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Transcript of 03 Muscles
You have about 700 muscles...
They make up about half your weight.
They are the soft tissue that makes your body move.
Each one has its own blood vessels, nerves, and tendons.
They are everywhere — your heart, internal organs, etc.
They fall into three main categories —
(heart), and skeletal (bones).
Your skeletal muscles...
... are connected to the bones.
Muscles are meat...
Humans have white and dark meat too...
muscles keep working for hours, but are not particularly strong or fast.
muscles provide quick bursts of power, but tire easily.
Muscle is dense — about 1.06 kg/liter...
It is more dense than water (1.00 kg/liter)*...
Muscle fibers work in groups...
Muscle fibers (myocytes) are bundled together in fascicles.
Your muscles are usually relaxed....
The three easiest pairs...
And the muscles in the torso...
Let's start with the gluteal muscles in the butt...
And the muscles on the sides...
You know about your rectus abdominus muscles (abs)...
And the neck and shoulders...
You have pectorals (pecs) across your chest...
... are clearly defined beneath the skin.
... have names that make sense to us.
... are the ones that we
... can actively be controlled with our minds.
Dark meat is in the legs — the part of the bird that is used when chickens scurry around the barnyard.
White meat is in the breast — the part of the bird that is used only when chickens fly.
Consider two athletes: a marathoner and a sprinter.
One has more developed slow-twitch muscles and the other has more developed fast-twitch muscles.
... and much more dense than adipose tissue (Outstanding Leader has a density of about 0.92 kg/liter).
Skeletal muscles contract in groups. The groups are arranged to make a bone move.
The biceps and the triceps move the lower arm...
The gastrocnemius (calf muscle) and soleus (shin muscle) move the foot up and down...
And the hamstrings (three muscles in the back of the thigh) and the quadriceps (four muscles in the front of the thigh) swing the lower leg backward and forward...
are muscles that begin an action and
are muscles that end an action.
Followed by the
in the lower back...
And the lattisimus dorsi (lats) in the central back...
And you have external
that twist your
Tucked under your deltoids (delts) capping the shoulder...
And opposed by your trapezius covering your rhomboids.
Don't believe everything you read in
Tell them Josh sent you...
* 62.4 lb/ft3 = 8.34 lb/gallon
Time out for
— the Roman word meaning bundle. The fasces is an ax surrounded by bundled sticks of wood. The bundle is said to be stronger than any individual stick. This concept became a symbol for the
party in Italy during WW2.
Fascicles are bundled together in a "muscle" unit.
The muscle is attached to the bone (or to other muscles) by a
But when you use one, you are telling it to
Paired skeletal muscles have a name...
Everything in moderation....
The biceps and the triceps work as a pair.
Take your forearm, for example...
And when you contract your triceps, your arm moves downward — away from the shoulder.
When you contract your biceps, your arm moves upward — toward your shoulder.