Intro To Fast Twitch Vs. Slow Twitch Muscle Fibers
In this video I want to explain to you guys a very, very important concept that there’s a lot misunderstanding about in the gym among the gym members and the trainers themselves, so this issue deals with:
- How you gain muscle…
- How to grow muscle…
- How muscles work…
- The difference between fast twitch vs. slow twitch fibers…
- What intensity levels you should train at…
- How many reps should you train… high reps, low reps, etc.
- Should you train for strength or endurance?
So in this video I’m going to answer all these questions for you but before I do I want to go through it step by step so you can understand it.
If you do a Google search on:
- strength versus endurance muscles
- fast twitch versus slow twitch
- fast twitch vs. slow twitch muscle fibers
- high reps versus slow reps
… and all these things on Google, on YouTube, you will find there’s a lot of “conflicting” information or a lot of “incomplete” information regarding the difference between the fast twitch vs. slow twitch muscle fibers.
The reason why is because most people really don’t understand the science of fast twitch vs. slow muscle fibers so they are unable to maximize their muscle and strength gains.
You have trainers out there that will understand the muscles in theory but they don’t understand it in application.
So they have theoretical knowledge but they don’t have the experiential knowledge.
So in this video I want to share something with you guys that I have spent over a decade of doing research and experiments on prisoners that I used to train as a volunteer and I’m going to share with you what I discovered during that time.
What Is Muscle Intensity?
I’m going to start off first by showing you guys about this intensity level scale right here…
… scientifically, it means that the level at which you exert your muscles and how much of your muscle capacity that you use.
Now the way that you understand this is that…
The muscles in the human body have between zero to 100% capacity. The area around the 60% level of your muscle capacity is very important because this is where your body deactivates the slow twitch muscle fibers and begins activating the fast twitch muscle fibers.
It’s NOT precisely at 60% for everyone but it’s generally around that area.
Anything that you do that’s below 60% of your maximum muscle capacity activates what is called your slow twitch muscle fibers, it’s very easy to remember these red (slow twitch) fibers because:
- They transport all the blood.
- They are used for endurance exercises.
- They are used for conditioning exercises.
- They are used for all long distance activities or any “long length of time” type of training.
That’s the purpose and function of the slow twitch or endurance muscle fibers.
Sometimes you’ll hear in the textbooks and in the magazines and the videos on YouTube and Google that these slow twitch muscle fibers are called your “red muscle fibers”
So these slow twitch muscle fibers have many names but regardless of what it is, I just simply call it your “endurance muscles“.
When you train over 60% of you capacity… for example, if you’re able to lift a 100 pounds for your 1 Rep Maximum and you can lift beyond 60 pounds (which is 60%) of your 1 Rep Maximum then this would be considered working your “fast twitch muscle fibers“.
The fast twitch muscle fibers are what I call your “strength fibers” or your “speed fibers“.
The fast twitch muscle fibers are what you use to do:
- explosive, split second runs
- sprints & jumps
- 100, 200, 400 yard (meter) dashes
The slow twitch muscles fibers are being used when you’re doing a marathon running or when you’re walking and things like that.
If you ask most trainers and gym members… they don’t even know when the body activates the fast twitch vs. slow twitch muscle fibers.
At what point the body activates the fast twitch vs. slow twitch muscle fibers is extremely crucial to muscle and strength gain success.
You can get really good results at the gym (as well as be an excellent personal trainer) if you clearly understand when the body activates the strength and the speed (fast twitch) fibers and when it activates the endurance (slow twitch) fibers.
Before you understand how and when the fast twitch vs. slow twitch muscle fibers are activated… you have to understand why the human body has these two different types of fibers.
Difference Between Fast Twitch Vs. Slow Twitch Muscle Fibers
Keep in mind, the word “twitch” means “to contract”, so a fast twitch muscle fibers simply means it can contract faster than a slow twitch muscle fiber.
The reason why your body has two different types of muscle fibers (fast twitch vs. slow twitch muscle fibers) are for survival reasons.
Through evolution the human body has evolved to become a “surviving machine”.
In order for you to survive many thousands of years ago such as running away from a saber-tooth tiger or from Tyrannosaurus Rex or from any kind of danger, you had to have the ability to just explode and get out of the way as a hungry lion is chasing your ass down and trying to take a bite out of our ass.
So because of that, Mother Nature evolved the human body so that it has these strength and speed (fast twitch) fibers so that you can explode and get the hell out of the way and run to safety.
Now these endurance (slow twitch) fibers are normally used for just everyday activity.
For example, if I’m lifting some pencils or markers or I’m just walking around the house and picking up paper or typing on the computer, then it uses these endurance (slow twitch) fibers because it doesn’t have to contract quickly or rapidly.
It doesn’t have to contract very fast because my life is NOT in danger. In other words, typing faster or slower or lifting a pencil is not a life threatening activity.
On the other hand, the strength and speed (fast twitch) fibers… they contract very fast, so that when you need to haul ass and get away from danger they can contract quickly and rapidly and get you out of danger or harm’s way.
I want you to clearly understand that the function of the fast twitch fibers are to protect and provide for safety.
I put a lot more emphasis on the fast twitch muscle fibers because they are very unique when you are trying to gain muscle size and strength.
Because it’s the ONLY muscle fibers that can GROW and INCREASE IN SIZE within the human body after puberty!
You will also hear the fast twitch muscle fibers often referred to as:
- White muscle fibers
- Type IIa and Type IIb muscle fibers.
On the other hand, the slow twitch muscle fibers are often referred to as:
- Red muscle fibers
- Type I muscle fibers.
