Download Chapter 2 Skeletal Muscles

Skeletal Muscles
• Responsible for movement of body and
all of its joints
• Muscle contraction produces force that
causes joint movement
• Muscles also provide
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Neuromuscular Fundamentals
– protection
– posture and support
– produce a major portion of total body heat
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R.T. Floyd, EdD, ATC, CSCS
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Skeletal Muscles
Neuromuscular Fundamentals
2-2
Skeletal Muscles
• Over 600 skeletal muscles comprise
approximately 40 to 50% of body weight
• 215 pairs of skeletal muscles usually
work in cooperation with each other to
perform opposite actions at the joints
which they cross
• Aggregate muscle action - muscles work
in groups rather than independently to
achieve a given joint motion
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Muscle Nomenclature
• Location - rectus femoris, palmaris
longus
• Points of attachment - coracobrachialis,
extensor hallucis longus, flexor
digitorum longus
• Action - erector spinae, supinator,
extensor digiti minimi
• Action & shape – pronator quadratus
– visual appearance
– anatomical location
– function
Shape – deltoid, rhomboid
Size – gluteus maximus, teres minor
Number of divisions – triceps brachii
Direction of its fibers – external oblique
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Muscle Nomenclature
• Muscles are usually named due to
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•
•
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Muscle Nomenclature
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•
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Muscle Nomenclature
Action & size – adductor magnus
Shape & location – serratus anterior
Location & attachment – brachioradialis
Location & number of divisions – biceps
femoris
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• Muscle grouping & naming
– Shape – Hamstrings
– Number of divisions – Quadriceps, Triceps
Surae
– Location – Peroneals, Abdominal,
Shoulder Girdle
– Action – Hip Flexors, Rotator Cuff
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Shape of Muscles & Fiber Arrangement
– factor in muscle’s ability to exert force
– greater cross section diameter = greater
force exertion
• Muscle’s ability to shorten
– longer muscles can shorten through a
greater range
– more effective in moving joints through
large ranges of motion
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Shape of Muscles & Fiber Arrangement
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• Categorized into
following shapes
– parallel & pennate
– each is further subdivided according to
shape
–
–
–
–
–
• Parallel muscles
– fibers arranged parallel to length of muscle
– produce a greater range of movement than
similar sized muscles with pennate
arrangement
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Neuromuscular Fundamentals
Fiber Arrangement - Parallel
• 2 major types of fiber arrangements
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• Cross section diameter
– muscle’s ability to exert force
– range through which it can effectively exert
force onto the bones
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Neuromuscular Fundamentals
Shape of Muscles & Fiber Arrangement
• Muscles have different shapes & fiber
arrangement
• Shape & fiber arrangement affects
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Flat
Fusiform
Strap
Radiate
Sphincter or
circular
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Fiber Arrangement - Parallel
Fiber Arrangement - Parallel
• Fusiform muscles
• Flat muscles
– spindle-shaped with a central belly that
tapers to tendons on each end
– allows them to focus their power onto
small, bony targets
– Ex. brachialis, biceps brachii
– usually thin & broad, originating from
broad, fibrous, sheet-like aponeuroses
– allows them to spread their forces over
a broad area
– Ex. rectus abdominus & external
oblique
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Fiber Arrangement - Parallel
– also described sometimes as being
triangular, fan-shaped or convergent
– have combined arrangement of flat &
fusiform
– originate on broad aponeuroses &
converge onto a tendon
– Ex. pectoralis major, trapezius
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Fiber Arrangement - Parallel
Neuromuscular Fundamentals
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• Pennate muscles
– technically endless strap muscles
– surround openings & function to
close them upon contraction
– Ex. orbicularis oris surrounding the
mouth
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Fiber Arrangement - Pennate
• Sphincter or circular muscles
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• Radiate muscles
– more uniform in diameter with
essentially all fibers arranged in a
long parallel manner
– enables a focusing of power onto
small, bony targets
– Ex. sartorius
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Fiber Arrangement - Parallel
• Strap muscles
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– have shorter fibers
– arranged obliquely to their tendons in a
manner similar to a feather
– arrangement increases the cross sectional
area of the muscle, thereby increasing the
power
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Fiber Arrangement - Pennate
Fiber Arrangement - Pennate
• Categorized based upon the exact
arrangement between fibers & tendon
– Unipennate muscles
• fibers run obliquely from a tendon
on one side only
• Ex. biceps femoris, extensor
digitorum longus, tibialis posterior
– Unipennate
– Bipennate
– Multipennate
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Fiber Arrangement - Pennate
• have several tendons with fibers
running diagonally between them
• Ex. deltoid
– Bipennate & unipennate produce
strongest contraction
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Muscle Tissue Properties
Muscle Tissue Properties
• Skeletal muscle tissue has 4 properties
related to its ability to produce force &
movement about joints
• Irritability or Excitability - property of
muscle being sensitive or responsive to
chemical, electrical, or mechanical
stimuli
• Contractility - ability of muscle to
contract & develop tension or internal
force against resistance when
stimulated
– Irritability or excitability
– Contractility
– Extensibility
– Elasticity
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– Multipennate muscles
• fibers run obliquely on both sides
from a central tendon
• Ex. rectus femoris, flexor hallucis
longus
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Neuromuscular Fundamentals
Fiber Arrangement - Pennate
– Bipennate muscle
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Muscle Tissue Properties
Muscle Terminology
• Extensibility - ability of muscle to be
passively stretched beyond it normal
resting length
• Elasticity - ability of muscle to return to
its original length following stretching
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• Intrinsic - pertaining usually
to muscles within or
belonging solely to body part
upon which they act
– Ex. small intrinsic muscles
found entirely within the hand
or feet
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Muscle Terminology
• Action - specific movement of joint
resulting from a concentric contraction
of a muscle which crosses joint
– Ex. biceps brachii has the action of flexion
at elbow
– Ex. forearm muscles that attach
proximally on distal humerus and
insert on fingers
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• Actions are usually caused by a group
of muscles working together
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Muscle Terminology
Muscle Terminology
• Any of the muscles in the group can be
said to cause the action, even though it
is usually an effort of the entire group
• A muscle may cause more than one
action either at the same joint or a
different joint depending upon the
characteristics of the joints crossed by
the muscle
• Innervation - segment of nervous
system defined as being responsible for
providing a stimulus to muscle fibers
within a specific muscle or portion of a
muscle
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Muscle Terminology
• Extrinsic - pertaining usually to
muscles that arise or originate
outside of (proximal to) body part
upon which they act
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– A muscle may be innervated by more than
