Ch 4 Fiber Types, Size principle and other important characteristics of muscle tissue

Question 1

What are the different muscle fiber types

Answer 1

Type 1- slow twitch (50%)
Type 2 - fast twitch
Type 2a (25%)
Type 2x (25%)

Question 2

Strength=
power=

Answer 2

Strength=force
power=force and velocity

Question 3

What are some genetic factors for muscle fibers

Answer 3

Determine which a-motor neurons innervate fibers

Fibers differentiate based on a-motor neuron

Question 4

What causes most of loss of type 2 motor units

Answer 4

Aging

Question 5

Size of type 1 motor unit

Answer 5

smaller neuron, less than 300 fibers

Question 6

Size of type 2 motor unit

Answer 6

Larger neuron, grater than 300 fibers.

Question 7

When do muscle fibers reach peak power

Answer 7

at about 20% of peak force

Question 8

Which muscle is type 1 in everyone

Answer 8

soleus

Question 9

Which fiber types require oxygen for ATP production

Answer 9

Type 1
(recruited for low-intensity aerobic exercise and daily activities)

Question 10

Which fiber types Fatigue quickly and produce ATP anaerobically

Answer 10

Type 2

Question 11

Fibers used for short, intense endurance.
Produce more force

Answer 11

Type 2a

Question 12

Fibers used for short, explosive sprints

Answer 12

Type 2x

Question 13

Recruitment order for fibers

Answer 13

Type 1
Type 2a
Type 3a

Question 14

Less force production=

Answer 14

fewer or smaller motor units

Question 15

More force production =

Answer 15

more or larger motor units

Question 16

Explain the size prinicple

Answer 16

Order of recruitment relates directly to size of a-motor neuron. Smaller motor units fire first

Question 17

What fibers predominate in endurance athletes

Answer 17

Type 1

Question 18

What fibers predominate in sprinters

Answer 18

type 2

Question 19

What is fatigue

Answer 19

no more motor units to fire

Question 20

Contraction where the muscle produces force but does not change in length and the joint angle does not change

Answer 20

Static (isometric)

Question 21

Contraction where muscle produces force and changes length, and the joint movement is produced

Answer 21

Dynamic (isotonic)

Question 22

What is a concentric movement

Answer 22

Muscle shortens while producing force.
Sarcomere shortens; filaments slide toward center

Question 23

What is an Eccentric Movement

Answer 23

Muscle lengthens while producing force.
Cross-bridges form, but sarcomere lengthens
(trying to hold up a weight but it falls down slowly)

Question 24

What is DOMS

Answer 24

delayed onset muscle soreness. Eccentric motion causes this a lot

Question 25

What is the length-tension relationship

Answer 25

Optimal sarcomere length equals optimal overlap.
If too short or too stretched, little or no force develops
(ex jumping wind up)

Question 26

Force-Velocity relationship for concentric movement

Answer 26

Increase force = decrease velocity
Decrease force = increase velocity

Question 27

Force-Velocity relationship for Eccentric movement

Answer 27

Increase force = increase (negative) velocity
Decrease force = decrease (negative velocity)

Question 28

What is the velocity at isometric/static movement

Answer 28

0 m/s