muscle Method”. You are guaranteed to get the muscles you want.

  4. My coworkers laughed when I told them I would bulk up with Morsch Muscle Madness, but then they saw the results. Google Morsch Muscle Madness to see their reaction.

  5. Have you heard about Cosmos Fat Loss? (check it out on google) It is a quick and easy way to lose weight fast.

  6. This must explain why I can walk 4 MPH for 2 or 3 miles (depends if I do weights or not) no problem but can’t seem to pull more than 20-25 lbs of weights with the ankle strap on my ankle. I’d actually love to run but my knees are shot. When I ran just 4 miles several times a week for exercise years ago, I had the best lower body.

  7. My classmates laughed when I told them I was going to bulk up with “H6x Muscle Monster”, but then I showed them the results. Google H6x Muscle Monster to see their reaction.

  8. BRAD…. I’ve just come across Spirulina …. have you heard of it before> Ihave trouble getting protein in unless through meat and fish, which I dont always want and this has a lot of protein…. YAY OR NAY???

  9. So Brad, is there specific exercises to do that can help speed up the return of Fast twitch muscle fiber?
    Also should you alternate between these exercises and more slow twitch exercises?

    I have followed a Hypertrophy specific training schedule for a while and it cycled through endurance to hypertrophy every 6 weeks or so. here’s the web site that I got the program from http://www.hypertrophy-specific.com/hst_index.html

    keep up the good work!

  10. hey brad thanks for some wonderful videos…one question i am recovering from a bad case of viral fever was out of action fro last three months..started working out from about a month now…how should i go about it..i see that i am recovering but i am feeling bloatness at times…

  11. Brad can u make a video on does your digestive system have to do with fat loss because I notice that all of a sudden I can’t poop the same anymore and I gained more fat since than, Idk what’s wrong with me

  12. So, what is better for fat loss? Fast or slow twitch fibres? Combo of both?
    Is it purely dependent what your goals are to what muscle fibres you focus on building?

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