one nerve & a particular nerve may
innervate more than one muscle or portion
of a muscle
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Muscle Terminology
Muscle Terminology
• Tendon - Fibrous connective tissue, often
cordlike in appearance, that connects
muscles to bones and other structures
• Amplitude
– range of muscle fiber length between
maximal & minimal lengthening
– Two muscles may share a common tendon
• Ex. Achilles tendon of gastrocnemius & soleus
muscles
– A muscle may have multiple tendons connecting it
to one or more bones
• Ex. three proximal attachments of triceps
brachii
• Gaster (belly or body)
– central, fleshy portion of the muscle that
generally increases in diameter as the
muscle contracts
– the contractile portion of muscle
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Muscle Terminology
• Fascia
– A sheet or band of fibrous connective
tissue that envelopes, separates, or binds
together parts of the body such as
muscles, organs, and other soft tissue
structures of the body
– In certain places throughout the body, such
as around joints like the wrist & ankle,
fascial tissue forms a retinaculum to retain
tendons close to the body
– A tendinous expansion of dense fibrous
connective tissue that is sheet- or
ribbonlike in appearance and resembles a
flattened tendon
– Aponeuroses serve as a fascia to bind
muscles together or as a means of
connecting muscle to bone
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Muscle Terminology
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Muscle Terminology
• Origin
• Insertion
– Structurally, the proximal attachment of a
muscle or the part that attaches closest to
the midline or center of the body
– Functionally & historically, the least
movable part or attachment of the muscle
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Muscle Terminology
• Aponeurosis
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– Structurally, the distal attachment or the
part that attaches farthest from the midline
or center of the body
– Functionally & historically, the most
movable part is generally considered the
insertion
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Muscle Terminology
Muscle Terminology
• Ex. biceps curl exercise
• When a particular muscle contracts
– biceps brachii muscle in arm has its origin
(least movable bone) on scapula and its
insertion (most movable bone) on radius
– it tends to pull both ends toward the gaster
– if neither of the bones to which a muscle is
attached are stabilized then both bones
move toward each other upon contraction
– more commonly one bone is more
stabilized by a variety of factors and the
less stabilized bone usually moves toward
the more stabilized bone upon contraction
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• In some movements this process can be
reversed, Ex. pull-up
– radius is relatively stable & scapula moves up
– biceps brachii is an extrinsic muscle of elbow
– brachialis is intrinsic to the elbow
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Neuromuscular Fundamentals
Types of muscle contraction
Types of muscle contraction
• Contraction - when tension is developed
in a muscle as a result of a stimulus
• Muscle “contraction” term may be
confusing, because in some contractions
the muscle does not shorten in length
• As a result, it has become increasingly
common to refer to the various types of
muscle contractions as muscle actions
instead
• Muscle contractions can be used to
cause, control, or prevent joint movement
or
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– to initiate or accelerate movement of a body
segment
– to slow down or decelerate movement of a
body segment
– to prevent movement of a body segment by
external forces
• All muscle contractions are either
isometric or isotonic
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Types of muscle contraction
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Types of muscle contraction
Muscle Contraction
• Isometric contraction
– tension is developed within
muscle but joint angles remain
constant
– static contractions
– significant amount of tension
may be developed in muscle to
maintain joint angle in relatively
static or stable position
– may be used to prevent a body
segment from being moved by
external forces
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Neuromuscular Fundamentals
(under tension)
Isometric
Isotonic
Concentric
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Eccentric
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Types of muscle contraction
Types of muscle contraction
• Isotonic contractions involve muscle
developing tension to either cause or
control joint movement
• Movement may occur at any given joint
without any muscle contraction
whatsoever
– dynamic contractions
– the varying degrees of tension in muscles
result in joint angles changing
– referred to as passive
– solely due to external forces such as those
applied by another person, object, or
resistance or the force of gravity in the
presence of muscle relaxation
• Isotonic contractions are either
concentric or eccentric on basis of
whether shortening or lengthening
occurs
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Types of muscle contraction
– muscle develops tension as it
shortens
– occurs when muscle develops
enough force to overcome
applied resistance
– causes movement against
gravity or resistance
– described as being a positive
contraction
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Types of muscle contraction
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• Eccentric contraction (muscle
action)
– force developed by the muscle
is greater than that of the
resistance
– results in joint angle changing
in the direction of the applied
muscle force
– causes body part to move
against gravity or external
forces
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Types of muscle contraction
• Concentric contraction
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• Concentric contraction
• Eccentric contractions
involve the muscle
lengthening under
tension
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Neuromuscular Fundamentals
Types of muscle contraction
• Concentric contractions
involve muscle
developing tension as it
shortens
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– muscle lengthens under tension
– occurs when muscle gradually
lessens in tension to control the
descent of resistance
– weight or resistance overcomes
muscle contraction but not to the
point that muscle cannot control
descending movement
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Types of muscle contraction
Types of muscle contraction
• Eccentric contraction (muscle
action)
• Eccentric contraction (muscle
action)
– controls movement with gravity
or resistance
– described as a negative
contraction
– force developed by the muscle
is less than that of the
resistance
– results in the joint angle
changing in the direction of the
resistance or external force
– controls body part to allow
movement with gravity or
external forces (resistance)
– used to decelerate body
segment movement
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Neuromuscular Fundamentals
Determining if a muscle (or muscle group) is contracting and, if so, how?
Types of muscle contraction
Is Movement Occurring?
Yes
No
Then is an external force (gravity, machine, inertia, etc.) causing the movement?
• Eccentric contraction (muscle action)
– Some refer to this as a muscle action
instead of a contraction since the muscle is
lengthening as opposed to shortening
Yes
No
Is the joint moving Faster,
Slower, or at the Same
Speed that the external force
would normally cause it to
move?
Then internal force (muscle contraction) must be
causing the movement which means the agonist
muscle group is performing a concentric contraction to
cause movement in the direction in which it is occurring.
Shortening
Then the contraction
is concentric
because the
movement is being
accelerated (caused
or enhanced) by the
muscles that cause
movement (agonists)
in the same direction
as the occurring
movement.
Contracting
muscle is
shortening
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• Isokinetics - a type of dynamic exercise
using concentric and/or eccentric muscle
contractions
Slower
Then the contraction
is eccentric because
the movement is
being decelerated
(controlled) by the
muscles that oppose
movement
(antagonists) in the
direction of the
occurring movement.
