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PT 711-Kinesiology > Exam 2 > Flashcards

Exam 2 Flashcards

1
Q

motor units

A
  • single motor neuron, junctions, and fibers it controls

- can contain several axons

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2
Q

how many fibers can each axon innervate?

A

5-2000 fibers

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3
Q

parallel muscle fibers have___

A

greater range of motion

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4
Q

most common type of muscle

A

bipennate

-fibers on both sides of tendon

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5
Q

characteristics of oblique muscle fiber orientation:

A
  • shorter
  • more numerous
  • greater strength
  • shorter ROM
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6
Q

isotonic:

A
  • constant load

- fibers change length

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7
Q

isokinetic:

A
  • fixed speed

- variable accommodating resistance

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8
Q

isokinetic accommodates to:

A

ROM
pain
fatigue

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9
Q

factors influencing motion

A
  1. PROM
  2. Fiber length
  3. Relationship of length and moment arm
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10
Q

effect of moment arm length and ROM

A

the shorter the moment arm the great the distal part moves through an arc

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11
Q

effect of moment arm on strength of muscle

A

longer moment arm as greater torque which equals more strength

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12
Q

greatest tension in the muscle can develop when:

A

there is the most cross bridges which is at resting length

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13
Q

faster contraction (concentric) =

A

lower force

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14
Q

faster contraction (eccentric)=

A

higher force

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15
Q

Henneman Size Principle

A

smaller motor units are recruited first

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16
Q

decreased activity produces most atrophy in:

A

antigravity muscles

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17
Q

shortened muscle position from inactivity increases rate of____

A

protein loss

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18
Q

lost muscle mass in replaced by:

A
  • adipose tissue
  • fibrous connective tissue
  • called senile sarcopenia
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19
Q

cross-sections of which type of muscle decrease faster from aging?

A

type II

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20
Q

tendon and ligament structure

A
  • dense regular connective tissue
  • mostly type I collagen and water
  • some type III collagen
  • very little elastin in tendons
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21
Q

proteoglycans in tendon/ligament

A

tendon has less proteoglycans than ligament

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22
Q

elastic region of tendon/ligament

A

-crip straightening by collagen sliding past each other

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23
Q

substance tear

A

middle of the tendon/ligament

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24
Q

avulsion

A

tendon/liagment pulls piece of bone out

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25
Q

ligament failure more affected by:

A

age than rate of action

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26
Q

increased rate of force in ligament/tendon

A

-increased brittle behavior (failure liekely to occur by rupture)

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27
Q

lower rate of force on ligament/tendon

A

less brittle nature so avulsion more likely

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28
Q

start to get tissue changes at temperature

A

37-40 degrees celcius

-above 60 celcius results in collagen shrinkage

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29
Q

effect of maturation/aging on tendon/ligament

A
  • decrease collagen and GAG
  • increased elastin
  • decreased crimp angle (reduced stiffness)
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30
Q

changes in tendon from aging can be minimized by:

A

low to moderate intensity resistance exercise

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31
Q

hormones that reduce strength of connective tissue

A
  • adrenocorticotropic hormone
  • cortisone
  • relaxin
  • lower GAG content
  • Reduce collagen synthesis type I
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32
Q

better to be in ___ position when immobilized

A

lengthened

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33
Q

best for tendon stimulation:

A

low to moderate tension

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34
Q

thickest articular cartilage in the body:

A

lunate surface

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35
Q

purpouse of neck of femur

A
  • greater lever arm and angle for the least amount of energy expended
  • gets the shaft farther from the body to avoid impingement
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36
Q

bowing of femur

A
  • compresses posterior

- tension anterior

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37
Q

what reduces the angle of inclination after birth?

A

walking

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38
Q

angle of inclination at birth

A

140-150 degrees

normal is 125 degrees

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39
Q

coxa valga

A

angle of inclination of 140 degrees

  • associated with genu varum
  • often leads to dislocation
  • decreases bending moment arm
  • less shear force aross femoral head
  • increased function length of hip abductors
  • decreased moment arm for abductor force
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40
Q

coxa vara

A

angle of inclination of 105 degrees

  • associated with genu valgum
  • increase moment arm for abductors
  • may increase stability
  • increased bending moment arm which increases shearing across femoral neck
  • shortens functional length of abductors
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41
Q

which is more stable, coxa valga or vara?

A

coxa vara is more stable than valga

42
Q

excessive femoral anteversion

A
  • greater than 20 degrees

- usually causes toeing in for better advantage of hip abductors

43
Q

acetabular anteversion

A
  • 20 degrees
  • less stable
  • dislocate anterior
44
Q

posterior hip capsule resists

A

hip flexion

hip IR

45
Q

what resists hip IR

A
  • external rotators
  • ischiofemoral ligament
  • posterior capsule
46
Q

what would decreased center edge angle do?

