This will make you enter a new phase in your fitness life

1. Image by Markus Spiske from Pixabay

2. BECOMING SUPERHUMAN
Stimulating Reps: The Ultimate
Scienti c Guide To Maximizing Muscle
Growth
This will make you enter a new phase in your tness life
Lorenz Duremdes, Polymath
Dec 15 · 14 min read
“Don’t stop when it hurts, stop when you are done.”
Table of Content
1. The Stimulating Reps Model: Recruiting High-Threshold Motor Units
2. The Stimulating Reps Model: Force-Velocity Relationship
3. How Many Stimulating Reps Do You Need For Sufficient Hypertrophy?
4. Do You Need To Go To Task Failure?
5. Multi-Joint Exercises and Stimulating Reps: Going To Task Failure Is Not
As Necessary
6. Central Nervous System Fatigue vs Peripheral Fatigue

3. 7. Keeping Central Nervous System Fatigue Low: The Do’s and Don’ts
8. Peripheral Fatigue Is Not Your Enemy: The Benefits of Peripheral Fatigue
9. Optimal Rest Periods To Maximize Hypertrophy and Strength
10. Powerbuilding: Look Strong, Be Strong
11. Passive and Active Mechanical Tension: Stretching Your Way To Muscle
Growth
12. Acknowledgements
Abstract
ant to make sure that you leave the gym knowing that your workout
will cause muscle growth?
Or maybe your muscles just don’t want to grow?
The stimulating reps model may be the answer. In fact, the model even says
that it is very well possible to have a workout causing no muscle growth
i.e. ineffective.
Lastly, the most essential thing this model also proposes is that muscle
damage does not cause hypertrophy. Instead, something else does. Read
more to find out!
W

4. So first of all, what is the stimulating reps model?
The Stimulating Reps Model: Recruiting High-
Threshold Motor Units
ssentially, this model says that, on average, the last 5 reps before task
failure are “stimulating”. That is, they are the only reps causing
sufficient skeletal muscle hypertrophy.
So why is that? First of all, we have something called Henneman’s size
principle: Low-threshold motor units are recruited before high-threshold
motor units.
Second, low-threshold motor units are characterized by recruiting a small
amount of muscle fibers, which consists mostly of type 1 slow-twitch
oxidative muscle fibers, a type of muscle fiber more effective during
endurance training rather than strength and hypertrophy training.
High-threshold motor units, on the other hand, usually recruit a way bigger
amount of muscle fibers that, instead, mostly consists of type 2a oxidative
glycolytic and type 2x glycolytic muscle fibers which, again, are muscle fiber
types that are more effective during hypertrophy and strength training.
See this for more information about the different types of muscle fibers:
E

5. Types of Muscle Fiber
Muscle ber types can be broken down into two main types:
slow twitch (Type I) muscle bers and fast twitch (Type II)…
athletics.fandom.com
Third, low-threshold motor units usually are active the whole day (e.g.
when walking), which means they probably are already close to their
“natural” max size i.e. not much hypertrophy can occur within those muscle
fibers without any ergogenic aids.
Combining all these points, we get to see that we want to recruit high-
threshold motor units as much as possible, because of their high quantity in
terms of muscle fibers and their potential to still grow. So how do we do
that?
Henneman’s size principle is, obviously, dependent on force i.e. bar weight
x bar velocity. This means that high-threshold motor units only get recruited
during high force. Again, this can be done either by a heavy bar weight,
high bar velocity, or a combination of both.
chrisabeardsley
71.2k followers
View Profile

6. View More on Instagram
616 likes
Add a comment...

7. We are not finished here, however. The stimulating reps model further says
that high force solely due to high bar velocity is ineffective.
To understand this, we have to add another element: The force-velocity
relationship.
The Stimulating Reps Model: Force-Velocity
Relationship
he force-velocity relationship essentially says that, the faster the bar
velocity, the lower the force. Why is that? Isn’t it the other way around
i.e. F = m x a? When talking about the force-velocity relationship in muscle
physiology, we actually mean something else, namely the force production
of the muscles themselves:
T
chrisabeardsley
71.2k followers
View Profile

8. Simply said, the force generated by a muscle is dependent on the total
number of actin-myosin cross-bridges attached. Second, the attachment
rate is a lot more fixed (as opposed to the detachment rate) meaning that a
View More on Instagram
847 likes
Add a comment...

