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ephe 355 > muscle systems and movement > Flashcards

muscle systems and movement Flashcards

1
Q

type I muscle fibers:
diameter size
appearance
fatigue speed
metabolism
ex:

A

slow twitch/ oxidative fibers
- small diameter
- dark (myoglobin and mitochrondria)
- slow fatigue
- fibers depend on aerobic metabolism
ex: high % in postural muscles - erector spinae, soleus

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2
Q

type II muscle fibers:
diameter size
appearance
fatigue speed
metabolism
ex:

A

fast twitch/ fast oxidative - IIa and IIb
- large diameter
- white
- quick fatigue
- associated w anaerobic metabolism
ex: high % in phasic muscles (rapid force and power) ex: hamstrings, gastrocs, UE flexors

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3
Q

agonist muscle:

A

principle moving muscle that produces contraction (concentric, eccentric, isometric)

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4
Q

antagonist muscle:

A

produces opposite motion of agonist, typically passively elongates/ shorten during activity

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5
Q

do muscles pull w equal or unequal force on their origin and insertion?

A

equal

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6
Q

where are muscles the weakest?**

A

the musculotendinous junction

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7
Q

what conditions (4) make predicting muscle function possible and why do these conditions RARELY occur:

A
  1. proximal attachment is stabilized
  2. distal attachment moves towards proximal
    - proximal attachments often move toward the fixed distal attachments (CKC)
    - contractions can be con/ecce/isometric
  3. distal segment moves against gravity
    - movement can be assisted by gravity
  4. muscle acts alone
    - seldom occurs
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8
Q

isometric contraction:
action

A

no apparent change in joint angle
- stabilizing

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9
Q

concentric contraction:
action
work?

A

muscle shortening
- accelerating
- muscle is doing = positive work

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10
Q

eccentric contraction:
action
work?

A

muscle lengthening
- decelerating
- outside force responsible for motion being controlled by the muscle = negative work

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11
Q

isotonic activation:

A

contraction resulting in joint moving through ROM
*torque exerted by weight chnages as joint angle changes

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12
Q

isokinetic activation:

A

contraction occurs when rate of movement is constant

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13
Q

3 functions of a synergist (most common muscular function):

A
  • identical activity as agonist
  • stabilize proximal joints to support distal
  • obstruct unwanted agonist action (ex: flexor carpi radialis and extensor carpi radialis longus)
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14
Q

viscosity:

A

resistance to external force that causes permanent deformation
ex: heat to stretch

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15
Q

extensibility:

A

ability to stretch

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16
Q

elasticity:

A

ability to elongate and return to normal length

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17
Q

viscoelasticity:

A

the more extensibility a tissue has, the less viscosity

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18
Q

stress strain:

A

amount of deformation a structure can tolerate before succumbing to stress

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19
Q

is getting in the plastic range always bad?

A

no - microscopic damage b/n collagen fibrils occurs, but if muscle is too tight we might want that change

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20
Q

toe region

A

up to 2% strain - intital slack uptake

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21
Q

necking range

A

just before 10% strain = macroscopic damage
further strain = failure

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22
Q

creep:

A

elongation of tissue from low level load over time
ex: long duration stretching

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23
Q

dynamic stretching:
used when?

A

actively moving thorugh full ROM
- pre-activity

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24
Q

4 stretching types for gaining tissue length:

A
  1. static stretching = muscle moved into lengthened position
  2. active assisted
  3. PNF = contract/ relax to retain communication n/n brain&body part
  4. ballistic = rapid bouncing to push elongation
25
Q

C/I’s to stretching:

A
  • disrupt healing/ result in injury
  • myositis ossifications
  • incomplete fracture healing
  • joint subluxation/ dislocation
  • bony block
  • acute inflammation
  • sharp pain
  • hypermobile joints
  • shortened tissues = beneficial
    ex: high divers
    ex: deficient ACL - keep hammies tight to increase joint stability by decreasing muscular flexibility
26
Q

stretching precautions:

A
  • post injury; tissue healing stage
  • post immobilization or radiation
  • age of osteoporosis
  • muscle relaxants
  • newly healed fractures
  • ensure cooldown post exercise
  • know typical ROM and respect it
27
Q

does static stretching impair performance?

