11: Soft Tissue Mechanics V - Vardaxis Flashcards

1
Q

muscles make ..

A

moments

- force acts at a distance from the joint center, this produces a moment of force about the joint center

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2
Q

muscles primarily used to generate positive work

A

mono-articular muscles

bi-articualr muscles are used for energy transfer between joints

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3
Q

quadriceps produce _________ via hamstrings

A

hip extension

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4
Q

quadriceps produce ____________ via gastrocnemius

A

plantarflexoin

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5
Q

high force muscle architecture

A

pennate, short fibers

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6
Q

high velocity muscle architecture

A

long fibers, parallel

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7
Q

more fibers in area =

A

more force

pennate shape can get more fibers in same area than parallel

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8
Q

FL/ML ration

A

fiber length/ muscle length ration

low = force (0.2)

high = velocity (0.6)

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9
Q

action responsible for the contraction of a muscle occurs within a ____________

A

sarcomere

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10
Q

____________ number of cross bridges attached to the actin filaments, the larger the contraction force

A

greater

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11
Q

muscle’s smallest force generating unit

A

sarcomere

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12
Q

force is generated by

A

cross bridges

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13
Q

twitch

A

a single stimulus from the motor neuron results ina twitch response of the fiber

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14
Q

if the frequency of the stimuli is rapid enough ….

A

a tetanic response of the fibers results

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15
Q

concentric

A

shortening contraction

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16
Q

least force developed when maximally stimulated = ____ greatest =

A

concentric

eccentric

17
Q

joint angle remamins constant

A

isometric

18
Q

lengthening contraction

A

eccentric

19
Q

uniform tension in muscle

A

isotonic

20
Q

constant angular velocity

A

isokinetic

21
Q

simultaneous contraction of agonist and antagonist

A

co-contraction

22
Q

ways in which a synergist may act:

A

(a muscle which helps the agonist in some way)

  • similar action to agonist
  • stabilizes neighboring joint
  • prevents unwanted actions by agonist
23
Q

when passive (not contracting) muscle acts like a …

A

spring (force-length graph)

24
Q

peak in active curve on force-length graph occurs at

A

Io - resting state of muscle

25
Q

physiological working range of muscle (% of resting length)

A

70-120%

26
Q

for a concentric contraction, slower contraction produce _______ force

A

MORE

for an eccentric contraction faster contractions produce more force

27
Q

factors affecting maximal joint torque

A
  • muscle cross-sectional area
  • position of joint
  • direction of contraction
  • speed of contraction