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Testing 1RM And Muscle Fiber Dominance

Dear Christian,

On several occasions you spoke on this forum about testing muscle fiber dominance while performing max repetitions of 80% of your 1RM (hopefully I’m right about the percentage). I was wondering one thing: Is this something you could do immediately after you tested your 1RM? Or should you wait for another day to test this? Thanks in advance! :smiley:

Normally you would do this after your 1RM because maximum strength varies from day to day. For example if you test at 315 on day and then tested your 80% 3-4 days later, your strength might be different and 80% might really be 85 or 75%.

That having been said, it also means that you cannot do a ton of work to find your 1RM. You do your normal warm-up and progression, of course. But you cannot do 5 or so attempts close to your 1RM to get the exact number or you will create too much fatigue.

Normally you should give yourself 3 attempts (like a powerlifting meet). First one is a fairly conservative max attempt, second one is wha you think (based on your warm-up and first attempt) your 1RM should be. And the 3rd one (which you don’t have to take depending on how the 2nd went) is where you can try another heavier lift if your 2nd lift was easier than expected or go down if your 2nd was too heavy and you failed.

Then take 5 minutes of rest before testing your 80%

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Thank you so much for your response! This is truly, truly helpful.

How would you go about this when testing clients? Let’s say you have a highly trained individual vs. a non-trained individual? How true will both their results be? Though I think someone still needs to be trained to such a degree that technique is up to par to test a 1RM.

That’s a good question and it highlights the limitations of this test.

I first want to say that I rarely use that test myself. Poliquin and Fred Hatfield (Dr.Squat) popularised it. I wrote about it in my first book because I was a student of both men, but that was over 20 years ago.

The limitations are:

  1. You can’t have a beginner do a 1RM. Their technique is not solid enough and you will isk injuries. They are also not neurologically efficient and as such they will always be much worse with max effort as they are with reps. This will skew the test toward a slower twitch profile.

  2. Even with an advanced athlete (non-competitive lifter) I don’t really like testing a true 1RM, especially at the beginning of a training cycle. If you do a training cycle oriented toward strength there is a gradual work up toward 1RM work over weeks and weeks, you prepare the body for it. At the beginning of a cycle it is more potentially hazardous. You could test for a techically solid 3RM instead and add 5% to that lift to approximate the 1RM.

  3. Fiber ratio is not the only thing that determines how many reps you can get. A big one is neurological efficiency. Someone who is very neurologically efficient (rapid fiber recruitment, high firing rate, good intra/intermuscular coordination) will be proportionally better with high load/low reps. Even someone with a moderate (or even lower) ratio of FT fibers can show FT dominant results if they are very efficient. Technical efficiency in a lift also plays a role. And training experience is also important because the body becomes good at what you train: a bodybuilder who always does 8-15 reps will be better with higher reps than with low reps, a powerlifter or olympic lifter will be the opposite. Doesn’t necessarily mean that their fiber ratio is different.

  4. Muscles within an individual have different fiber ratios. Even if the test was 100% accurate, you wouldn’t get a complete profile if you only test 1 or 2 exercises. You’d have to test all the major muscles, this is just not practical unless you want to spend a whole week, or more, testing. “But I can test the bench and deadlift and get a pretty complete idea, all muscles will be covered to some extent”… sounds logical, but here is the problem. Let’s take a bench press, the triceps, pectorals, deltoids and even lats are heavily involved. NOT ALL OF THESE MUSCLES HAVE THE SAME RATIO. So even if the test was 100% reliable, it would still only represent the average of all the muscles involved.

When I teach about that test in seminars I explain all of that and mention that I haven’t really used it for over 10 years.

Now, when you use it as ONE CLUE to evaluate the athlete’s dominance it can be fine (with the right people), but it is not what I would call a “gold standard” test.

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Thank you for your extended answers!

So I guess within testing, safety plays a big role in both beginners and advanced athletes. And there a too many parameters that influence the outcome of the test.

Would you think that testing muscle fiber dominance for one particular muscle is therefore more beneficial in relation to strengthening a weak link?

When creating a program for an athlete I know that your Neurotyping system plays a huge role when it comes to sets and reps. But how would you then determine the optimal starting intensity when testing for 1RM gives too many downsides? I know some coaches would do an 8RM test and would estimate the 1RM and adjust there baseline from there… But from what you’re telling me that would give the exact same limitations (if not more!) as really testing the 1RM would give. Or would you estimate the baseline level on the training history of the client and adjust it per training session?

I’ll be honest, I don’t see a huge value in this. As soon as the load used represents 80% of what you can lift at the beginning of a rep (there is a 2-4% decrease in strength potential due to fatigue from rep to rep) you will recruit all your recruitable fibers.

So, for example even if you use a load that is 65% of your max, you will eventually recruit all your fibers when you train close to failure (by rep number 5-6 all your recruitable fibers will be used).

Fiber ratio does influence your growth potential, and could, in part, influence growth potential. But you can’t change the ratio of FT fibers that you have.