9. higher bar velocity doesn’t necessarily “speed up” the formation of actin-
myosin cross-bridges.
One can, then, imagine that a higher bar velocity creates less actin-myosin
cross-bridges which, in turn, results in less force generated by the muscle.
So how does the muscle, then, “compensate” its lack of force generation
during high bar velocity? By recruiting high-threshold motor units i.e. more
and faster muscle fibers.
Again, because of the small formation of actin-myosin cross-bridges,
hypertrophy tends to be low despite recruiting high-threshold motor units.
Lastly, the force-velocity relationship also defines mechanical tension:
chrisabeardsley
71.2k followers
View Profile

10. Quick recap:
1. A too low bar weight recruits low-threshold motor units, which results in
small levels of hypertrophy;
View More on Instagram
1,317 likes
Add a comment...

11. 2. A too low bar weight and high bar velocity does recruit high-threshold
motor units, but because the formation of actin-myosin cross-bridges is
very low, hypertrophy will only occur in small levels;
3. The only option that remains which also induces sufficient
hypertrophy would be: (1) A sufficient loaded bar (i.e. high-threshold
motor units) and (2) low bar velocity i.e. high mechanical tension;
4. Each repetition that complies to point (3) is considered to be a
“stimulating repetition” or “stimulating reps”. As a side note, muscle
damage does not equate to hypertrophy.
P.S. deliberately slowing down each rep to induce high mechanical tension
doesn’t work. This is because the bar weight is too low and, therefore, low-
threshold motor units are recruited. Every repetition with a low bar velocity
due to a high bar weight, then, can only be considered to be “stimulating
reps”.
Knowing our definition of stimulating reps, how many do we have to do to
induce sufficient hypertrophy?
How Many Stimulating Reps DoYou Need For
Sufficient Hypertrophy?

12. s far as I am aware, a minimum of 15 stimulating reps is needed within a
single bout of exercise (let’s say within 4 hours).
So, just do 15 repetitions that all comply to point (3) right? Nope, it’s
not that simple.
According to research, the maximum amount of stimulating reps within a
single set is between 5 to 7 stimulating reps. For beginners, this number is
closer to 5, while for elites it’s closer to 7.
This means that the last 5 to 7 repetitions within a single set can be
considered stimulating repetitions.
Further, this also means that you need to do a minimum of 3 sets per
muscle group consisting of more than 5 reps per set (i.e. approx. 15
stimulating reps) within a single bout of exercise, preferentially 4.
Is there a maximum limit? This seems to vary from person to person.
According to this research:
" How much volume do you need to get stronger and
build muscle?
Hypertrophy No topic in the eld of exercise has been more
hotly debated over the past few decades than the amount…
www.lookgreatnaked.com
A

13. The maximum sets per week to maximize hypertrophy seems to be 30 sets
per muscle group for the upper body and 45 sets for the lower body.
Stimulating reps are easy to count in single-joint exercises such as bicep
curls: Every repetition that happens to be slow due to a lack of force
generation (rather than deliberately slowing down each rep), can be
considered a stimulating rep.
DoYou NeedTo GoToTask Failure?
ask failure simply means: The inability to continue a certain activity.
In strength training, this is due to central nervous system fatigue +
peripheral fatigue:
T
chrisabeardsley
71.2k followers
View Profile

14. Simply said, when you are doing bicep curls and do as many reps as
possible, you can be considered to have reached task-failure in the final rep.
So do we need to take each set to failure? If we take into account that the
last 5 to 7 reps within a single set can be considered “stimulating reps”, then
no, we don’t need to go to failure.
View More on Instagram
1,069 likes
Add a comment...

