T Nation

Fast Twitch vs. Slow Twitch how can you tell


In the recent article T-Mag talked about how to know if you are fast twitch or slow twitch.

What does this mean? How can you find out? How should one workout knowing this information?



search the forums, theres been a few posts about rep schemes that will give you some indication of your fiber makeup.


Check out this link:



The search engine would be a great place to get a lot of info on this topic. In a couple of sentences, though, here goes. Fast twitch muscles are exactly what they sound like, they provide explosive contractions useful for activities like sprinting. They have the greatest potential for growth, hence muscular sprinters, but are the first of the two types to fatigue so lower volume training is best. This was mentioned in the reader mail news blurb I think you're referring to, by the way. It also said that they have a low carb tolerance which i didn't know before. Slow twitch are the opposite. Generally, it is considered lucky to have fast twitch dominant fibers.


OK here's my scenario. I'm naturally really strong when doing a few reps. However, if I do many reps i don't have endurance. Even in college when I trained hard I worked out with a marine. He was the classic ectomorph. I was a lot stronger than he was but using the same weight let's say flyes of 50 lb dumbbells. I could only do 15 reps while he could do about 50 reps.

I've also not been good at endurance type exercises like running or cycling.

Should I train my strength which is being able to lift heavy weights?

Or should I train my weakness doing less weight but higher reps?

Does it really matter anyway? As long as I train hard like the EDT workout?

BTW, I read that body type article and I just got more confused.


no use training for endurance if you want to be strong and powerful. If you want more muscular endurance then increase reps. If you want hypertrophy/strength/power then keep the reps lower. Obviously though general hypertrophy will be slightly higher reps than training for power.


You are a lucky individual if by the sounds of it you have a dominance of fast twitch fibres. This means you should be able to hypertrophy more than someone less well endowed because type II fibres (fast twitch) have a much greater potential for size.
You haven't stated what your goals are but I assume you are trying to pack on the muscle if so just eat and train with high intensity (heavy) and low reps (6-8) for size. If you want strength and not primarily size then train heavier for 1-3 reps. Stick to large compound movements, squats, deads, bench, pull ups e.t.c.
Don't bother with endurance type training that won't give you size it will just hamper your efforts.


Try running a search for an old thread entitled "Body Fiber Composition" with my name. It was a pretty informative thread.


This could just be me, but it sounds like if you could 15 reps of a weight and he could do fifty, chances were that you weren't actually stronger than him. If what you're attempting to say is that you could still do 15 at 100 lbs, but he couldn't do any, then your point would be much easier to understand.



My goal is to get bigger and stronger. I've never had a problem gaining muscle. When I worked out hard in the past people thought I was using drugs because my strength and size went up quickly.

However, now I'm older and I want to cut my bodyfat but I'd really like to get big and strong.

I'm doing the second phase of the EDT cycle this week. That will last about 4 weeks then I'm thinking of doing the ABBH cycle. All the while I'm on the T-Dawg 2.0 diet.

I eat oats and low carb grow for breakfast. Then I train. I drink 3 servings of surge. Then I eat mainly protein the rest of the day. tuna, chicken, venison, fish, and low carb grow with EFA's mixed in. The only carbs come from non fat cottage cheese before bed but that's only like 15 grams.

Will gaining muscle size boost my RMR more than just doing strength training?

Any of you ever do the meltdown lactic acid program?

Oh yes, and regarding my marine friend he was pretty amazing. We would train to failure and at the end of our reps I was pooped and could only do about 5 reps, he did 25 or so. He never gained any size but his endurance was incredible.


I have a very low tolerance for carbs they just put the fat on my quick.


Eric Cressey--

I found the forum thread and it was very informative. I'm definately fast twitch dominant because of that 1 RM then wait 10 minutes and do a 85% I usually can only do 2 or 3. I remember this from when I trained hard in the past.

So now what do I do? Do I train any differently?

I'm responding really quickly to the EDT because of its intensity and although you perform about 60 reps in the 20 minutes they are typically 5-2 reps per set.

Is this the type of training I need to be on?


I wouldn't worry about fiber makeup all that much. Go to elitefts, click on articles then misc. articles then scroll down to the Socratic Method article by DB Hammer he talks about what he calls fiber mythology in it and how training one way or another can basically change your make up and that really it is not important...just my 2 pennies.


