4.3.1 Muscle Physiology, Exercise, and Physical Conditioning

Question 1

What are the 3 important contractile properties of muscle?

Answer 1

Maximal force, speed of force, muscle fiber efficiency (force produced and amount of ATP used)

Determined by the fiber type

Question 2

What are the three classifications of muscle fibers based on enzyme activity?

Answer 2

Question 3

Answer 3

Question 4

What happens when an alpha-motor nerve is stimulated?

Answer 4

All of the muscle fibers innervated by the alpha-motor nerve are stimulated

Question 5

In an untrained person, if they start exercise, what will be the conversion sequence of muscle?

(From untrained to trained)

Answer 5

Question 6

What type of muscle contraction creates a greater amount of force?

Answer 6

Eccentric contraction

Question 7

Is it possible to change muscle fiber type?

Answer 7

Yes

Question 8

What is the length-tension relationship b/t muscle?

Answer 8

Question 9

What are the standard end points of the sarcomere?

Answer 9

Z line to Z line

Question 10

What types of stimuli processes are part of the latency period?

Answer 10

Question 11

How does greater # of sarcomeres in parallel change force production?

Answer 11

Greater maximal force

Question 12

What characteristics are favored by long-term, low-intensity exercise?

Answer 12

Slow characteristics, power is low but production is more economical

Oxidative capacity - increased mitochondrial density is correlated with fatigue resistance

Question 13

What are the three types of muscle fibers? Are they glycotic or oxidative? Fast or slow?

Answer 13

Question 14

What allows for the production of tension?

Answer 14

Cross bridges b/t actin and myosin

Question 15

What type of fibers are lost due to increased age?

Answer 15

Fast fibers

Question 16

How can fiber types be differentiated histochemically?

Answer 16

Type of myosin

Question 17

What three factors determine the production of force in an isolated muscle?

Answer 17

Question 18

The sliding of the actin strand over the myosin strand during the contraction of muscle is called what?

Answer 18

The power stroke

Question 19

What are the six steps/phases of the myosin engagement with actin during the power stroke?

Answer 19

Question 20

What are the three types of stimulus frequency?

Answer 20

Question 22

Is any force produced by simple twitches?

Answer 22

No, there is no sustained activation of muscle

Question 23

What is responsible for the strength changes in the first 8 wks? After that?

Answer 23

1st 8 wks: neural factors

After 8 wks: hypertrophy factors

Question 24

What is the “size principle”?

Answer 24

Question 25

What is the conversion of muscle fibers as a result of inactivity?

Answer 25

Question 26

What characteristics are favored by short-term, high-intensity exercise?

Answer 26

Question 27

What is the purpose of strength/resistance training in the elderly

Answer 27

Maintaining some ballistic muscle strength and muscle mass in order to catch self if they’re going to fall

Question 28

What is the order in which muscle fibers are activated?

Answer 28

Small muscle fibers must fire before the large muscle fibers. If the CNS knows that it needs a larger force, it can speed up the recruitment process.

Question 29

How does more sarcomeres in series affect muscle force?

Answer 29

Same force over a greater distance