Then there is no
appreciable
active contraction
in either the
shortening or
lengthening muscle
groups. All
movement is
passive and
caused by the
external force(s).
If the sum of gravity &
external forces were to
cause the joint to move
into flexion then the
extensors must be
contracting isometrically
to maintain the position.
If the sum of gravity &
external forces were to
cause the joint to move
into extension then the
flexors must be
contracting isometrically
to maintain the position.
Respectively substitute
adduction & abductors or
internal rotation &
external rotators
Respectively substitute
abduction & adductors or
external rotation &
internal rotators
Contracting
muscle is
lengthening
Contracting muscle is neither
shortening or lengthening
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• Agonist muscles
– cause joint motion through a specified
plane of motion when contracting
concentrically
– known as primary or prime movers, or
muscles most involved
– speed (or velocity) of movement is constant
– muscular contraction (ideally maximum
contraction) occurs throughout movement
– not another type of contraction, as some
have described
– Ex. Biodex, Cybex, Lido
Neuromuscular Fundamentals
Yes
Then no contraction is needed
in any of the muscles to maintain
the position, but muscle could be
unecessarily contracting
isometrically.
Role of Muscles
Types of muscle contraction
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No
Then there must be internal
force generated by an
isometric muscle contraction
to maintain the current position
of the joint.
Same Speed
Faster
• Various exercises may use any one or
all of these contraction types for muscle
development
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Shortening
Is the joint fully supported in its current
position by external means?
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Role of Muscles
Role of Muscles
• Agonist muscles
• Antagonist muscles
– Primary or prime movers, or muscles most
involved
–
–
–
–
located on opposite side of joint from agonist
have the opposite concentric action
known as contralateral muscles
work in cooperation with agonist muscles by
relaxing & allowing movement
– when contracting concentrically perform the
opposite joint motion of agonist
– Ex. quadriceps muscles are antagonists to
hamstrings in knee flexion
• Some agonist muscles, because of their relative location,
size, length, or force generation capacity, are able to
contribute significantly more to the joint movement than
other agonists
– Assisters or assistant movers
• Agonist muscles that contribute significantly less to the
joint motion
– Consensus among all authorities regarding which
muscles are primary movers and which are weak
assistants does not exist in every case
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Role of Muscles
• Synergist
– surround joint or body part
– contract to fixate or stabilize the area to enable
another limb or body segment to exert force &
move
– known as fixators
– essential in establishing a relatively firm base for
the more distal joints to work from when carrying
out movements
– Ex. biceps curl
– assist in action of agonists
– not necessarily prime movers for the action
– known as guiding muscles
– assist in refined movement & rule out
undesired motions
– helping synergists & true synergists
• muscles of scapula & glenohumeral joint must contract in
order to maintain shoulder complex & humerus in a
relatively static position so that the biceps brachii can
more effectively perform curls
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• True synergists
– have an action in common but also have actions
antagonistic to each other
– help another muscle move the joint in the desired
manner and simultaneously prevent undesired
actions
– Ex. Anterior & posterior deltoid
– contract to prevent an undesired joint action of
agonist and have no direct effect on agonist action
– Ex. Finger flexors are provided true synergy by
wrist extensors when grasping an object
• Finger flexors originating on forearm and humerus are
agonists in both wrist flexion & finger flexion
• Wrist extensors contract to prevent wrist flexion by finger
flexors
• This allows finger flexors to utilize more of their force
flexing the fingers
• Anterior deltoid acts as an agonist in glenohumeral
flexion, while posterior deltoid acts as an extensor
• Helping each other, they work in synergy with middle
deltoid to accomplish abduction
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Role of Muscles
• Helping synergists
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Role of Muscles
• Stabilizers
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Role of Muscles
Role of Muscles
• Force Couples
• Neutralizers
– Force couples occur when two or
more forces are pulling in different
directions on an object, causing
the object to rotate about its axis
– Coupling of muscular forces
together in the body can result in
a more efficient movement
– counteract or neutralize the action of another
muscle to prevent undesirable movements such
as inappropriate muscle substitutions
– referred to as neutralizing
– contract to resist specific actions of other muscles
– Ex. when only supination action of biceps brachii
is desired, the triceps brachii contracts to
neutralize the flexion action of the biceps brachii
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Tying Roles of Muscles All Together
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Tying Roles of Muscles All Together
• Muscles with multiple agonist actions
• Two muscles may work in synergy by
counteracting their opposing actions to
accomplish a common action
– attempt to perform all of their actions when
contracting
– cannot determine which actions are appropriate
for the task at hand
• Actions actually performed depend upon
several factors
–
–
–
–
the motor units activated
joint position
muscle length
relative contraction or relaxation of other muscles
acting on the joint
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Tying Roles of Muscles All Together
Tying Roles of Muscles All Together
• Example of muscle roles in kicking a ball
• Example of muscle roles in kicking a ball
– Muscles primarily responsible for hip flexion
& knee extension are agonists
– Hamstrings are antagonistic & relax to allow
the kick to occur
– Preciseness of the kick depends upon the
involvement of many other muscles
– The lower extremity route & subsequent
angle at the point of contact (during the
forward swing) depend upon a certain
amount of relative contraction or relaxation
in the hip abductors, adductors, internal
rotators & external rotators (acting in a
synergistic fashion to guide lower extremity
precisely)
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Tying Roles of Muscles All Together
Tying Roles of Muscles All Together
• Example of muscle roles in kicking a ball
• Example of muscle roles in kicking a ball
– These synergistic muscles are not primarily
responsible for knee extension & hip flexion
but contribute to accuracy of the total
movement
– They assist in refining the kick & preventing
extraneous motions
– These synergistic muscles in contralateral
hip & pelvic area must be under relative
tension to help fixate or stabilize the pelvis
on that side to provide a relatively stable
base for the hip flexors on the involved side
to contract against
– Pectineus & tensor fascia latae are
adductors and abductors, respectively, in
addition to flexors
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Tying Roles of Muscles All Together
– Ex. elbow extensors are antagonistic to
elbow flexors
– Elbow movement in returning to hanging
position after chinning is extension, but
triceps & anconeus are not being
strengthened
– Elbow joint flexors contract concentrically
followed by eccentric contraction of same
muscles
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Tying Roles of Muscles All Together
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• A muscle group described to perform a
given function can contract to control
the exact opposite motion
– Specific exercises are needed for each
antagonistic muscle group
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Reversal of Muscle Function