I differentiate which fiber is which by remembering that cardio and aerobic activities require more oxygen to be delivered to the muscles so…
… that means more blood flow to the muscles, and since blood is red…
… I can remember that the “red muscle fibers” are the slow twitch fibers because your muscle fibers do NOT have to twitch (contract) fast to perform the exercise.
On the other hand, I remember the fast twitch fibers by thinking of the muscles as being “fast as lightning”…
… and since “lightning” is colored white, then the fast twitch muscle fibers are also the white fibers.
Plus, the fast twitch fibers require less blood flow therefore they have less “color”, therefore they are white fibers.
You can easily be confused as to the functions of the fast twitch vs. slow twitch muscle fibers and I find that the easiest way to remember them is just to remember that:
- The slow twitch fibers are called the endurance fibers.
- The fast twitch fibers are called the strength and the speed fibers.
When you are at the gym you will also hear some people refer to the fast twitch vs. slow twitch muscle fibers as:
- Aerobic fibers for slow twitch fibers.
- Anaerobic fibers for fast twitch fibers.
What Is The Best Training Intensity Level For Fast Muscle Gain?
The next obvious question that comes to mind is…
What is the optimum intensity level to train at for fast muscle size and strength gains?
Should you train below 60% or above 60% of your maximum muscle capacity?
Now the answer to that depends upon what it is that you’re trying to do.
If you’re trying to burn body fat, then you want to train BELOW 60% of your maximum capacity, because these are the fibers that burn the most fat.
If you want to train for muscular size, strength and speed, then you want to train ABOVE 60% of your maximum capacity because those are the fibers that are responsible for those high intensity tasks.
How Much Fast Twitch Vs. Slow Twitch Muscle Fibers
Does Each Person Have?
The ratio of fast twitch vs. slow twitch muscle fibers in everyone’s body is very similar in proportion.
Normally, the average ratio of the strength/speed (fast twitch) fibers to endurance (slow twitch) fibers in the human body is a 50:50 ratio.
In other words, the average person will have 50% strength/speed fibers and the other 50% will be endurance fibers.
These two types of muscle fibers are interweaved next to each other throughout the skeletal muscles in your body.
In case you forgot, the skeletal muscles are responsible for moving all the bones and articulating all the joints in your body.
Now, obviously, you have world class athletes like Ben Johnson, Michael Johnson, Muhammad Ali, Mike Tyson, etc. who have a disproportionate amount of fibers and are born with more fast twitch fibers then slow twitch fibers.
These athletes have more strength/speed fibers than they do the endurance fibers.
For example, they might have as much as 60% or even 65% of strength/speed (fast twitch) fibers and only 35-40% endurance (slow twitch) fibers.
Most professional athletes in highly explosive or strength intensive sports will have more strength/speed (fast twitch) fibers than they do the endurance (slow twitch) fibers.
On the other hand, if you look at some of the marathon runners, they’ll have more of 60 or 65% endurance (slow twitch) fibers, versus the strength/speed (fast twitch) fibers, and that’s how these athletes are able to excel in their respective sports.
What Is High Intensity Training?
Normally if you are training at the gym, there’s a lot of people that will say they train high intensity by doing a lot of obnoxious screaming, yelling, and making funny, ugly faces and stuff.
To me that’s not high intensity training. It’s just a bunch of dumb asses trying to showoff and get attention at the gym.
Here is the correct definition of high intensity training:
High intensity training is training that is done at or close to 100% of your maximum muscle capacity!
For example, I can bench 325 pounds for a 1 Rep Maximum, if I’m only benching 100 pounds in my workout then that means I’m training at a very low intensity level because it is only utilizing 31% of my chest capacity.
If I’m training near 300, 315, or 320 pounds, that’s almost near the maximum weight that I can bench press so that would be considered high intensity training.
The advantage of training at a higher intensity level is that you can gain muscle size and strength much faster. However, the risk of injury is also extremely higher.
Therefore, I do NOT recommend you train above 90% of your maximum muscle capacity unless you have a bad ass trainer such as myself working with you to make sure you are doing it correctly.
When you do not have professional training, then just stay between 60-90% of your 1 Rep Maximum.
Summary Of Fast Twitch Vs. Slow Twitch Muscle Fibers
When your goal is to gain muscle size and strength, you need to know that the big differences between the fast twitch vs. slow twitch muscle fibers in your body.
Here are some common names for the fast twitch vs. slow twitch muscle fibers:
- Fast twitch muscle fibers (a.k.a., white fibers, Type IIa, Type IIb, anaerobic, strength/speed fibers, etc.)
- Slow twitch muscle fibers (a.k.a., red fibers, Type I, aerobic, endurance fibers, etc.)
The word “twitch” means “to contract” so a fast twitch muscle fibers simply means it can contract faster than a slow twitch muscle fiber.
It’s important to understand the difference between the fast twitch vs. slow twitch muscle fibers because you want to train the right fibers depending upon what you are trying to accomplish with your workouts.
- If you want to get bigger, stronger, faster, etc. then you want to focus training ABOVE 60% of your capacity in order to activate the fast twitch fibers because they are the ONLY fibers in your body that can grow bigger in size.
- If you want to burn body fat or have more endurance, then you want to focus training BELOW 60% of your capacity in order to activate the slow twitch fibers because they burn more fat and get more oxygen to last longer.
Now that you have a better understanding of the differences between fast twitch vs. slow twitch muscle fibers and how it affects muscle gain, let’s move on…
In the next section on How To Gain Muscle, I’m going to clearly explain:
- The importance of training the correct reps.
- The ideal rep range to gain muscle fast.
- The ideal rep range to gain strength quickly.
So keep an eye out for my next email!