7- how muscle morphology influences function

Question 1

isometric contraction

Answer 1

no muscle length change

force made by the muscle is equal to the load

Question 2

concentric contraction

Answer 2

force > load

muscle shortens

Question 3

eccentric contraction

Answer 3

force < load
controlled lengthening
the load lengthens the muscle, contraction slows it down

Question 4

open chain movement

Answer 4

action performed on a freely moving body part

Question 5

closed chain movement

Answer 5

action is changed/altered due to the fixation of a body part

Question 6

sarcomere

Answer 6

functional unit within a muscle fibre

can be shortened by up to 40% of resting length

Question 7

force is created by

Answer 7

connections of actin and myosin proteins

Question 8

distal insertion

Answer 8

mechanical advantage = more torque
innately string irrespective of muscle size
slow, limited segment movement

Question 9

proximal insertion

Answer 9

smaller torque
fast and large segment movement
same amount of mucle shortening creastes more degrees of joint change
innately weaker at moving loaded segments

Question 10

3 types of muscle architecture

Answer 10

parellel orientation
convergent
pennated

Question 11

cross sectional area of a muscle

Answer 11

increases force

Question 12

parallel orientation

Answer 12

fusiform, flat, strap

move quickly against little force

Question 13

convergent muscle

Answer 13

fan/traingle
dfferent aspects of the muscle can have different architectures
broad range of uses

Question 14

pennated muscles

Answer 14

resembling a feather

can be uni, bi, multi

Question 15

why is pennate less efficient

Answer 15

creates force at a differetn angle to the tendon

Question 16

advantage of a pennate muscle

Answer 16

with minimal change of muscle girth significant movement can be created
because sarcomeres are in parallel

Question 17

<10° pennated angle

Answer 17

more force than parallel but less movement

Question 18

35°

Answer 18

optimal power generation

increase in power offsets the decrease in efficiency

Question 19

> 35°

Answer 19

less movement but more static tension

postural stability