• Antagonistic muscles produce actions
opposite those of the agonist
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• Antagonistic muscles produce actions
opposite those of the agonist
– Abduction & adduction actions are
neutralized by each other
– Common action of the two muscles results
in hip flexion
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Tying Roles of Muscles All Together
• Example of muscle roles in kicking a ball
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Determination of Muscle Action
Determination of Muscle Action
• Palpation
• Variety of methods
– using to sense of touch to feel or examine
a muscle as it is contracted
– limited to superficial muscles
– helpful in furthering one’s understanding of
joint mechanics
– consideration of anatomical lines of pull
– anatomical dissection
– palpation
– models
– electromyography
– electrical stimulation
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• Long rubber bands may be used as
models to simulate muscle lengthening
or shortening as joints move through
ranges of motion
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Determination of Muscle Action
– reverse approach of electromyography
– use electricity to cause muscle activity
– surface electrodes are placed over muscle
& the stimulator causes muscle to contract
– joint actions may then be observed to see
the effect of the muscle’s contraction
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Lines of Pull
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Consider the following
1. Exact locations of bony
landmarks to which muscles
attach proximally & distally
and their relationship to joints
2. Planes of motion through
which a joint is capable of
moving
3. Muscle’s relationship or line of
pull relative to the joint’s axes
of rotation
Neuromuscular Fundamentals
Neuromuscular Fundamentals
Lines of Pull
Consider the following
Manual of
Structural Kinesiology
2-74
• Electrical muscle stimulation
– utilizes either surface electrodes which are
placed over muscle or fine wire/needle
electrodes placed into muscle
– as subject moves joint & contracts
muscles, EMG unit detects action
potentials of muscles and provides an
electronic readout of contraction intensity &
duration
– most accurate way of detecting presence &
extent of muscle activity
Neuromuscular Fundamentals
Neuromuscular Fundamentals
Determination of Muscle Action
• Electromyography (EMG)
Manual of
Structural Kinesiology
Manual of
Structural Kinesiology
4. As a joint moves the line of pull may change
& result in muscle having a different or
opposite action than in the original position
5. Potential effect of other muscles’ relative
contraction or relaxation on a particular
muscle’s ability to cause motion
6. Effect of a muscle’s relative length on its
ability to generate force
2-77
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
2-78
13
Lines of Pull
Neural control of voluntary movement
Consider the following
• Muscle contraction result from
stimulation by the nervous system
• Every muscle fiber is innervated by a
somatic motor neuron which, when an
appropriate stimulus is provided, results
in a muscle contraction
7. Effect of the position of other joints on the
ability of a biarticular or multiarticular
muscle to generate force or allow
lengthening
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Structural Kinesiology
Neuromuscular Fundamentals
2-79
Neural control of voluntary movement
• The stimulus may be processed in varying
degrees at different levels of the central
nervous system (CNS) which may be divided
into five levels of control
– cerebral cortex
– basal ganglia
– cerebellum
– brain stem
– spinal cord
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Structural Kinesiology
Neuromuscular Fundamentals
2-80
Neural control of voluntary movement
– highest level of control
– provides for the creation of voluntary
movement as aggregate muscle action, but
not as specific muscle activity
– interpretes sensory stimuli from body to a
degree for determine of needed responses
2-81
• Basal ganglia
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
2-82
Neural control of voluntary movement
• Cerebellum
– the next lower level
– controls maintenance of postures &
equilibrium
– controls learned movements such as
driving a car
– controls sensory integration for balance &
rhythmic activities
Neuromuscular Fundamentals
Neuromuscular Fundamentals
• Cerebral cortex
Neural control of voluntary movement
Manual of
Structural Kinesiology
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Structural Kinesiology
– a major integrator of sensory impulses
– provides feedback relative to motion
– controls timing & intensity of muscle activity
to assist in the refinement of movements
2-83
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Structural Kinesiology
Neuromuscular Fundamentals
2-84
14
Neural control of voluntary movement
• Brain stem
• Spinal cord
– integrates all central nervous system
activity through excitation & inhibition of
desired neuromuscular functions
– functions in arousal or maintaining a
wakeful state
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
– common pathway between CNS & PNS
– has the most specific control
– integrates various simple & complex spinal
reflexes
– integrates cortical & basal ganglia activity
with various classifications of spinal
reflexes
2-85
Neural control of voluntary movement
• Functionally, PNS is divided into
sensory & motor divisions
Neuromuscular Fundamentals
2-87
• PNS - 2 groups of
nerves of primary
importance
2-86
Neural control of voluntary movement
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Structural Kinesiology
Neuromuscular Fundamentals
2-88
Neural control of voluntary movement
• Cranial nerves
– 12 pair originating from undersurface of
brain & exiting from the cranial cavity
through skull openings
– numbered for the order in which they
emerge from anterior to posterior
– named in relation to their function or
distribution
– Cranial nerves
– Spinal nerves
Neuromuscular Fundamentals
Neuromuscular Fundamentals
– voluntary or somatic nerves which are
under conscious control & carry impulses
to skeletal muscles
– involuntary or visceral nerves, referred to
as the autonomic nervous system (ANS)
which carry impulses to the heart, smooth
muscles, and glands
Neural control of voluntary movement
Manual of
Structural Kinesiology
Manual of
Structural Kinesiology
• Efferent nerves further subdivided into
– Sensory or afferent nerves bring impulses
from receptors in skin, joints, muscles, &
other peripheral aspects of body to CNS
– Motor or efferent nerves carry impulses to
outlying regions of body from the CNS
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Structural Kinesiology
Neural control of voluntary movement
2-89
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Structural Kinesiology
Neuromuscular Fundamentals
2-90
15
Neural control of voluntary movement
I. Olfactory
• Cranial nerves
– smell
– identifying familiar odors
– I, II, & VIII are sensory
– III, IV, VI, XI, & XII, except for some
proprioceptive function, are primarily motor
– V, VII, IX, & X have mixed functions - both
motor & sensory
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
II. Optic
– sight or Vision
– visual acuity
2-91
Neural control of voluntary movement
III. Oculomotor
– superior oblique muscle of eyeball
– downward and lateral gaze
2-93
Neural control of voluntary movement
VI. Abducens
2-92
Neural control of voluntary movement
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
2-94
Neural control of voluntary movement
VIII. Vestibulocochlear (Acoustic Nerve)
– lateral rectus muscle of eyeball
– lateral gaze
– hearing, balance/equilibrium
– detecting presence of sounds, balance &
coordination
VII. Facial
IX. Glossopharyngeal
– taste
– touch, pain
– facial muscles
– lateral gaze, facial expressions, identifying
familiar tastes with front of tongue
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
– touch, pain
– skin of face, scalp behind the ears, mucous
membranes of nose, sinuses, mouth,
anterior tongue
– muscles of mastication
– corneal reflex, facial sensation, teeth
clenching; chewing
IV. Trochlear
