Tissue Mechanics V

Question 1

muscles make ..

Answer 1

moments

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

Question 2

muscles primarily used to generate positive work

Answer 2

mono-articular muscles

bi-articular muscles are used for energy transfer between joints

Question 3

quadriceps produce _________ via hamstrings

Answer 3

hip extension

Question 4

quadriceps produce ____________ via gastrocnemius

Answer 4

plantarflexion

Question 5

high force muscle architecture

Answer 5

pennate, short fibers

Question 6

high velocity muscle architecture

Answer 6

long fibers, parallel

Question 7

more fibers in area =

Answer 7

more force

pennate shape can get more fibers in same area than parallel

Question 8

FL/ML ration

Answer 8

fiber length/ muscle length ratio
low = force (0.2)
high = velocity (0.6)

Question 9

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

Answer 9

sarcomere

Question 10

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

Answer 10

greater

Question 11

muscle’s smallest force generating unit

Answer 11

sarcomere

Question 12

force is generated by

Answer 12

cross bridges

Question 13

twitch

Answer 13

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

Question 14

if the frequency of the stimuli is rapid enough ….

Answer 14

a tetanic response of the fibers results

Question 15

concentric

Answer 15

shortening contraction

Question 16

least force developed when maximally stimulated = ____ greatest =

Answer 16

concentric

eccentric

Question 17

joint angle remamins constant

Answer 17

isometric

Question 18

lengthening contraction

Answer 18

eccentric

Question 19

uniform tension in muscle

Answer 19

isotonic

Question 20

constant angular velocity

Answer 20

isokinetic

Question 21

simultaneous contraction of agonist and antagonist

Answer 21

co-contraction

Question 22

ways in which a synergist may act:

Answer 22

(a muscle which helps the agonist in some way)

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

Question 23

when passive (not contracting) muscle acts like a …

Answer 23

spring (force-length graph)

Question 24

peak in active curve on force-length graph occurs at

Answer 24

Io - resting state of muscle

Question 25

physiological working range of muscle (% of resting length)

Answer 25

70-120%

Question 26

for a concentric contraction, slower contraction produce _______ force

Answer 26

MORE

for an eccentric contraction faster contractions produce more force

Question 27

factors affecting maximal joint torque

Answer 27

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