Archive: Muscle Physiology - Oh Those Crazy Muscles!
Posted on Friday, February 01 @ 12:00:00 MST
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Written by: Eric_Broser
When the average
person takes a look at a bodybuilder all he sees is a series of lumps and
bumps of varying shapes and sizes. Upon inspection he may find these odd
protrusions to be fascinating, cool, or perhaps grotesquemaybe even a
little intimidating. But little does he know how complex and intricate
all these "lumps" really are!
Let's take a look inside these lumps, see what they are made of and
what we can do to make them bigger and stronger. Ok, first let me stop
calling them lumps or bumps and refer to them more properly as skeletal
muscles, or just muscles for short.
Muscle is composed of bundles of muscle fibers or myofibers. Each
fiber is composed of myofibrils, which, in turn, are composed of
myofilaments. The myofilaments are made up of two proteins called myosin
and actin. The myosin and actin act within the smallest functional unit
of muscle, the sarcomere, to produce a contraction. It is the myosin
protein, however, which holds the key to the differences in muscle fiber
types. (Complicated lumps these muscles, aren't they!) In general, there
are four different fiber types in skeletal muscle. These four include:
Type I, also known as slow-twitch or red fibers; Type IIA, IID, and IIB,
also known collectively as fast-twitch or white fibers.
Type I are the slowest, smallest, and have the highest level of
endurance of all the fibers. Next come the Type IIA, IID, and finally the
Type IIB, which are the fastest, largest, and least endurance oriented in
the group.
As you contract a muscle, you'll recruit those muscle fibers in a
specific order. The smallest (lowest threshold) fibers, the Type I, are
recruited first. As the speed or force of contraction is increased, you
will sequentially recruit the Type IIA, IID, and IIB muscle fibers.
However, to recruit the Type IIB fibers it may take over 90% of a maximal
contraction!
All people are born with these muscle fiber types. Most muscles
contain almost an even split of slow (Type I) and fast (Type II) fibers.
There are a few exceptions, however, as the soleus muscle of the calf is
predominantly slow twitch, while the gastrocnemius muscle and the
hamstrings are predominantly fast twitch. Also, individuals on opposite
ends of the athletic spectrum like sprinters and marathon runners for
example, may possess a higher percentage of one fiber type.
So what does this mean to all of us bodybuilders? Well, in order to
obtain maximal muscle size we must regularly train all of our muscle
fibers. A combination of bodybuilding (higher and lower rep),
powerlifting, and even a little Olympic-style lifting may be best.
Bodybuilding seems to stress the Type I and IIA fibers, while the IIB
fibers may be best stimulated through powerlifting and Olympic lifting.
The IID fibers are perhaps stressed equally by all three forms of
training. I believe that the key to long term progress in bodybuilding
can be summed up by one important word: VARIATION!
Doing the same three sets of 8-12 reps over and over will help you to
a point. But after that, make a change! By selectively alternating your
training volume (total sets/reps), training intensity (weight lifted),
training techniques (forced reps, pre-exhaust, supersets, drop sets,
etc.), training tempo (rep speed), rest between sets, bodypart
arrangement, etc., you're more likely to avoid injuries and overtraining
and therefore maximize your gains. As long as the stimulus presented to
your muscles is novel and taxing, they will continue to adapt
accordingly.
Just remember that your muscle fibers are not static entitiesthey are
dynamic and malleable. Therefore you yourself should not be static-don't
do the same thing over and over and expect a different result. Don't get
stuck in just one type of training program! Be creative! Be dynamic! Your
muscles will reward you with continuous gains in size, strength, and
endurance. Now, go get to work on those "lumps!"
Muscle Mass Gaining Tips click here for free reports!
Eric Broser (gopro on the forums): Moderater of training, diet & nutrition, and
supplementation on IronMagazineForums.com, is available for online
personal training, dietary guidance, and contest prep coaching. For
details send him a e-mail
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