Tissue Mechanics: Muscle Flashcards Preview

Biomechanics > Tissue Mechanics: Muscle > Flashcards

Flashcards in Tissue Mechanics: Muscle Deck (23)
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1
Q

what type of muscles are used to generate positive work?

A

mono-articular muscles

2
Q

what type of muscles are used to transfer energy between joints?

A

bi-articular muscles

3
Q

describe the fiber length as you transition from parallel muscles to pennate muscles?

A
parallel muscles (long fibers)
pennate muscles (short fibers)
4
Q

describe the change in velocity and force for parallel muscles and pennate muscles.

A

parallel muscles- low force; high velocity

pennate muscles- high force; low velocity

5
Q

what happens to the pennation angle when the muscle gets shorter?

A

pennation angle decreases

6
Q

which muscle packs more fibers (and thus more force)?

A

pennate muscles

7
Q

what does a low fiber length/muscle length ratio indicate?

A

high force muscle

low ratio: FL/ML = 0.2

8
Q

what does a high fiber length/muscle length ratio indicate?

A

high velocity muscle

high ratio: FL/ML = 0.6

9
Q

what contributes to the larger contraction force of a muscle?

A

the greater the number of cross-bridges attached to actin filaments

10
Q

a single stimulus from a motor neuron results in what response from a muscle fiber?

A

a twtich

11
Q

if the frequency of stimuli is rapid enough, what results in a response from a muscle fiber?

A

a tetanic response

12
Q

what is a concentric, isometric, and eccentric contraction?

A

concentric- shortening contraction
isometric- joint angle remains cosntant
eccentric- lengthening contraction

13
Q

which contraction develops the greatest force when maximally stimulated?

A

eccentric contraction - greatest force developed

concentric contraction - least force developed

14
Q

what is isotonic contraction?

A

uniform tension in the muscle

15
Q

what is isokinetic contraction?

A

length is changing, but at the same rate

16
Q

what is co-contraction?

A

simultaneous contraction of agonist and antagonist

17
Q

which type of muscle has a high proportion of slow-twich (type 1 fibers)? what about fast twitch (type 2a & 2b fibers)?

A

tonic or stability muscles- slow twitch (type 1) fibers

phasic or mobility muscles- fast twitch (type 2a&2b fibers)

18
Q

what are tonic or stability muscles used for?

A

used primarily to maintain posture

e.g. soleus

19
Q

what are phasic or mobility muscles used for?

A

for short powerful actions

e.g. biceps

20
Q

what is the working range for mechanical behavior of muscle?

A

70-120% of its length

21
Q

for a concentric contraction, what type (slow/fast) contractions produce more force?

A

slower contractions

22
Q

for an eccentric contraction, what type (slow/fast) contractions produce more force?

A

faster contractions

23
Q

what factors affect max. joint torque?

A
  1. muscle cross-sectional area
  2. position of joint
  3. direction of contraction
  4. speed of contraction