If you want to raise your RMR, then yes the more muscle you have regardless of strength the more calories you will require to feed them.

You respond well to EDT, then you don't have to worry much!

If you need to burn fat using cardio without sacrificing muscle then try HIIT, look up 'Running Man' article by Christian Thibadeau in issue 251.


I found the fiber make-up test on the forum.

According to the test if you can only do 4-6 reps at 80% max you are fast twitch dominant.

I chose the bench press as my test exercise. I have a 1RM of 275 pounds.

I waited 48 hours and then tested how many reps I could complete at 80% of my max (220 pounds). I could only complete 6 reps.

Has anyone else tried this test? Does this mean I should train with low reps as a rule?


Q: You once said in a seminar that you train using low reps, averaging about three reps per set, as I recall. So how come you're so freakin' big? Can you achieve hypertrophy using solely low reps? Does this have to do with your muscle fiber make-up? Are you a mutant?

A: Basically, I only began to grow once I started using very low reps for multiple sets. The key is multiple sets. I'm blessed with a higher percentage than normal of fast-twitch fibers. So, training with high reps is a waste of time for me.

It's my experience that there's an optimal number of sets per muscle group for each individual. Those who are gifted with a large number of fast-twitch motor units always do fewer reps at a given percentage of maximum. While the average trainee performs seven repetitions at 80% of his maximum, a high fast-twitch individual may do only three reps at the same percentage. Conversely, high slow-twitch individuals, who train aerobically, have been shown to do 12-37 RM at 95% of maximum, while average persons will only do two or three RM.

Since there's plenty of empirical evidence and scientific research to point out that the development of maximal strength is best accomplished by using loads representing 70-100% of one's maximum, it appears essential to determine the exact number of repetitions to be performed at this percentage range. For most fast-twitch individuals, the rep bracket optimal for strength gains falls within one to six reps, while most individuals will make gains in the 1-12 rep range. Furthermore, fast-twitch individuals would normally use more sets and short intraset rest intervals (one to three seconds between reps).

An intern of mine, John Alvino, used to get Paul Gagn? (one of the best trainers in North America) to write training programs for him. But he wasn't making much progress. After receiving Paul's blessing, John asked me to train him at a Stamford seminar. From initial testing, it became clear that John was doing too many reps. For example, he could only do two reps at 85% of max in the cervical extensors, while world champion speedskater Marc Gagnon could do in excess of 200 reps at 85% of maximum.

Now, John trains by never doing more than six reps, and his yearly average is about 3.5 reps. Well, in 12 weeks, he went from 206 pounds at 11% bodyfat to 218 pounds at 6% bodyfat. He can do close-grip bench presses at more than double his bodyweight, and his curling strength went up 50% during that time. His physique had made such dramatic changes in so short an amount of time that other seminar attendees in NYC (who were also there in Stamford) kept asking him what he'd done differently.


Lonelobo, when Walleye said he was much stronger than his friend, he probably meant a 1RM. For instance, perhaps he could do a 1RM of 100lbs, while his friend can only do 90lbs. His friend can however do more reps at roughly the same %age of max because he is more slow twitch dominant.
This "friend" must be a genetic freak however, because 50 reps with 50lbs is quite a bit of strength and work capacity for an individual, let alone an ectomorphic one. Most people can't even press that amount, let alone do flyes.


Tom hand, your post was from a QandA by Charles Poliquin. Though the idea he is trying to get across is correct, I would be skeptical of any "figures" he gives for his athletes. I have seen some of his athletes train, and they were not using near the kinds of numbers that Charles had said they did. Also keep in mind that the physical training isn't always the cause of most of the improvements in many cases. Most athletes haven't got a clue when it comes to diet, supplementation and anabolic use. All of sudden, put them on strict diets with proper anabolic enviornment to boot, and such gains are more credible. Of course, the coach(Poliquin in this case) will tell you that it was only a change in training and not mention the other goodies. Just something to keep in mind.


Muscle tissue biopsy.....only way to find out your tissue type.


Badmoon hit it right on the head. We can use every theoretical test to try and gauge what our fiber types per specific muscle group are, but the only way to know is to test each group with a biopsy. Unfortunately, I hear this isn't a very comfortable experience.