Neuromuscular Fundamentals
Manual of
Structural Kinesiology
V. Trigeminal
– levator of eyelid; superior, medial, and
inferior recti; inferior oblique muscles of
eyeball
– upward, downward, & medial gaze,
reaction to light
Manual of
Structural Kinesiology
Neural control of voluntary movement
Neuromuscular Fundamentals
– touch, pain
– taste
– muscles of pharynx
– gag reflex, swallowing
2-95
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Structural Kinesiology
Neuromuscular Fundamentals
2-96
16
Neural control of voluntary movement
X. Vagus
Neural control of voluntary movement
XII. Hypoglossal
– touch, pain
– muscles of palate, pharynx, & larynx
– gag reflex, swallowing, speech
– muscles of tongue
– tongue movements
XI. Accessory
– sternocleidomastoid & trapezius muscle
– shoulder shrugging, head movement
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
2-97
Neural control of voluntary movement
• Spinal nerves
Neuromuscular Fundamentals
Neural control of voluntary movement
•
•
•
•
•
2-99
• Cervical nerves 1 through 4
Manual of
Structural Kinesiology
8 cervical nerves
12 thoracic nerves
5 lumbar nerves
5 sacral
1 coccygeal nerve
Neuromuscular Fundamentals
2-100
Neural control of voluntary movement
• Cervical nerves 5 - 8 & thoracic nerve 1
– form the cervical plexus
– generally responsible for sensation from
upper part of shoulders to back of head
and front of neck
– supplies motor innervation to several
muscles of the neck
Neuromuscular Fundamentals
2-98
– provide both motor & sensory function for
their respective portions of body
– named for the location from which they exit
vertebral column
– from each of side of spinal column
Neural control of voluntary movement
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
• Spinal nerves
– 31 pairs originate from the spinal cord
– pass through openings between the
vertebrae on each side
– from here certain spinal nerves form
different plexuses
– eventually become peripheral nerve
braches supplying specific anatomical
locations while others run directly to
specific anatomical locations
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Structural Kinesiology
Manual of
Structural Kinesiology
– form the brachial plexus
– supplies motor & sensory function to the
upper extremity and most of the scapula
2-101
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Structural Kinesiology
Neuromuscular Fundamentals
2-102
17
Neural control of voluntary movement
• Sensory function of spinal nerves is to
provide feedback to CNS regarding
skin sensation
• Dermatome - defined area of skin
supplied by a specific spinal nerve
• Myotome - muscle or group of
muscles supplied by a specific spinal
nerve
• Certain spinal nerves are also
responsible for reflexes
• Thoracic nerves 2-12 run directly to
specific anatomical locations in thorax
• All lumbar, sacral, & coccygeal nerves
form the lumbosacral plexus which
supplies sensation & motor function to
lower trunk, entire lower extremity &
perineum
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Structural Kinesiology
Neuromuscular Fundamentals
2-103
Neural control of voluntary movement
• Neurons (nerve cells) - basic functional
units of nervous system responsible for
generating & transmitting impulses and
consist of
Neuromuscular Fundamentals
2-105
• Sensory neurons transmit impulses to
spinal cord & brain from all parts of
body
• Motor neurons transmit impulses away
from the brain & spinal cord to muscle &
glandular tissue
• Interneurons are central or connecting
neurons that conduct impulses from
sensory neurons to motor neurons
Neuromuscular Fundamentals
Neuromuscular Fundamentals
2-104
Neural control of voluntary movement
– Motor neurons
– Sensory neurons
– Interneurons
Neural control of voluntary movement
Manual of
Structural Kinesiology
Manual of
Structural Kinesiology
• Neurons are classified as
one of three types according
to the direction in which they
transmit impulses
– a neuron cell body
– one or more branching projections known
as dendrites which transmit impulses to
neuron & cell body
– axon - an elongated projection that
transmits impulses away from neuron cell
bodies
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Structural Kinesiology
Neural control of voluntary movement
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Structural Kinesiology
Neuromuscular Fundamentals
2-106
Proprioception & Kinesthesis
• Activity performance is significantly
dependent upon neurological feedback
from the body
• We use various senses to determine a
response to our environment
– Seeing when to lift our hand to catch a fly
ball
2-107
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Structural Kinesiology
Neuromuscular Fundamentals
2-108
18
Proprioception & Kinesthesis
Proprioception & Kinesthesis
• Taken for granted are sensations
associated with neuromuscular activity
through proprioception
• Proprioceptors - internal receptors
located in skin, joints, muscles, &
tendons which provide feedback relative
to tension, length, & contraction state of
muscle, position of body & limbs, and
movements of joints
• Proprioceptors work in combination with
other sense organs to accomplish
kinesthesis
• Kinesthesis – conscious awareness of
position & movement of the body in
space
• Proprioceptors specific to muscles
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
– Muscles spindles
– Golgi tendon organs (GTO)
2-109
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Structural Kinesiology
Proprioception & Kinesthesis
• Proprioception
– Meissner’s corpuscles
– Ruffini’s corpuscles
– Pacinian corpuscles
– Krause’s end-bulbs
Neuromuscular Fundamentals
2-110
Proprioception & Kinesthesis
• Proprioceptors specific to joints & skin
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
– Subconscious mechanism by which body is
able to regulate posture & movement by
responding to stimuli originating in
proprioceptors of the joints, tendons,
muscles, & inner ear
2-111
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Structural Kinesiology
Proprioception & Kinesthesis
Neuromuscular Fundamentals
2-112
Proprioception & Kinesthesis
• Muscle spindles
•
– concentrated primarily in muscle belly
between the fibers
– sensitive to stretch & rate of stretch
– Insert into connective tissue within muscle &
run parallel with muscle fibers
– Spindle number varies depending upon level
of control needed
Muscle spindles & myotatic
or stretch reflex
1. Rapid muscle stretch occurs
2. Impulse is sent to the CNS
3. CNS activates motor neurons
of muscle and causes it to
contract
• Ex. Greater concentration in hands than thigh
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Neuromuscular Fundamentals
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Neuromuscular Fundamentals
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19
Proprioception & Kinesthesis
Proprioception & Kinesthesis
• Ex. Knee jerk or patella tendon reflex
• Ex. Knee jerk or patella tendon reflex
– Reflex hammer strikes patella tendon
– Causes a quick stretch to musculotendinis
unit of quadriceps
– In response quadriceps fires & the knee
extends
• More sudden the tap, the more significant
the reflexive contraction
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Neuromuscular Fundamentals
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Proprioception & Kinesthesis
•
2-117
Proprioception & Kinesthesis
2-118
– concentrated around joint capsules,
ligaments, tendon sheaths & beneath skin
– activated by rapid changes in joint angle & by
pressure changes affecting the capsule
– activation only last briefly & is not effective in
detecting constant pressure
– helpful in providing feedback regarding the
location of a body part in space following
quick movements such as running or jumping
• GTO protects us from an excessive
contraction by causing its muscle to
relax
Neuromuscular Fundamentals
Neuromuscular Fundamentals
• Pacinian corpuscles
GTO stretch threshold is reached
Impulse is sent to CNS
CNS causes muscle to relax
facilitates activation of antagonists as a
protective mechanism
Manual of
Structural Kinesiology
Manual of
Structural Kinesiology
Proprioception & Kinesthesis
• Tension in tendons & GTO increases as
muscle contract, which activates GTO
1.