15. If you can do 10kg bicep curls for 10 reps before hitting task failure, but
instead only do 9 reps, you still got 4 to 6 stimulating reps.
In fact, it has been advised to not go to task-failure each time, because it
builds up long-term central nervous system fatigue, which can inhibit your
other workouts in the other days of the week:
chrisabeardsley
71.2k followers
View Profile

16. Multi-Joint Exercises and Stimulating Reps: Going
ToTask Failure Is Not As Necessary
or multi-joint exercises, however, calculating the amount of
stimulating reps is a lot more difficult. For detailed information, I
suggest listening to this podcast starting at 0:47:01:
View More on Instagram
1,090 likes
Add a comment...
F
The Stronger By Science Podcast | EP18
Effective Reps, Antioxidants, Optimal T…
1X
00:00 03:00:49

17. Simply said, this has to do with the fact that there is more than one muscle
group involved: The prime mover and the secondary movers.
When doing bench presses, for example, the prime mover can be considered
your chest muscles. The secondary movers can be considered your triceps
and shoulders, the latter mostly emphasized on the front deltoids.
In the beginning of the exercise, most of the force is generated via the prime
mover i.e. chest. As one approaches task-failure, however, force is being
carried over more and more to the secondary movers to compensate for the
lack of force generation coming from the chest muscles (prime mover).
This means that, if you want to target your chest muscles for hypertrophy,
going to task-failure is not as necessary as when targeting your biceps via
single-joint exercises.
There doesn’t seem to be a clear consensus, however, how “far away” you
can be from task failure to still induce at least a minimum of 1 stimulating
rep to the prime mover. So it is still well advised to go close to task failure,
but not as “completely” as in single-joint exercises.
For more detailed information regarding everything said in this section:
SHARE SUBSCRIBE

18. The Evidence is Lacking for "E ective Reps"
The idea that the last 5 reps before failure are "e ective
reps," and therefore the ones that REALLY matter for…
www.strongerbyscience.com
I was carelessly noting down the terms “central nervous system fatigue” and
“peripheral fatigue”. What exactly do we mean by them, and how can we
apply that information to adjust our exercises as optimally as possible
regarding stimulating repetitions?
Central Nervous System Fatigue vs Peripheral
Fatigue
entral nervous system fatigue, or central fatigue, simply means
“mental fatigue”. However, one doesn’t necessarily have or can be
aware of this central fatigue for it to impair exercise and, thus, reduce the
amount of stimulating reps per set.
Central fatigue can occur due to all kinds of things, but the main ones are:
Intra-set central fatigue and post-workout central fatigue.
Intra-set central fatigue can further occur via two main ways: High rep
range or heavy weight.
C

19. It has been proposed that high rep range mostly causes the motor cortex
itself to fatigue while heavy weight causes the motor neurons, instead, to
fatigue. Out of these two, however, the most detrimental seems to be high
rep range, which we will get to later on.
Second, post-workout central fatigue simply happens due to muscular
damage from the previous workout. The more muscle damage that workout
has caused, the more post-workout central fatigue.
Lastly, we have peripheral fatigue, which is fatigue within the muscles
themselves. Peripheral fatigue is mostly caused due to accumulation of
metabolic products such as adenosine diphosphate (broken down from
adenosine triphosphate).
So how does knowing the definitions of central and peripheral fatigue
improve our workout i.e. stimulating reps? Simply said, central fatigue
seems to lessen the maximum stimulating reps per set, while peripheral
fatigue doesn’t seem to.
Remember, stimulating reps occur within the muscles not in the brain. This,
then, is why central fatigue reduces the maximum stimulating reps per set
while peripheral fatigue doesn’t. If central fatigue is high enough, the
maximum stimulating reps per set might even be zero.

20. So how can we keep central fatigue as low as possible to ensure an effective
workout?
Keeping Central Nervous System Fatigue Low:The
Do’s and Don’ts
gain, central fatigue can occur both due to high rep range, heavy
weight, or muscular damage. Let’s take a look between high rep range
and low weight vs low rep range and heavy weight, which one is better in
keeping central fatigue as low as possible?
Simply said, low rep range and heavy weight seems to be the best option if
you want to keep central fatigue as low as possible. Why? Because the
maximum amount of stimulating reps per set is around 5 to 7, so why would
you do 30 reps anyways?
Second, central fatigue does not seem to increase at a much faster tempo
when increasing the weight and lowering the reps per set. This means that
doing 20 bicep curls with 5 kilo produces way more central fatigue than
doing 10 bicep curls with 10 kilo i.e. the ratio is about the same.
Again, the maximum stimulating reps per set is around 5 to 7, so the
optimal rep range would be 8 to 10 for hypertrophy. I personally would
advise 10 reps per set, because a lower rep range would require a much
A

