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Written report of ST1AMINA (Group 8) PE1- ST1
John Louis Gosgolan | Pam Landayan | Zoe Jarilla | Annika Jiao
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Mervin Grajo | Luel Hernandez | Jowie Jayco | Joshua Hebron
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Joshua Mae Hormigos | Jaca Lailo
Muscle
a contractile (able or tending to shrink, tighten,
or become narrower) tissue in an animal's body
used especially for movement.
Muscles make up about 40% of total body
weight.
Facts about Muscles:
Strongest muscle? MASSETERS
(cheek muscles)
Humans are born with all of the muscle
fibers they will ever have. They DONT
grow new fibers, they just grow thicker.
Muscles CANNOT push, they can only
pull. The reason the arm can push is
muscles in the back of the arm
(TRICEPS) pulling on the elbow.
If all of the muscles in the body could all
pull in one direction, it would create a
force of 25 TONS!
Muscular Strength - a muscles capacity to exert
force against resistance.
Strength helps you lift a heavy object
with a single, powerful movement. And
to build strength, create resistance
against your muscle to the point that
you cause small tears in the fibers. As
your muscles repair these tears, they
grow larger, giving you more strength.
Muscular Endurance- the ability to perform a
specific muscular action for a prolonged period
of time.
Endurance helps you play any sport for
several hours. Prolonged use of your
muscles, rather than extreme
resistance, helps you improve your
endurance. You dont need to use
weights to improve endurance.
FOUR PROPERTIES OF MUSCLE TISSUES:
IRRITABILITY - ability to receive and
respond to stimuli via generation of an
electrical pulse which causes
contraction of the muscle cells.
EXTENSIBILITY -ability to be stretched or
extended in response to a force;
muscles usually lengthen
CONTRACTILITY -ability of a muscle to
shorten in response to a suitable stimuli
ELASTICITY -ability of a muscle fiber to
recoil and resume its resting length
*Muscle Contraction
-tightening or narrowing of a muscle
*Muscle Metabolism
-a general term used to describe the complex
biochemical reactions involved in muscle
formation and development.
ATP-PC Energy System- High Power/ Short Duration
'Adenosine-Triphosphate - Phosphocreatine system'
Composed of ATP and phosphocreatine (PC)
ATP-PC system is also known as Phosphogen system.
It is immediate and functions WITHOUT oxygen.
It allows for up to approximately 12 seconds (+ or -)
of maximum effort.
During the first few seconds of any activity, stored
ATP supplies the energy. For a few more seconds
beyond that, PC cushions the decline of ATP until
there is a shift to another energy system.
It is estimated the ATP-PC system can create energy
at approximately 36 calories minute.
Examples: a short sprint, lifting a heavy resistance
for three repetitions, or pitching a baseball.
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Anaerobic glycolysis is the transformation
of glucose to pyruvate when limited amounts
of oxygen (O2) are available.
Anaerobic glycolysis is only an effective
means of energy production during
short, intense exercise, providing
energy for a period ranging from 10
seconds to 2 minutes.
Pyruvic acid (pyruvate) supplies energy to living
cells through the citric acid cycle (also known as
the Krebs cycle) when oxygen is present
(aerobic respiration), and alternatively
ferments to produce lactate when oxygen is
lacking (fermentation).
The burning sensation in muscles during hard
exercise can be attributed to the production
of hydrogen ions during a shift to anaerobic
glycolysis as oxygen is converted to carbon
dioxide by aerobic respiration faster than the
body can replenish it. These hydrogen ions
form a part of lactic acid along with lactate. The
body falls back on this less efficient but faster
method of producing ATP under low oxygen
conditions
Adenosine Triphosphate (ATP)
It is often called the "molecular unit
of currency" of intracellular
energy transfer. ATP transports
chemical energy within cells for
metabolism.
The liver later gets rid of this excess lactate by
transforming it back into an important glycolytic
intermediate called pyruvate.
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*OXIDATIVE ENERGY SYSTEM (AEROBIC RESPIRATION)
The oxidative energy system is the primary
source of ATP at rest and during low intensity
exercise. Fats and carbs are the primary
substrates that are used. After about 90
seconds of continuous physical exertion this
energy system will kick in.
Your maximal effort was fueled initially by the
ATP-PC, but your performance declines.
Continued effort results in further decline.
Youre now entering the complex world of the
low power but longer duration oxidative
system.
Due to the time-line, the oxidative system
provides energy much more slowly than the
other two systems, but has an almost unlimited
supply. The oxidative system by itself is used
primarily during complete rest and low-intensity
activity.
Examples: Low-level manual labor on an eight-
hour work shift and everyday walk
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MUSCLE FIBERS
Type of cell found in muscle tissue.
They are long tubular cells that develop from
myoblasts to form muscles in a process knows as
myogenesis.
Fast Twitch Muscle fibers
o Uses ATP derived from glucose for fuel
o Have fewer number of mitochondria
than slow twitch, as a result, fatigue
quicker than slow twitch
o Also called white fibers because of
relatively poor blood supply. The lack of
blood results in oxygen restriction
o Much better at generating short/quick
bursts of strength or speed
o Olympic sprinters have been shown to
possess about 80 percent fast twitch
fibers
Slow Twitch muscle fibers
o Uses mixture of glucose and fat for
energy
o Have high number of mitochondria
which provide them with higher
amount of energy
o Also called red fibers because of the
proper blood supply that ensures
proper amount of oxygen which allow
them to work on a longer time
o Fire more slowly than fast twitch fibers,
but are able to contract for a longer
time before fatiguing
o Those who excel in marathons tend to
have 80 percent slow twitch fibers.