2.
3.
4.
Golgi tendon organ
– found serially in the tendon
close to muscle tendon
junction
– sensitive to both muscle
tension & active contraction
– much less sensitive to stretch
than muscle spindles
– require a greater stretch to be
activated
– Ex. Quick short squat before attempting a
jump
– Quick stretch placed on muscles in the squat
enables the same muscles to generate more
force in subsequently jumping off the floor
Neuromuscular Fundamentals
2-116
Proprioception & Kinesthesis
• Stretch reflex may be utilized to facilitate
a greater response
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Neuromuscular Fundamentals
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Neuromuscular Fundamentals
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20
Proprioception & Kinesthesis
Proprioception & Kinesthesis
• Ruffini’s corpuscles
• Ruffini’s corpuscles
– located in deep layers of the skin and the
joint capsule
– activated by strong & sudden joint
movements as well as pressure changes
– reaction to pressure changes are slower to
develop
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
– activation is continued as long as pressure
is maintained
– essential in detecting even minute joint
position changes & providing information
as to exact joint angle
2-121
Proprioception & Kinesthesis
2-123
Manual of
Structural Kinesiology
All or None Principle
2-124
• Typical muscle contraction
– The number of motor units responding (and
number of muscle fibers contracting) within
the muscle may vary significantly from
relatively few to virtually all
– depending on the number of muscle fibers
within each activated motor unit & the
number of motor units activated
– Single motor neuron & all
muscle fibers it
innervates
– Function as a single unit
Neuromuscular Fundamentals
Neuromuscular Fundamentals
All or None Principle
• When muscle contracts,
contraction occurs at the
muscle fiber level within
a particular motor unit
• Motor unit
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Structural Kinesiology
2-122
• Quality of movement & reaction to
position change is dependent upon
proprioceptive feedback from muscles &
joints
• Proprioception may be enhanced
through specific training
– located in the skin & other subcutaneous
tissues
– important in receiving stimuli from touch
– not as relevant to kinesthesis
Neuromuscular Fundamentals
Neuromuscular Fundamentals
Proprioception & Kinesthesis
• Meissner’s corpuscles & Krause’s endbulbs
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Structural Kinesiology
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Structural Kinesiology
2-125
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Structural Kinesiology
Neuromuscular Fundamentals
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21
Factors affecting muscle tension
development
All or None Principle
• Difference between lifting a minimal vs.
maximal resistance is the number of muscle
fibers recruited
• The number of muscle fibers recruited may
be increased by
• All or None Principle - regardless of
number, individual muscle fibers within
a given motor unit will either fire &
contract maximally or not at all
– activating those motor units containing a greater
number of muscle fibers
– activating more motor units
– increasing the frequency of motor unit activation
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Structural Kinesiology
Neuromuscular Fundamentals
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Structural Kinesiology
Neuromuscular Fundamentals
Factors affecting muscle tension
development
Factors affecting muscle tension
development
• Number of muscle fibers per motor unit
varies significantly
• Motor unit must first receive a stimulus
via electrical signal known as an action
potential for the muscle fibers in the unit
to contract
• Subthreshold stimulus
– From less than 10 in muscles requiring
precise and detailed such as muscles of
the eye
– To as many as a few thousand in large
muscles that perform less complex
activities such as the quadriceps
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
– not strong enough to cause an action
potential
– does not result in a contraction
2-129
Factors affecting muscle tension
development
Neuromuscular Fundamentals
2-130
• Submaximal stimuli
– stimulus becomes strong enough to
produce an action potential in a single
motor unit axon
– all of the muscle fibers in the motor unit
contract
Neuromuscular Fundamentals
Manual of
Structural Kinesiology
Factors affecting muscle tension
development
• Threshold stimulus
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Structural Kinesiology
2-128
– Stimuli that are strong enough to produce
action potentials in additional motor units
• Maximal stimuli
– Stimuli that are strong enough to produce
action potentials in all motor units of a
particular muscle
2-131
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Structural Kinesiology
Neuromuscular Fundamentals
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22
Factors affecting muscle tension
development
Factors affecting muscle tension
development
• As stimulus strength increases from threshold up to
maximal more motor units are recruited & overall
muscle contraction force increases in a graded fashion
• Greater contraction forces may also be
achieved by increasing the frequency or
motor unit activation
• Phases of a single muscle fiber
contraction or twitch
–
–
–
–
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Structural Kinesiology
Neuromuscular Fundamentals
2-133
Factors affecting muscle tension
development
2-134
– When successive stimuli are provided before
relaxation phase of first twitch has completed,
subsequent twitches combine with the first to
produce a sustained contraction
– Generates a greater amount of tension than
single contraction would produce individually
– As frequency of stimuli increase, the resultant
summation increases accordingly producing
increasingly greater total muscle tension
• Contraction phase
– Muscle fiber begins shortening
– Lasts about 40 milliseconds
• Relaxation phase
– Follows contraction phase
– Last about 50 milliseconds
2-135
Factors affecting muscle tension
development
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Structural Kinesiology
Neuromuscular Fundamentals
2-136
Factors affecting muscle tension
development
• Tetanus
• Treppe
– Occurs when multiple
maximal stimuli are provided
at a low enough frequency to
allow complete relaxation
between contractions to
rested muscle
– Slightly greater tension is
produced by the 2nd stimulus
than with 1st
– results if the stimuli are provided at a
frequency high enough that no relaxation
can occur between contractions
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
• Summation
– Brief period of a few
milliseconds following stimulus
Neuromuscular Fundamentals
Manual of
Structural Kinesiology
Factors affecting muscle tension
development
• Latent period
Manual of
Structural Kinesiology
Stimulus
Latent period
Contraction phase
Relaxation phase
Neuromuscular Fundamentals
2-137
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Structural Kinesiology
Neuromuscular Fundamentals
