[Rumbling music] If I were to take a spoon and scoop some Cheerios on it, and do that, that’s a bicep curl. What’s the difference between [SEE VIDEO]…that, and putting a 60 pound dumbbell and doing a bicep curl? It’s the exact same movement, but it’s VERY different. And what’s the difference if I do this? [SEE VIDEO] Or if I do that? [SEE VIDEO] [Silence] If we take… If we strip the skin off and just talk about this muscle. Let’s just talk about the Bicep, right? Something’s happening. It’s the same engine. But, how is it that I can use the same muscle to create a low-velocity, low-force movement? Or high-velocity, low-force movement? Or (here’s my “emperor’s new weight”) 60lb dumbell with a high force, low-velocity movement? It’s all the same muscle! How does the nervous system….? [Male speaker] Different types of fibers? [Rage] Okay. So there’s different types of fibers… Everyone’s heard of fast-twitch / slow-twitch. There’s muscle fibers, and there are nerves connected to those muscle fibers. The nerve carries the signal, the
muscle fibers contract. A Motor Unit is a muscle fiber, and it’s innervating nerve. PLEASE don’t call them “fast-twitch muscle fibers” and “slow-twitch muscle fibers!” They’re MOTOR UNITS! The other thing is: Activation Capacity. So I got these Fast Twitch and Slow Twitch Motor Units, and then a whole range of them in-between. I’m using a small percentage of them
to do this [SEE VIDEO]. And I’m using a different percentage of them to do that [SEE VIDEO]. So that’s called Activation Capacity. We want to get to 85 – 90 percent Activation
Capacity. We want to…whatever muscles we’re using, we want to be able to recruit 85 – 90 percent of the Motor Units in that muscle, [Finger snap!] [WHAH!] Whenever we want to! Slow Twitch Motor Units go… have more endurance, but contract more slowly. The old school lectures, the old school science was, they were your endurance fibers. They’re the ones that your using if you’re running a marathon. True! But that led to a misconception that you’re either using Slow Twitch Motor Units or you’re using Fast Twitch Motor Units. You’re ALWAYS using some of everything. But in the explosive or high force movements you’re using pretty much everything you got [CHUCKLE]. Or everything you can. And that’s the activation that we’re trying…. Activation Capacity that we’re trying for is: GIVE ME EVERYTHING! (“Give her all you got, Scotty!”) Slow Twitch Motor Units can hypertrophy. They can get bigger. 20 years ago when I was first learning this shit, they said “No they [Slow Twitch Motor Units] don’t hypertrophy.” “Your Fast Twitch Motor Units are what hypertrophy.” Which is actually not true. Everything hypertrophies! Gets bigger. Hypertrophy just means: on a cellular level, it gets bigger. So your Slow Twitch Motor Units get bigger. Your Intermediate Twitch Motor Units, which… they are the ones that contract slightly faster than the Slow Twitch, but they’re not really Fast Twitch. They can get bigger. And your Fast Twitch actually have the least potential to grow. They also don’t have the mitochondria, or as many mitochondria in them, which is what has a lot to do with size and
mass, and… What’s really important to understand is that because of Specificity, you’ve got these, what we’ll call Intermediate Motor Units, Intermediate Twitch Motor Units, that CAN be coerced into behaving like Fast Twitch Motor Units OR behaving like Slow Twitch Motor Units. And that’s the golden nugget that’s useful for us. Goin’ “wait a second, if I train more explosively and faster, and… then I can actually develop, the athletic ability to be more explosive and…?!” YES. YOU CAN. This is where Mike Tyson and I disagree. Mike Tyson believes that punchers are born. I believe you can build an athlete. And I believe no matter where you are, You can get bigger, stronger, faster. The difference between a slow, or a non-forceful movement, and an explosive movement is Activation Capacity, the percentage of Slow Twitch versus Fast Twitch Motor Units that are recruited. And really, it’s the percentage of Fast-Twitch Motor Units that are recruited. Our goal is to coerce our nervous system into giving us as much Explosive Strength as
possible. [Finger snap!] Instantly! And then develop the fuel system capacity to do it over, and over, and over…and over… Hey, guys, listen. We are making the world a better place. We’re saving lives. SUBSCRIBE to my YouTube page. If you’re not on YouTube, if you’re coming across this through another venue, Facebook, whatever, LOGIN to YouTube and SUBSCRIBE! Thank you 🙂


  1. so, of i am mostly a slow twitch motor unit guy, is there a way in which i could change so that i have half fast twitch units and half slow twitch units. i want more power and speed than anything but, i am naturally slower than a lot of ppl.

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