A

yes, if for 60+ seconds before strength tasks

28
Q

factors that influence muscle strength(8):

A
  1. muscle size
  2. fiber architecture
  3. passive components of muscles
  4. length-tension relationship of the muscle
  5. moment arm of the muscle
  6. speed of muscular contraction
  7. active tension
  8. age and gender
29
Q

2 parameters of muscle size:

A
  1. length = fibers in series
  2. width
30
Q

what is length vs width of muscle associated with/ what does it provide?

A

length:
- associated w speed
- longer muscles = mobility
width:
- associated w greater ability to produce force
- shorter muscles = stability

31
Q

how does CSA impact muscle?

A

larger CSA = greater force-generating capacity

32
Q

2 types of fiber architecture:

A
  1. fusiform
  2. pennate
33
Q

fusiform fibers:

A

“strap” = fasicles are long and parallel
- great distance, less form
ex: sartorious

34
Q

pennate fibers:
types?

A

attach at oblique angles to a common tendon = more rows of fibers
- greater capability to produce force
1. unipennate
2. bipennate
3. multipennate

35
Q

what is the total strength of pennate muscles?

A

sum of CSA of each pennate
more layers = more force

36
Q

3 types of fascia:

A
  1. endomysium = fiber layer
  2. perimysium = groups of fasicles
  3. epimysium = entire muscle
37
Q

passive components influencing muscle strength:

A
  1. parallel elastic component
  2. series elastic component
38
Q

parallel elastic component:

A

fascia is parallel to muscle fibers
muscle elongates past slack = fascia is passively stretched as muscle keeps lengthening

39
Q

series elastic component

A

tendon-muscle-tendon
muscle transfers forces along tendon to bone - motion

40
Q

do parallel and series lengthen together?

A

yes - this results in muscular stiffness/ tension

41
Q

when are the max crossbridges available?

A

at resting length

42
Q

when is torque typically greatest?

A

at mid range (100% of muscle force rotates joint when insertion is perpendicular to bone segment)

43
Q

how does angle of insertion influence torque?

A

changes line of pull and devotes force to compression or distraction

44
Q

does rate of m contraction affect m force?

A

yes
consider force velocity curve

45
Q

what is active tension?
affected by?

A

force produced by as muscle
affected by:
- #MU
- type of MU recruited
- rate/ frequency of MU firing

46
Q

which type of muscle fiber is recruited first?

A

small before big (larger axon = less excitable)
slow before fast (type I before II)

47
Q

how do age and sex impact muscle strength?

A
  • peak strength 20-30yrs
  • # MU decline w age
  • males > females
  • lean/whole body mass ratios
48
Q

muscle excursion:

A

how far a muscle can shorten beyond its resting length

49
Q

functional excursion:

A

the distance a muscle can shorten after being lengthened as far as its moveable joint allows

50
Q

what muscles have the most excursion?

A

2 joint muscles
- generate power in many places at once

51
Q

passive insufficiency

A

muscles elongated over 2+ joints simultaneously
- one muscle completely shortened, antagonist completely lengthened
ex: hamstring, hip flexor

52
Q

tenodesis

A

passive tension of 2 joint muscles resulting in passive movements of these joints

53
Q

active insufficiency

A

multijoint muscles
- cant create enough tension to concurrently move all joints through full ROM
ex: grip strength in wrist flexion

54
Q

biceps at elbow - which position is optimal?

A

length of muscle optimal at 0 (full extension) BUT
internal moment arm optimal at 90

55
Q

what contributes to crossbridge mechanisms and elastic forces?

A

mechanical contributions = PE returned as KE following rapid stretch of a muscle tendon unit
neural contributions = w quick stretch, facilitation of stretch reflex

56
Q

do most muscles show greater force at longer or shortened legnths?

A

longer
ex: pronator teres

57
Q

what muscles rely more on internal moment arms?

A

quadriceps femoris

58
Q

delayed onset muscle soreness:

A

decrease in ROM due to pain/ discomfort and decrease in max muscle forces
- damage at sarcomere level throughout muscle = body adapting, not bad

59
Q

muscle strain:

A

varying degrees of micro-macro strain
- typically at muscle-tendon junction

ephe 355 (7 decks)

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