Download Contracts to prevent

Muscular System
Muscular System
 How Muscles MoveMuscle knows no direction, it just shortens.
So when a muscle contracts one end of the joint moves
toward the other.
Muscle System
Video on muscle contraction
Watch and listen, it is complicated, but I want
you to see it and we will discuss.
Muscle Contraction Videos
https://www.youtube.com/watch?v=CepeY
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https://www.youtube.com/watch?v=gJ309
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https://www.youtube.com/watch?v=kvMFd
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Muscle System
Insertion-the more movable end of the
bone, usually more distal.
Origin-attached to the stable bone, the
more proximal end of the bone.
Exceptions to the Rule
Latissimus Dorsi-pg 137
Proximal (origin) attachment pulls toward
the distal (insertion) attachment, instead of
the more common distal attachment
pulling toward the proximal. Reversal of
muscle function.
Muscle System
So the insertion moves towards the origin.
Movable end of the bone moves towards
the more stable end of the bone.
Origin
Insertion
Muscle System
Naming Muscles-use these to find it
Location
Shape
Action
Number of heads or divisions
Attachments
Direction
size
Muscle System
Tibialis Anterior
Extensor carpi ulnaris
Serratus anterior
Triceps Brachii
Sternocleidomastoid
Go find a muscle and tell me about it. Not
one of mine. It needs to have 2 qualities
from the last list.
Muscle System
Muscle Fiber Arrangement
Parallel fibers are longer and have more range
of motion potential.
Oblique fibers are shorter but broad, so have a
greater strength potential for short range.
Muscle System
Muscle System
Parallel Muscles
Strap muscles-long and thin, fibers run the
full length of muscle. Sternocleidomastoid
Fusiform muscle-shaped like a spindle,
wide in middle tapers at ends, biceps.
Rhomboidal muscle- broad and flat all
through attachments, gluteus maximus
Triangular- flat and fan shaped, pec major.
Muscle System
Pectoralis Major
Glute Max
What is each of these??
Biceps
Muscle System
Oblique muscleUnipennate-like one
side of a feather, semimembranosus
Bipennate- like a common feather, bicep
femoris muscle
Mulipennate- tendons with oblique fibers in
between. Deltoid and subscapularis
Muscle System
Muscle System
What are these??
Characteristics of a Muscle
Stretch a muscle, and it will lengthen
(extensibility). Remove the stretch, it will
return to normal resting position
(elasticity). Stimulate a muscle, and it will
respond (irritability) by shortening
(contractility). Remove the stimulus and it
will return to its normal resting position
(elasticity).
Characteristics of muscle
Reverse contractabilityWhen the proximal end moves toward the distal
end it is a reversal of muscle action.
Examples???? Look at the bicep.
Rectus femoris
doing a leg raise
vs a sit up.
Muscle System
Tension is the force built up in a muscle.
Stretching a muscle builds up passive tension
Active tension is when the muscle is contracted.
Combine active and passive tension, and you
get total tension.
Think of kicking a soccer ball, hyperextend,
then contract quads, think of the power you
have generated.
Muscle System
The length tension relationship is the
optimal contraction of a muscle when it is
strongest.
A two joint muscle has an advantage over
a one joint muscle. Why?
Read 42-43 together
Muscle System
Active Insufficiency- muscle cannot
shorten or contract through full ROM. The
muscle will lose tension.
Passive Insufficiency- muscle cannot
lengthen or stretch through full ROM.
These are only in two joint muscles like
the hamstring and quadriceps.
Pg 43
Stretching
An agonist usually becomes actively
insufficient (cannot contract more) before
the antagonist becomes passively
insufficient (cannot be stretched anymore).
In other words if you contract your
hamstring actively to the farthest point,
then the quadriceps muscle can be
stretched farther
Stretching
To stretch a one joint muscle you must
relax the two joint muscles involved.
The soleus is a one joint muscle the
gastrocnemius is two. You must flex the
knee to stretch the soleus and dorsiflex
the ankle.
Tendon action of a muscle (Tenodesis)
Using passive insufficiency to create
tenodesis is helpful in quadriplegics.
Lets try it, read page 44 together.
Types of Muscle Contraction
Isometric Contraction-same length
Muscle contracts producing force but does not
lengthen.
Types of Muscle Contraction
 Isotonic Contraction-same tone
 Muscles contracts and the length of the muscle changes.
Concentric- shorten,
attachments move together.
accelerated act
Eccentric- lengthen,
attachments separate
decelerated act
 Examples
Types of Muscle Contraction
Isokinetic ContractionResistance to the part varies, but speed stay the
same. In isotonic the resistance remains
constant but speed varies.
Think about a biceps curl, when is it hard when is
it easy. Does resistance stay the same?
Safer way, you can stop at anytime.
Can only be done with special equipment
FUN FACT: The Cybex Orthotron was the first
machine to produce the isokinetic contraction
Roles of Muscles
Muscles assume different roles during joint
motion.
Agonist/prime mover- causes the motion
Assisting mover- depends of angle, size
leverage. Some muscles are only assisters
Antagonist- opposite motion of the agonist.
Roles of Mucles
Stabilizer is a a group that supports and
allows the agonist to work more efficiently.
Roles of Muscles
Neutralizer- Contracts to prevent the
unwanted motion.
For example the biceps muscle flexes the
elbow and supinate the forearm. If we
want just flexion the pronator teres will act
to prevent supination.
Roles of Muscles
Synergist:
A muscle that works with one or more other
muscles to enhance a particular motion.
Encompasses the role of the agonist, assisting
movers, stabilizers, and neutralizers.
Kinetic Chain
Engineering definitionKinetic Chain consists of a series of rigid
links connected in such a way as to allow
motion.
Human Body
Kinetic chain can be closed or open chain
movement that allows motion.
Kinetic Chain
Closed Chain requires that the distal
segment is fixed to something, the floor,
wall, a bar.
Open Chain is when the distal segment is
free to move and proximal segment is
stationary.
Lab time