We'll continue in this part by
going over some basic muscle physiology and anatomy. Our muscles are
complex and fairly simple at the same time, to demonstrate this we'll
work from the outside in. The outside of our muscles are covered by a
layer of connective tissue called the Epimysium, this layer covers the
belly of the muscle and helps make up our tendons. Under the epimysium,
there is another layer of connective tissue called the Perimysium, this
layer surrounds bundles of muscle fibers. Surrounding the individual
muscles fibers is another layer called the Endomysium. All of these
layers of connective tissue help with generating muscle force.
the individual muscle fibers are what are called Myofibrils. The
myofibrils are bundles of proteins and this is where the magic happens.
There are two main proteins within in the myofibrils, myosin and actin.
These proteins are what cause muscle contraction. The myosin and actin
are organized in a way that 6 actin surround 1 myosin. With this
configuration the actin and myosin can produce force by the sliding
filament mechanism. (Don't worry we won't go into all the details)
jist of the sliding filament mechanism is that myosin and actin form a
"ratchet". The myosin attaches to the actin and pulls towards itself,
grabs another portion of the actin and pulls once again. Check out the
illustration below. The blue lines represent the actin, while the red
represent the myosin.
You're probably wondering what everything else in the illustration is and we're getting to that.......right now.
you may already know muscles are extensible and can be stretched, when
they are stretched the actin and myosin are moved apart. When this
occurs the myosin can't make as many connection with the actin and less
force is produced. On the opposite end of the spectrum, muscles can
contract and shortened in length. This is a good thing but only to a
point. As one actin fiber is pulled closer to the center of the myosin,
the other actin fiber is being pulled to the center of the myosin. (As
seen on the left of the illustration) When this happens the actin can
get in the way of each other making it difficult for the myosin to make
new connections, thus producing less force.
when fewer connections between the myosin and actin are made, the less
force is produced and the less weight can be moved.
When training in
the weight room our time and energy is precious and we want to utilize
them the best we can. By limiting full range of motion (i.e no
"squeezing" at the end of movement) during targeting exercises we can
lift a greater amount of weight.
In climbing and other athletic
activities the body is required to move throughout entire ranges of
motion. So why train the way explained above? Just like our example of
"weak links" in part 1,
we can only train as hard as our weakest link. Physiologically speaking
really long and really short muscle lengths are our weakest links and
prevent us from training to our highest potential.