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23
Factors affecting muscle tension
development
Muscle Length - Tension Relationship
• Treppe
• Maximal ability of a
muscle to develop
tension & exert force
varies depending
upon the length of the
muscle during
contraction
– 3rd stimulus produces even
greater tension than the 2nd
– Staircase effect occurs only
with the 1st few stimuli
– Resultant contractions after
the initial ones result in equal
tension being produced
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Structural Kinesiology
Neuromuscular Fundamentals
2-139
Muscle Length - Tension Relationship
• Generally, depending upon muscle
involved
Neuromuscular Fundamentals
2-141
• Ex. 1 Increasing ability to
exert force
Muscle Length - Tension Relationship
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Structural Kinesiology
Neuromuscular Fundamentals
2-142
Muscle Force – Velocity Relationship
• When muscle is contracting (concentrically or
eccentrically) the rate of length change is
significantly related to the amount of force
potential
• When contracting concentrically against a
light resistance muscle is able to contract at a
high velocity
– squat slightly to stretch the
calf, hamstrings, & quadriceps
before contracting same
muscles concentrically to jump
• Ex. 2. Reducing ability to
exert force
– isolate the gluteus maximus by
maximally shortening the
hamstrings with knee flexion
Neuromuscular Fundamentals
2-140
– A proportional decrease in ability to
develop tension occurs as a muscle is
shortened
– When shortened to around 50% to 60% of
resting length ability to develop contractile
tension is essentially reduced to zero
Muscle Length - Tension Relationship
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
• Generally, depending upon muscle
involved
– Greatest amount of tension can be
developed when a muscle is stretched
between 100% to 130% of its resting length
– Stretch beyond 100% to 130% of resting
length significantly decreases the amount
of force muscle can exert
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Structural Kinesiology
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Structural Kinesiology
2-143
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Structural Kinesiology
Neuromuscular Fundamentals
2-144
24
Muscle Force – Velocity Relationship
Muscle Force – Velocity Relationship
• As resistance increases, the maximal velocity
at which muscle is able to contract decreases
• Eventually, as load increases, the velocity
decreases to zero resulting in an isometric
contraction
• As load increases beyond muscle’s ability to
maintain an isometric contraction, the muscle
begins to lengthen resulting in an eccentric
contraction
• Slight increases in load results in relatively
low velocity of lengthening
• As load increases further the velocity of
lengthening will increase as well
• Eventually, load may increase to point where
muscle can no longer resist, resulting in
uncontrollable lengthening or dropping of load
• Inverse relationship between concentric
velocity & force production
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Neuromuscular Fundamentals
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Structural Kinesiology
Neuromuscular Fundamentals
Muscle Force – Velocity Relationship
Angle of pull
• As force needed to cause movement of an
object increases the velocity of concentric
contraction decreases
• Somewhat proportional relationship between
eccentric velocity & force production
• As force needed to control an object’s
movement increases, the velocity of eccentric
lengthening increases, at least until when
control is lost
• Angle between the line of pull of the muscle &
the bone on which it inserts (angle toward the
joint)
• With every degree of joint motion, the angle
of pull changes
• Joint movements & insertion angles involve
mostly small angles of pull
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Angle of pull
Neuromuscular Fundamentals
2-148
Angle of pull
• Rotary component (vertical component) component of muscular force that acts
perpendicular to long axis of bone (lever)
• Angle of pull decreases as bone moves away
from its anatomical position through local
muscle group’s contraction
• Range of movement depends on type of joint
& bony structure
• Most muscles work at angles of pull less than
50 degrees
• Amount of muscular force needed to cause
joint movement is affected by angle of pull
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
2-146
– When the line of muscular force is at 90
degrees to bone on which it attaches, all of
the muscular force is rotary force (100% of
force is contributing to movement)
– All of force is being used to rotate the lever
about its axis
– The closer the angle of pull to 90 degrees,
the greater the rotary component
2-149
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Neuromuscular Fundamentals
2-150
25
Angle of pull
Angle of pull
• If angle is less than 90
degrees, the force is a
stabilizing force because its
pull directs the bone toward the
joint axis
• If angle is greater than 90
degrees, the force is
dislocating due to its pull
directing the bone away from
the joint axis
• At all other degrees of the angle of pull, one
of the other two components of force are
operating in addition to rotary component
– Rotary component continues with less force, to
rotate the lever about its axis
– Second force component is the horizontal, or
nonrotary component and is either a stabilizing
component or a dislocating component, depending
on whether the angle of pull is less than or greater
than 90 degrees
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Neuromuscular Fundamentals
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– Cross & act directly only on the joint that
they cross
– Ex. Brachialis
• Can only pull humerus & ulna closer
together
– chin-up (pull-up)
– angle makes the chin-up easier because of
more advantageous angle of pull
– compensate for lack of sufficient strength
2-153
Uniarticular, biarticular, and multiarticular
muscles
• Biarticular muscles – cross & act on two
different joints
Neuromuscular Fundamentals
2-154
Uniarticular, biarticular, and multiarticular
muscles
– The concentric shortening of the muscle to
move one joint is offset by motion of the
other joint which moves its attachment of
muscle farther away
– This maintenance of a relatively constant
length results in the muscle being able to
continue its exertion of force
• can cause and/or control motion at more than
one joint
• are able to maintain a relatively constant length
due to "shortening" at one joint and
"lengthening" at another joint
Neuromuscular Fundamentals
Manual of
Structural Kinesiology
• Muscle does not actually shorten at one
joint & lengthen at other
– Depending, biarticular muscles may
contract & cause motion at either one or
both of its joints
– Two advantages over uniarticular muscles
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Structural Kinesiology
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• Uniarticular muscles
• Sometimes desirable to begin with the
angle of pull is at 90 degrees
Neuromuscular Fundamentals