You can’t really use loading schemes to only target the ST fibers, unless you use a very light weight (under 50%) and don’t train anywhere near failure, which will not lead to a lot of hypertrophy anyway.

I don’t test. for fiber dominance at all, and it doesn’t affect my programming. It can help explain why someone will get less reps at a certain percentage or will have to use less weight when doing higher reps, but I pick reps based on the training objective, not fiber dominance of the individual.

The only reason I would see value in knowing someone’s fiber dominance is when using a percent-based periodized plan (for example building a 12 weeks progression using a certain percentage of you 1RM and precise reps with that percentage every workout). For example if you give someone who is very fast twitch dominant 5 x 5 @ 80% of this 1RM, he won’t be able to do it. If you give the same prescription to someone who is very slow twitch dominant the same plan, they will find it easy.

But since I don’t work by percentages, there is not real use for it.

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That’s really clear then, thanks! Think there are more reasons against working with percentages in than there are for working with them. Perhaps you are willing to answer my last question; Are there better methods to determine training load at baseline? Or would you just start somewhere and adjust accordingly along the way?

CT posted this at some point

If you were using percentages for a starting point I’d combine the above with the number of reps in reserve outlined for various exercises as per the Thibarmy article Should You Train to Failure to guide your initial load selection and err on underestimating rather than overestimating.

I. e. let’s say your intention is to work with 4x4-6 reps on the back squat, then opt for 75% on the bar your first session and do 4 reps for all the sets and the next session attempt to get all sixes. That’ll not crush you even if you have a bad day that day and leave room for progression.

Two weeks later you’ll be adding weight to the bar and inevitably you’ll be at a genuine 80% soon enough.


Awesome stuff, thanks!!!

Small question though… There is a small remark on the 95-100% reps that states ‘may come at a cost’. What is the exact meaning of that?

This refers to the intensiveness factor involved in cortisol production.

To recap, here is a little something from one of my articles:

The 6 Training Variables That Increase Cortisol & Adrenaline

Cortisol and adrenaline go hand in hand. Anything that’ll raise cortisol will also lead to an elevation of adrenaline. That’s why you have problems sleeping during periods of high stress.

Resistance training will increase cortisol. This is actually needed if you want to train hard. Without cortisol there’s very low adrenaline, which means lower strength, speed, endurance, and drive. But too much – especially when combined with chronically elevated levels due to a stressful life – can lead to what we call overtraining.

When it comes to training, we have six main variables that can impact cortisol and adrenaline:

1. Volume

Cortisol and adrenaline can both be used to mobilize stored energy. The more volume you do, the more energy you need. As a result, you’ll need to mobilize more energy leading to greater cortisol and adrenaline levels.

2. Intensiveness

This refers to how hard you’re pushing each set, not the actual weight lifted but how close you get to failure. The closer you get, the greater the stress response is and the more cortisol/adrenaline you produce. Going past failure with methods like rest/pause, drop sets, and the like push cortisol and adrenaline even higher.

These are the two big ones when it comes to cortisol in training. If you want to avoid high cortisol levels, both cannot be elevated at the same time. If you want to do a higher volume of work, the intensiveness has to come down – stopping each set a few reps short of failure. If you prefer to push your work sets extra hard, you’ll need to lower the volume. And there’s a middle ground where you can have both at a moderate level.

Other variables can also contribute to cortisol and adrenaline elevation, and they’re not to be overlooked.

3. Psychological Stress

This can happen if a set or max rep makes you nervous or even a bit anxious. If you need to get psyched up beforehand, or if you’re anticipating pain or discomfort before a workout, your cortisol and adrenaline levels will ramp up. This is actually your body’s way of preparing itself for battle. This is where those big weights come in, but also painful CrossFit WODs where you know you’ll hurt.

4. Neurological Demands

The harder the brain needs to work to coordinate your movements, the more it needs to be activated. And activation requires adrenaline. As such, when you use more complex movements, when you have to produce a lot of force or speed, try to learn an exercise you’ve never done before, or combine several complex exercises in a circuit, you increase nervous system activation via an increase in adrenaline (and cortisol).

5. Density

The shorter the rest intervals the more “up” your body and nervous systems need to remain, and the higher cortisol and adrenaline stay during the workout. That’s why sessions with long rest intervals are often boring to many and why adrenaline junkies tend to jump from set to set with very little rest.

6. Competition

If you want to beat a partner, your record, the clock, etc. you will increase adrenaline. Anything that gives you a sense of urgency or gets you more motivated will raise adrenaline and cortisol.


The “may come at a cost” is the greater production of cortisol and adrenaline when you push a set to failure. On machine exercises and isolation movement this is not really a problem, but on compound, free weight lifts it can do more harm than good to go to failure.


Thank you for the quick reply. At first I thought it might revolve around safety issues and injuries. So this clarifies it al. Read this article at gives lots of insight. Thanks again!!! :smiley:

Well, there is that. Not because going to failure is dangerous in itself, but on big lifts your form will degrade when you reach a point close to failure and that can lead to an increased risk of injuries.

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