21. higher weight, which could wear out the tendons a lot quicker requiring a
higher frequency of “deload weeks”. This, of course, depends on the number
of sets and workouts per week.
So we talked about the negative side-effects of central fatigue. How about
peripheral fatigue?
Peripheral Fatigue Is NotYour Enemy:The Benefits
of Peripheral Fatigue
gain, peripheral fatigue is the fatiguing of the muscles themselves
either due to accumulation of metabolic products (e.g. ADP) or due to
muscular damage from the previous workouts (this can accumulate too,
which can result in overtraining).
Only one of them is truly beneficial, namely peripheral fatigue due to
accumulation of metabolic products.
Why is peripheral fatigue due to muscular damage not beneficial? Because
it has been proposed that muscles first try to repair themselves before
undergoing hypertrophy. Again, logically, this is why you train different
body parts per day of the week.
A

22. Peripheral fatigue due to muscular damage, unlike central fatigue, can be
felt i.e. a burning sensation or pain.
So let’s go back to the beneficial version: Peripheral fatigue due to
accumulation of metabolic products. How can this benefit us in relation to
stimulating reps?
Imagine the beginning of an exercise, you are doing bicep curls for 10 reps
while feeling fresh i.e. no central or peripheral fatigue. As you progress from
rep to rep and get closer to task failure (the 10th rep), peripheral fatigue
increases more and more.
In the first few reps, the recruitment of high-threshold motor units isn’t that
necessary. As peripheral fatigue increases, however, the recruitment of
high-threshold motor units becomes more and more necessary to
compensate for the lack of force production coming from the lower-
threshold motor units.
Again, high-threshold motor units contain the fastest and highest quantity
muscle fibers maximizing hypertrophy.
Lastly, bar velocity is also very high in the beginning of the exercise, and if
we take the concept of the force-velocity relationship again, we can see how

23. the force production is rather low i.e. low mechanical tension per muscle
fiber and, therefore, low hypertrophy.
As peripheral fatigue increases, however, bar velocity slows down
increasing the mechanical tension per muscle fiber as one approaches task
failure i.e. the 10th rep.
Remember, peripheral fatigue does not decrease the amount of stimulating
reps per set, unlike central fatigue. In this example, then, we got all our 5 to
7 stimulating reps that we could get within this single set and, hence,
maximizing hypertrophy.
If peripheral fatigue is beneficial, should we do short rest periods to keep
peripheral fatigue high and also decrease the reps needed in the next sets to
approach task failure, while keeping the reps above 7 to get all the
stimulating reps? In terms of maximizing hypertrophy, it may not be that
simple in the long-term.
Optimal Rest PeriodsTo Maximize Hypertrophy and
Strength
ccording to many studies, the optimal rest period appears to be
between 2 to 3 minutes between each set of the same muscle group.
So why is that?
A

24. Their reasoning, as far as I have read, is because of the accumulation of
central nervous system fatigue. Remember how this is the “bad” type of
fatigue, decreasing the maximum amount of stimulating reps you can
perform per set:
chrisabeardsley
71.2k followers
View Profile

25. Second, it has been shown by research that central fatigue tends to decay
exponentially, rather than linearly. One can imagine, then, if most of its
decay happens at the last minute, the difference between 1 minute and 2
minutes can be pretty significant.
If you were to do 10 reps of bicep curls with only 1 minute of rest in
between, the high presence of central fatigue after the first set may only
enable you to gain 3 stimulating reps every set thereafter, instead of 5.
Another reason why longer rest periods is more beneficial, is because of its
greater strength gains (rather than just muscle size). Longer rest periods
allow you to use heavier weights, which makes you stronger more quickly,
and the greater increases of strength from workout to workout may enable
you to gain muscle size quicker, in the long-term.
View More on Instagram
1,505 likes
Add a comment...