Neuromuscular Fundamentals
Uniarticular, biarticular, and multiarticular
muscles
Angle of pull
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Structural Kinesiology
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26
Uniarticular, biarticular, and multiarticular
muscles
• Ex.1 Hip & knee biarticular muscles
• Ex. 2 Hip & knee biarticular muscles
– Concurrent movement pattern occurs when
both the knee & hip extend at the same
time
– If only knee extension occurs, rectus
femoris shortens & loses tension as do
other quadriceps muscles, but its relative
length & subsequent tension may be
maintained due to its relative lengthening
at the hip joint during extension
Manual of
Structural Kinesiology
Neuromuscular Fundamentals
– Countercurrent movement pattern occurs
in kicking
– During the lower extremity forward
movement phase the rectus femoris
concentrically contracts to flex the hip &
extend the knee
– These two movements, when combined,
increase the tension or stretch on the
hamstring muscles both at the knee & hip
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Uniarticular, biarticular, and multiarticular
muscles
• Multiarticular muscles act on three or
more joints due to the line of pull
between their origin & insertion crossing
multiple joints
• Principles relative to biarticular muscles
apply similarly to multiarticular muscles
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Reciprocal Inhibition or Innervation
– This reciprocal innervation effect occurs through
reciprocal inhibition of the antagonists
– Activation of the motor units of the agonists
causes a reciprocal neural inhibition of the motor
units of the antagonists
– This reduction in neural activity of the antagonists
allows them to subsequently lengthen under less
tension
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Neuromuscular Fundamentals
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Active & Passive Insufficiency
• As muscle shortens its ability to exert
force diminishes
• Ex. Compare the ease of
– stretching hamstrings when simultaneously
contracting the quadriceps
vs.
– stretching hamstrings without contracting
quadriceps
Neuromuscular Fundamentals
Manual of
Structural Kinesiology
• Antagonist muscles groups must relax &
lengthen when the agonist muscle group
contracts
Reciprocal Inhibition or Innervation
Manual of
Structural Kinesiology
Uniarticular, biarticular, and multiarticular
muscles
– Active insufficiency is reached when the
muscle becomes shortened to the point
that it can not generate or maintain active
tension
– Passively insufficiency is reached when
the opposing muscle becomes stretched
to the point where it can no longer
lengthen & allow movement
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Neuromuscular Fundamentals
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Active & Passive Insufficiency
Active & Passive Insufficiency
• Easily observed in either biarticular
or multiarticular muscles when full
range of motion is attempted in all
joints crossed by the muscle
– Similarly, hamstrings can not usually
stretch enough to allow both maximal hip
flexion & maximal knee extension due
passive insufficiency
– Ex. Rectus femoris contracts
concentrically to both flex the hip &
extend the knee
– Can completely perform either action
one at a time but actively insufficient to
obtain full range at both joints
simultaneously
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Structural Kinesiology
Neuromuscular Fundamentals
• As a result, it is virtually impossible to
actively extend the knee fully when
beginning with the hip fully flexed or
vice versa
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Web Sites
Neuromuscular Fundamentals
U.S. National Library of Medicine’s Visible Human Project
AnatQuest Anatomic Images Online
http://anatline.nlm.nih.gov/AnatQuest/AwtCsViewer/aq-cutaway.html
– A great resource using a cut-away viewer to see cadaver images
throughout the body to identify the relevant anatomy.
The Physician and Sportsmedicine
www.physsportsmed.com/issues/1997/10oct/laskow.htm
– Refining rehabilitation with proprioception training: expediting
return to play.
Get Body Smart
www.getbodysmart.com/index.htm
– An online interactive tutorial on the muscular and nervous
systems.
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Web Sites
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Neuromuscular Fundamentals
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Web Sites
Neurologic Exam: An anatomical approach
http://medlib.med.utah.edu/neurologicexam/home_exam.html
– A very thorough site on neurological exams, including numerous
movies with both normal and pathological results.
Cranial Nerves: Review info
www.gwc.maricopa.edu/class/bio201/cn/cranial.htm
– A good resource on the cranial nerves.
University of Arkansas for Medical Sciences Nerve tables
http://anatomy.uams.edu/anatomyhtml/nerves.html
– Numerous tables of all nerves throughout the body.
Dermatomes
www.meddean.luc.edu/lumen/MedEd/GrossAnatomy/learnem/derma
t/main_der.htm
– An interactive review of the body’s dermatomes.
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Web Sites
Human Anatomy Online
http://innerbody.com/image/musfov.html
– An interactive site with details on the muscular and nervous
systems.
BBC Science & Nature
http://bbc.co.uk/science/humanbody/body/interactives/3djigsaw_02/
index.shtml
– An interactive site allowing you to select the innervation for the
muscles.
Functions of the Muscular System
http://training.seer.cancer.gov/module_anatomy/unit41_muscle_fun
ctions.html
– Several pages with information on skeletal muscle structure,
types, and groups, along with unit review and quizzes.
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Neuromuscular Fundamentals
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Loyola University Medical Education Network Master Muscle List
www.meddean.luc.edu/lumen/MedEd/GrossAnatomy/dissector/mml
– An interactive and graphical review of the muscles indexed
alphabetically and by region.
Proprioception Exercises Can Improve Balance
http://sportsmedicine.about.com/library/weekly/aa062200.htm
– Proprioception.
Meds 1 Neurophysiology 2003
www.med.uwo.ca/physiology/courses/medsweb
– A site on neurophysiology with Flash animation.
Muscular System
www.bio.psu.edu/faculty/strauss/anatomy/musc/muscular.htm
– Cadavaric photos of the cat muscular system.
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Neuromuscular Fundamentals
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Web Sites
Functions of the Nervous System
http://training.seer.cancer.gov/module_anatomy/unit51_nerve_functi
ons.html
– Several pages with information on the nervous system
organization, nerve structure, unit review, and quizzes.
Training for Proprioception & Function
www.coachr.org/proprio.htm
– Information on improving body awareness movement efficiency.
Fitter International
www.fitter1.com/article_proprioception.html?mtcPromotion=Articles
%3EProprioception
– Products and articles on proprioception.
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Neuromuscular Fundamentals
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