A

superior dislocation

47
Q

taut tissue in hip flexion (knee ext)

A

hamstrings

48
Q

taut tissues in hip flexion knee flex.

A

inferior and posterior capsule

-gluteus maximus

49
Q

taut tissues in hip extension (knee ext.)

A 
iliofemoral ligament
-some pubofemoral 
-some ischiofemorl
al
-some psoas major
50
Q

taut tissues in hip extension (knee flex.)

A

rectus femoris

51
Q

taut tissues in hip abduction

A
  • pubofemoral ligament

- adductor muscles

52
Q

taut tissues in hip adduction

A
  • superior fibers of ischiofemoral ligament
  • iliotibial band
  • tensor fasciae latae
  • gluteus medius
53
Q

taut tissue in hip IR

A
  • ischiofemoral ligament

- external rotator muscles : piriformis gluteus maximus

54
Q

taut tissue in hip ER

A
  • iliofemoral and pubofemoral ligaments

- internal rotator muscles: tensor fasciae latae, gluteus minimus

55
Q

closed packed position for the hip

A
  • full ext
  • slight IR
  • slight abd
56
Q

loose-packed position for the hip

A

30 degrees flexion and abduction, slight ER

57
Q

hip capsular pattern

A

medial rotation limited more than flexion and abduction

-no limitation in lateral rotation or adduction

58
Q

rotation of hip during gait

A
  • forward leg has hip ER

- following leg has hip IR

59
Q

normal hip flexion

60
Q

normal hip extension

61
Q

normal hip abduction

62
Q

normal hip adduction

63
Q

normal hip internal rotation

64
Q

normal hip external rotation

65
Q

normal hip inclination

66
Q

normal hip anteversion

67
Q

normal knee flexion

68
Q

normal knee extension

69
Q

normal knee IR/ER

A

45 together

-more ER than IR

70
Q

normal knee Q-angle

71
Q

wolf’s law

A

increased bone loading = increased bone strengthening

72
Q

factors that influence muscle strength

A
  • pCSA (size)
  • stretch
  • moment arm
  • contraction velocity
  • motor unit recruitment
73
Q

effect of aging on muscle

A
  • loss of skeletal muscle mass from inactivity
  • replaced as adipose tissue
  • reduction in myofibers
  • slower circulatory supply
  • decreased capacity to recover from exercise
  • decrease of elasticity
74
Q

strap muscles

A

rectus abdominis

sternocleidomastoid

75
Q

fusiform muscles

A

biceps brachii

brachialis

76
Q

rhomboidal muscles

A
  • rhomboids

- pronator quadratus

77
Q

triangular muscles

A

pectoralis major

78
Q

unipennate muscle

A

-all of the muscle fibers are on the same side of the tendon

79
Q

bipennate muscle

A

the most common type, has muscle fibers on both sides of the tendon

80
Q

multipennate muscle

A

has branches of the tendon within the muscle

81
Q

oblique muscle fibers

A
  • shorter but more numerous
  • greater strength potential
  • shorter ROM
82
Q

prolonged muscle shortening

A
  • loss of sarcomeres

- may depend on immobilization and specific muscles

83
Q

a faster concentric contraction has a

A

lower force

84
Q

a faster eccentric contraction has a

A

higher force

85
Q

effect of age on ligament/tendon

A
  • decrease collagen and GAG
  • increased elastin
  • decreased crimp angle
  • reduced stiffness
86
Q

effect of inactivity on muscle

A
  • atrophy
  • decreased strength (especially in shortened position)
  • transition type I to type II
87
Q

lose packed position of knee

A

25 degrees flexed

88
Q

close-packed position of knee

A

full extension and ER

89
Q

MCL (posterior-medial capsule

A
  1. resists valgus
  2. resists knee extension
  3. resists extemes of axial rotation (especially ER)
90
Q

LCL

A
  1. resists varus
  2. resists knee extension
  3. resists extremes of axial rotation
91
Q

posterior capsule

A
  1. resists knee extension
  2. oblique popliteal ligament resists knee ER
  3. posterio-lateral capsule resists varus
92
Q

ACL

A
  1. most fibers resist extension (anterior translation of tibia)
  2. resists extremes of varus, valgus, and axial rotation
93
Q

PCL

A
  1. most fibers resist knee flexion (post. translation of tibia)
  2. resists extremes of varus, valgus, and axial rotation
94
Q

what extensor has greatest pCSA

A

Gluteus maximus

adductor magnus

95
Q

abductor with the longest moment arm

A

gluteus medius

96
Q

hip abductor is the strongest with

A

extension; stabilizing during gait while you swing other leg through

97
Q

external rotator that has a small moment arm

A

obturator externus

98
Q

Factors guiding screw-home mechanism

A
  1. shape of medial femoral condyle
  2. tension in ACL
  3. Lateral pull of quadriceps
99
Q

menisci move __ with extension

100
Q

menisci move ___ with flexion

PT 711-Kinesiology (4 decks)

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