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.



If this video was helpful, show your support by clicking the social media buttons to share the videos to help me further my transformation 50,000 mission.

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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