26. One can imagine that, if you were to become twice as strong as you
currently are and also bump up your weights respectively despite your
muscle size being the same as they were before, hypertrophy gains would
come a lot more easily.
Lastly, the main difference between hypertrophy and strength (even though
hypertrophy increases strength), is that hypertrophy is simply the increase
of muscle size while strength is more due to stronger tendon strength and,
therefore, less tendon compliance:
chrisabeardsley
71.2k followers
View Profile

27. Now, if you want to maximize hypertrophy of every single muscle group via
very specific exercises, this may require you 2 hours of gym time every day
just because of waiting 3 minutes between each set. The alternative to that,
however, is powerbuilding.
Powerbuilding: Look Strong,Be Strong
ne way to not be in the gym for 2 hours every day, is to simply
alternate between more hypertrophy focused days or weeks
(“building”) and strength (“power”): Powerbuilding.
View More on Instagram
426 likes
Add a comment...
O

28. Powerbuilding is nothing more than a variant of periodization and, so far,
data says that periodization may bump up your strength gains by a few
percentages (which is a lot in the long-term):
Periodization: What the Data Say * Stronger by
Science
Before discussing periodization, you should have a thorough
understanding of what the research says. In this article…
www.strongerbyscience.com
The mesocycle between hypertrophy and strength can be as long as you
desire, you can do 3 days of strength and then 3 days of hypertrophy, or 1
week of strength and then 1 week of hypertrophy. Remember, no program
is perfect, the perfect program is whatever you can consistently follow.
As a side note, according to Layne Norton, starting your program with
strength before hypertrophy is more effective than the other way around:
The Ultimate Layne Norton PHAT Workout For Size
And Strength
If you've been struggling to make consistent progress in the
gym you need to check out Dr. Layne Norton's, PHAT…
www.anabolicbodies.com

29. On the strength days, you perform a low amount of exercises with heavy
weights and long rest periods (2 to 3 minutes). On the hypertrophy days, on
the other hand, you perform many exercises with moderate weights and
short rest periods (<1 minute).
But you just said that 2 to 3 minutes is superior for both hypertrophy and
strength gains!
Yes, if we truly want to maximize everything we can. But in all honesty, do
you want to stay in the gym for 2 hours or more every day on the
hypertrophy days?
To top this article, there is more than one way to induce hypertrophy than
just moving weights: stretching.
Passive and Active MechanicalTension: Stretching
Your WayTo Muscle Growth
tretching your muscles before a workout and after the workout (or
even between sets) may promote extra gains in hypertrophy:S
Why You Should STRETCH Between Every Set From Now On (New ScienceWhy You Should STRETCH Between Every Set From Now On (New Science……

30. Why You Should STRETCH Between Every Set From Now On (New Science Explained) on YouTube
Remember, high mechanical tension simply means high force per muscle
fiber, which also can be done by stretching these muscle fibers.
So how long should you stretch? As far as I have read, the general guideline
is to stretch for around 30 seconds per muscle group.
chrisabeardsley
71.2k followers
View Profile

31. Acknowledgements
View More on Instagram
712 likes
Add a comment...

32. I want to thank Chris Beardsley for introducing me to the concept of
mechanical tension and stimulating reps. I also highly recommend reading
his articles:
Chris Beardsley - Medium
How can we design a strength training program that will
maximize the growth of the quadriceps (commonly called…
medium.com
I want to thank Stronger by Science for introducing me to the concept of
periodization and its many benefits.
And for those interested, I also get most of my information from Jeff
Nippard and Jeff Cavaliere on YouTube.
Some rights reserved
Sports Fitness Productivity Science Health
Discover Medium
Welcome to a place where words matter.
On Medium, smart voices and original
ideas take center stage - with no ads in
sight. Watch
Make Medium yours
Follow all the topics you care about, and
we’ll deliver the best stories for you to
your homepage and inbox. Explore
Become a member
Get unlimited access to the best stories
on Medium — and support writers while
you’re at it. Just $5/month. Upgrade

33. About Help Legal