Module 4: LAST LECTURE!!!

Question 1

What is the muscle length relationship?

Answer 1

• referring to the length of your sarcomere from z-line to z-line

the amount of overlap between your think and thin filaments will dictate how much force you can generate

Question 2

What is the optimal muscle length?

Answer 2

maximum amount of force your muscle can generate

• all of your myosin heads are able to interact with a actin filament

Question 3

What happens when we make our sarcomere longer?

Answer 3

• this is where we increase the distance of out z-discs
• the amount of force our muscle will generate will drop due to the less overlapping of the actin and myosin filaments

Question 4

True or False
Lengthening the muscle will cause a decrease in the amount of force generation

Answer 4

True, because we decrease the amount of potential cross-bridges that can form

Question 5

What happens when we make our sarcomere shorter?

Answer 5

• decrease the distance form z-line to z-line
• the amount of force our muscle will generate will drop due to the thin filaments “bumping” into one another altering the structural organization of our sarcomeres
  = decreases the number of available sites that you can from cross-bridges

Question 6

True or False
Shortening the muscle will cause a decrease in the amount of force generation due to the overlapping thin firmament, limiting the number of active site available for cross-bridges to form

Answer 6

True

Question 7

What stops us from getting to an extreme lengthening or an a extreme shortening of the muscle?

Answer 7

our joints

Question 8

In what case/scenario will your H-zone disappear?

Answer 8

when your muscles are shortened to the point where your actin filaments are bumping into each other

Question 9

What are the 2 kinds of muscle contractions?

Answer 9

1. Isotonic
2. Isometric

Question 10

What is muscle tension?

Answer 10

the force exerted BY a muscle contraction on an object

• aka the amount of force a muscle is producing

Question 11

What is a muscle load

Answer 11

the force exerted ON a muscle by an object

• aka the object is implementing “x” amount of force on a muscle when we for instance are carrying it

Question 12

True or False
The muscle tension is the tension in the muscle fibres itself?

Answer 12

true

Question 13

True or False
The amount of force that the object is placing on muscle fibres is referred to as the muscle load?

Answer 13

True

Question 14

The balance between muscle tension and muscle load will dictate what?

Answer 14

the kind of muscle contraction that occurs

• whether the muscle shortens or lengthens

Question 15

If the muscle tension is greater than the load what will happen?

Answer 15

shortening

Question 16

If the muscle tension is lesser than the load what will happen?

Answer 16

lengthening

Question 17

What is an isometric contraction?

Answer 17

no change in muscle length

Question 18

What is a isotonic contraction

Answer 18

where shortening or lengthening occurs in the muscle

• constant load, tension in the muscle

Question 19

Shortening can be referred to as?

Answer 19

concentric contractions

Question 20

Lengthening can be refereed to as?

Answer 20

eccentric contraction

Question 21

iso means?

Answer 21

same

Question 22

tonic means?

Answer 22

tension

Question 23

Metric means?

Answer 23

length

Question 24

What is the force velocity relationship?

Answer 24

how much force a muscle can produce relative to what velocity that muscle is contracting at

*Referring to the shortening phase of the muscle

Question 25

What would an isometric contraction look like relative to the force velocity relationship graph?

Answer 25

where velocity is = 0 - not change on muscle length

Question 26

When can we produce the maximum force?

Answer 26

at an isometric contraction - where the velocity is 0

Question 27

What is the unloaded shortening velocity? (Vmax)

Answer 27

the fastest velocity that your muscles are able to shorten at

Question 28

True or False We will never experience the unloaded shortening velocity unless in a lab?

Answer 28

true

Question 29

What is power?

Answer 29

force x velocity

Question 30

What is your peak power of the muscle?

Answer 30

maximum amount / highest energetic contraction we can produce

Question 31

When can maximum power be produced?

Answer 31

when theres an optimal load and velocity relationship

Question 32

What are the 3 fibre types in humans?

Answer 32

1. Type 1 (I) - slow twitch 2. Type 2A (IIA) - fast twitch 3. Type 2X (IIX) - fast twitch

Question 33

True or False Your myosin ATPase, will dictate whether we have a slow or fast twitch

Answer 33

True

Question 34

Fast fatigue refer to?

Answer 34

Type 2X

Question 35

Fast fatigue resistance refer to?

Answer 35

Type 2A

Question 36

slow fibres refer to?

Answer 36

Type 1

Question 37

In what instance can we get changes in our muscle fibre variations?

Answer 37

spinal cord injuries, all your slow twitch fibres turn onto fast twitch fibres

Question 38

come back too!!! What are the 2 OVERALL factors changing the whole-muscle tension in the muscle? and other sub-factors?

Answer 38

1. Change the number of fibres that are contracting - # of motor unit recruitment - # of muscle fibres per motor unit - # of muscle fibres available to contract - size of muscle fibres (# of muscle fibres within a muscle) - presence of disease - extent of recovery from injury 2. Change the tension developed by each contracting fibre - frequency and activation rates - twitch summation - length of fibre - length-tension relationship - Extent of fatigue - fibre type - duration of activity - Thickness of fibre

Question 39

What is the number 1 factor that is going to dictate how much force is actually being generated in the muscle?

Answer 39

the size of the muscle fibre - the more myofibrils in the muscle fibres the more cross-bridges can form overall

Question 40

is there more slow twitch or fast twitch motor units overall in our muscles?

Answer 40

slow twitch

Question 41

What kind of energy is used for type 1 muscle fibres?

Answer 41

Slow oxidative

Question 42

What kind of energy is used for type 2A muscle fibres?

Answer 42

fast oxidative glycolytic and some slow oxidative

Question 43

What kind of energy is used for type 2X muscle fibres?

Answer 43

fast oxidative glycolytic

Question 44

What are the structural properties of the muscle fibres?

Answer 44

- diameter - motor units per muscle - SR development

Question 45

What are the diameter, motor units per muscle and SR development of the slow, fast A and fast X twitches?

Answer 45

Slow: diameter = small motor units per muscle = more, smaller SR development = poor Fast A: diameter = large motor units per muscle = fewer, larger SR development = intermediate Fast X: diameter = large motor units per muscle = fewer, larger SR development = high

Question 46

What are the functional properties of the muscle fibre?

Answer 46

- twitch time - relaxation time - force production - fatiguability - sensitivity to recruitment

Question 47

What are the twitch time, relaxation time, force production, fatiguability and sensitivity to the recruitment of the slow, fast A and fast X twitches?

Answer 47

Slow: twitch time = slow relaxation time = slow force production = low fatiguability = fatigue-resistant sensitivity to recruitment = high Fast A: twitch time = fast relaxation time = intermediate force production = intermediate fatiguability = fatigue sensitivity to recruitment = intermediate Fast X: twitch time = fast relaxation time = fast force production = high fatiguability = most fatigable sensitivity to recruitment = low

Question 48

What are the metabolic properties of the muscle fibre?

Answer 48

- red colour - myosin-ATPase activity

Question 49

What are the red colour and the myosin-ATPase activity of the slow, fast A and fast X twitches?

Answer 49

Slow: red colour = dark myosin-ATPase activity = low Fast A: red colour = dark myosin-ATPase activity = intermediate Fast X: rec colour = pale myosin-ATPase activity = high