Slow Twitch? Fast Twitch?

The few months ago, I was having a conversation with one of the coaches at the gym and I asked him why didn't I hear the coaches and trainers talking about slow twitch and fast twitch (a & b) muscle fibers when they were helping their clients?
Since I got a look that indicated that he didn't know what I was talking about, I further elaborated that it seemed to me that a person who really wished to build muscle needed to know the basic physiology behind muscle use in order to help with muscle growth.
Do Note: I like the coach and have a lot of respect for him but alas, he really didn't know what I was talking about and as I found out through some very candid research, quite a few people who are avid about their workouts do not either.
I hear talk and read about muscle health, muscle isolation, muscle groups and what workout works best for whatever but no one talks about what I consider a pretty important factor in doing what someone wishes to accomplish.

When I started my journey some years ago, I grabbed everything within reach in order to learn and stay alive and the physiology of muscle fiber was probably the most important lesson I came upon.
When I first started going to the gym, I looked and copied what everyone else was doing and notably, getting some decent results. But when I started doing the research, my workouts changed accordingly and the results are more than satisfying.
Understanding what's going on when I workout helps out with a better brain to muscle connection and my workouts are more pronounced and change in relation to what I wish to achieve and what types of fibers I wish to build on any given day.

After a lot of research I could probably write a book on the subject of the types of muscle fiber, what they do and how to work them not to mention the chemical and hormonal reactions which take place in them but in order to allow for some knowledgeable responses and honest questions, I think I will temporarily sustain until a later time.

Okay, I see that there might not be much interest in the thread but I can't just let it lay around without at least letting those who do NOT know what I'm talking about gain a little more knowledge of their own biological construction and why they feel as though they can or can't perform the same as other people.

First off, we know that we are all built differently and genetically inclined to do certain things. It's acknowledged that in order to be a body builder for instance, the genetics have to lean more in that direction the same as in the instance of being a world class runner. Not everyone, no matter the want or wishes is going to be able to build muscle mass the same as Arnold or Reg nor run mile after mile the same as some Kenyan runner does. But why?

The type of muscle fiber a person has been blessed with tells a huge part of the story. We all have three kinds of fiber which make up our entire muscle structure and that particular makeup, depending on which type of fiber a person is more prevalent to have or which one is more abundant, is pretty much what decides how we are going to react to whatever training we might employ.
Simply put and without going into more complicated stuff, those fibers are called: Slow Twitch, Fast Twitch IIA, and Fast twitch IIB.

Slow Twitch: Consisting of Red muscle fiber, has better oxygen use efficiency, is fatigue resistant and has a higher enzyme efficiency rating.
Generally speaking, a person with a greater amount of the slow twitch fibers has a better chance of becoming a long distance runner rather than a body builder who uses more:

Fast Twitch type II A muscle fibers. They are naturally larger in size than the slow twitch but are less efficient in the use of oxygen and other metabolites and wear out quickly. Then there are the heavy weight lifters who go into a third gear which are the:

Fast Twitch type II B muscle fibers. They are kind of a mixture of the previous fibers but only really kick in when the other two sets are overwhelmed.

The best example I have ever heard concerning what each category does is likened to a college kid hauling his box of books up to the third floor dorm.
At first, walking up the first set of stairs is fairly easy because the slow twitch, high endurance muscle fibers are doing their job but as the trek upstairs ensues further, the legs and arms begin to wear out by the time he gets to the 2nd story landing and that is when the fast twitch muscle fibers kick in.
But still, the box of books is heavy and the steps do become a bit overwhelming and in a last ditch effort, the third set or the fast twitch IIB fibers are activated and the journey upstairs is completed.

What I have written thus far is WAY over simplified and there are better and more complicated explanations that I can give but for now I just outlined the very basics.
Now the question of whether a particular muscle grouping can be built comes up, the answer is yes. Can a person who is more prone for running be a world class body builder or weight lifter? Probably not but that doesn't mean a person in the slow twitch prevalence class can't build muscle mass.
Another question might be from us older people who naturally lose fast twitch muscle fiber with age and that is, can we recover what we are losing? Yes but at the age of near 70, will I become the likes of a Steve Reeves or Reg Park? I can dream but.........probably not but I'm still trying................

We dont loose muscle fibers as we age. If not used they atrophy but with exercise and proper nutrition they can increase in size again (hypertrophy ).

I find it hard to believe that a coach didn’t know about both. When Arnold keeps taking about burnout set and shocking the muscle I believe he’s really just hitting both fibers in the sets. It’s how I like to do it most of the time. Hitting lower reps for volume and hitting the higher stuff for more reps and forcing more blood into the muscles at the same time

maj79 said:

I find it hard to believe that a coach didn’t know about both. When Arnold keeps taking about burnout set and shocking the muscle I believe he’s really just hitting both fibers in the sets. It’s how I like to do it most of the time. Hitting lower reps for volume and hitting the higher stuff for more reps and forcing more blood into the muscles at the same time

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It shouldn't be a thing of surprise that some coaches don't know the normal basis of what ordinarily they were supposed to know if they had proper training on being a fitness coach. It will surprise what we have here in my country, gym filled with non-professional who claim to be fitness coach. I have experience some that are like that, and once I get to know, I'm showing myself the exit door from the gym.