Training
to Maximize Your Muscle Fiber Types
Your muscles are made of 2 different types of
fibers. Find out what they are, what your personal
fiber make-up is and how to train for maximum
results.
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Knowing
your personal muscle fiber make-up can be an invaluable
aid when it comes to properly targeting your training
program. If you're working your muscles in the wrong
way, you'll be cheating yourself out of hard-earned
results.
Every
muscle in your body is made up of a bundle of small
fibers. In each bundle, you have two main types of fibers:
slow twitch and fast twitch. I will explain exactly
what these are in a moment. The percentages of these
different fiber types that your muscles are made of
can help you determine exactly how you should train
each particular muscle group in your body.
Slow
Twitch: These are also known as Type I or red muscle
fibers. They are responsible for long-duration, low
intensity activity such as walking or any other aerobic
activity.
Fast
Twitch: These are known as Type 2 or white muscle fibers
(divided further into A and B). They are responsible
for short-duration, high intensity activity. Type 2B
fibers are built for explosive, very short-duration
activity such as Olympic lifts. Type 2A fibers are designed
for short-to-moderate duration, moderate-to-high intensity
work, as is seen in most weight training activities.
By
looking at elite athletes in different sports, you can
see extreme examples of each make-up of muscle fiber.
At the slow twitch end is the endurance athlete, such
as the marathon runner. These athletes can have up to
80% or more of slow twitch muscle fibers in their bodies,
making them extremely efficient over long distances.
At the fast twitch end is the sprinter. World-class
sprinters can have up to 80% or more of fast twitch
muscle fibers in their body, making them extremely fast,
strong and powerful but with limited endurance.
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How
to Find Your Muscle Fiber Type:
To
find the predominant fiber type in a particular muscle
in your body, we need to test the repetition limits
of a muscle compared to its maximum strength. Keep in
mind, these limits can be altered by your training and
are, therefore, just rough estimates.
First,
determine your one rep max (known as the 1 RM) for an
isolation exercise for that muscle group, e.g. the dumbell
curl. Find the weight you can only do one rep with.
You want to use an isolation exercise because any exercise
that uses any other muscle groups will skew the results.
Once
you've figured out your one rep max, take a weight that
is 80% of it (multiply your max weight by 0.8 to get
this) and do as many reps as possible with it.
-
If you can do only 4 to 7 reps with 80% of your 1 RM,
you have mostly fast twitch fibers in that muscle. The
reason you will only be able to do 4 to 7 reps with
80% of your 1 RM is that fast twitch muscle fibers are
strong but don't have great endurance. You will be able
to lift more weight but you be able to do as many reps
with it.
-
The ability to get approximately ten reps with 80% of
your 1 RM is the typical fiber-type mix for a muscle.
This works out to about a 50/50 split between fiber
types.
-
If you can do 12 to 15 or more reps with 80% of your
1 RM, your fiber make-up is probably mostly slow
twitch fibers. Slow-twitch fibers are not as strong
but have excellent endurance. This means you won't be
able to lift quite as much but you'll be able to do
a lot more reps with it.
Repeat this procedure for each muscle group you wish
to determine a type for (it will vary from muscle to
muscle). By knowing what type of muscle fibers you have,
you can tailor your training towards developing them
to their maximum potential.
Though
there are always differences in individuals, there are
some general similarities in fiber types in muscle groups
from person to person.
For
example, in most people, the outer, visible muscle of
the calf (the gastrocnemius) is primarily made of slow
twitch fibers while the soleus (which lies underneath
the gastrocnemius) has a higher percentage of fast twitch
fibers.
Two
more examples of this similarity between people include
the abdominals and the hamstrings. These two muscle
groups are both generally made primarily of fast twitch
fibers.
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How
to Train Your Muscle Fiber Type:
When
you're training with weights, your goal is to work as
many muscle fibers as possible. Affecting more muscle
fibers means greater gains in strength and muscle mass.
If
your fibers in a particular muscle consist primarily
of slow twitch fibers, in order to affect the greatest
number of those muscle fibers, you'll need to train
that muscle with higher reps, shorter rest periods and
higher volume. This is because they take longer to fatigue,
they recover quickly and they require more work to maximize
growth.
Unfortunately,
slow twitch muscle fibers are limited in their potential
for growth so even if a muscle group is primarily slow
twitch, you should definitely include some lower rep
training to maximize the fast twitch fibers you've got
in that muscle.
If
you find you have a hard time gaining size in a particular
muscle, it could be because it has a predominance of
slow twitch muscle fibers. Higher reps (e.g. 12 to 15
reps), higher volume (more sets) and shorter rest periods
(30 seconds to a minute between sets) can help you to
maximize those muscles. This doesn't mean you should
use light weight, though. You should still strive to
use weights that are as heavy as possible that will
cause you to reach failure in those higher rep ranges.
If you don't use heavy weights, you won't give your
muscles a reason to grow.
If
your fibers in a particular muscle group consist primarily
of fast twitch muscle fibers, you're one of the lucky
ones. You'll have a much easier time building mass in
that muscle - fast twitch muscle fibers have greater
potential for size than slow twitch. The more fast twitch
fibers you've got, the greater your ultimate muscle
size can be. These muscles are most likely your strongest
and quickest to develop.
To
maximize your muscles with fast twitch fibers, you'll
need to train with low to moderate reps (e.g. 4 to 8
reps), rest periods of around 1 to 2 minutes and a moderate
training volume (too much volume will compromise recovery).
If
your muscles have a fairly even mix of fibers, you can
evenly divide your training between focusing on the
lower-rep, fast twitch fiber training and the higher-rep,
slow twitch fiber training. This will help you to develop
all the fibers in your muscles, maximizing your ultimate
development.
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Training
your muscles according to their fiber type makes sense.
It will help you to get better results from your training
by allowing you to more specifically target your training
according to the exact specifications of your muscles.
