Lecture 30

Question 1

What causes an adaptation?

Answer 1

The net effect of many different pathways in response to an activity

Question 2

What is the difference between muscle activation in resistance/endurance exercise and electrical stimulation?

Answer 2

Endurance/Resistance exercise may not stimulate all muscle fibre types (ie. hennemenns size principle) if the intensity is low enough.
Electrical stimulation activates all muscle fibres.

Question 3

What is a problem with adaptation to physical activity?

Answer 3

Its hard to obtain, and easy to lose.
Increasing enzyme activity/concentration is very slow to increase (months) and drop very rapidly when training is stopped.

Question 4

Is it possible to transform muscle fibres from one type to another with electrical stimulation?

Answer 4

Yes

Question 5

Is it possible to transform muscle fibres from one type to another with exercise?

Answer 5

Theoretically, it is possible if it is at a high enough intensity and occurring 24/7 for months.
Not very likely to happen

Question 6

Name the transitions that occur in muscle fibres in response to exercise

Answer 6

Mucles may not transform fibre types, but will have transitions, ie. in between type 2B and type 1.
Subtle changes can be found in the myosin head heavy chain isoforms suited toward the appropriate fibre type

Question 7

What is muscle plasticity?

Answer 7

Muscle isn’t a static tissue, and can change in response to stimuli (exercise etc)

Question 8

What can be said about muscle adaptation to physical exercise between individuals?

Answer 8

Not everyone has the same magnitude of response to physical activity, some more than others.

Question 9

To what physical activity parameters do muscles maximally adapt to?

Answer 9

An exercise that moderately exceeds its capacity, meaning a gradual buildup is needed for maximal response.

Question 10

Describe the general adaptation syndrome (GAS)

Answer 10

Alarm phase: a decrease in performance in response to the onset of exercise, responds with the resistance phase
Resistance phase: Performance rises as it responds to the exercise, such as protein synthesis, mitochondria production, capillaries etc.
Performance plateaus with the resistance phase.
Overtraining causes an exhaustion phase, gradual decrease in performance.

Question 11

Name the limitations to physical adaptation

Answer 11

genetics - everyone responds differently
Not everyone has the same potential to adapt to physical exericse
Is why athletes with the same training have different responses

Question 12

Name some differences between electrical stimulation of a muscle versus voluntary contraction

Answer 12

Voluntary
muscle tension can be varied across the active motor units - produces fine or smooth movements
muscles are recruited according to size and are activated asynchronously
Electrical
Activation patterns ceased, all muscles contract at the same time

Question 13

What are the advantages of electrical stimulation?

Answer 13

-standardised - adaptive response occurs in a reproducible manner
-maximum potential of the muscle is induced (all fibres recruited at once)
-can target a single muscle to minimise systemic effects
-muscle damage is not induced (rat models only)
Allows a clean way of investigating muscle adaptation

Question 14

Describe overloading

Answer 14

When a system or tissue is challenged with a stimuli to which it is unaccustomed
Over time, it will adapt to this stimuli, however, only muscles involved will adapt.

Question 15

Describe some effects of low intensity but long duration exercise on a muscle (endurance)

Answer 15

increased capillary density and more mitochondria production and capacity, as well as central and peripheral circulation adaptation and increased CO

Question 16

What is the effect of endurance exercise on fibre composition

Answer 16

little to no change in fibre size
fibres will not switch types
subtle changes among fast fibre subtypes (2B -> 2A)
chronic training can recruit 2B much faster

Question 17

What is the effect of endurance exercise on mitochondria?

Answer 17

increased mitochondria capacity to produce ATP
increased number, size and efficiency
increased oxidative enzyme activity
release of FFA, shift to reliance on fat for ATP

Question 18

What is the relationship between mitochondrial enzyme activity and maximal oxygen uptake?

Answer 18

Linear increase

anaerobic enzyme activity decreases however

Question 19

Describe the adaptations of resistance exercise

Answer 19

Hypertrophy increase

Atrophy decrease

Question 20

What can be said about fibre numbers in muscle?

Answer 20

They are fixed from birth

Question 21

What occurs during chronic hypertrophy?

Answer 21

increase in the size of individual fibres if gradual progression is used

Question 22

What is hyperplasia?

Answer 22

An increase in fibre number

Question 23

Why does muscle power lag behind muscle size?

Answer 23

In early training, most of the improvements to strength/power is due to neural drive, recruiting muscle fibres optimally.
Over time, once the adaptation sets in, the power improvement decreases, but hypertrophy occurs.

Question 24

What is the effect of steroids on hypertrophy, neural drive and power?

Answer 24

An increase in both strength and hypertophy is seen, but neural drive is unaffected.

Question 25

What is needed to elicit an increase in strength?

Answer 25

The muscle must be challenged above its maximal capacity to elicit adaptation to that exercise.

Question 26

Describe two possibilities for hypoplasia

Answer 26

A heavily hypotrophied fibre splits into two or more daughter cells as its too big
Or
Satellite cell proliferation after muscle damage

Question 27

Fact

Answer 27

Japanese quail were found to have increased fibres post resistance exercise on their wings, suggesting hyperplasia is possible

Question 28

Describe the experiment that suggests muscle fibres split in hyperplasia

Answer 28

A muscle fibre cross section is followed down gradually until it is seen to split into two.

On a different note, getting a cross section of a muscle, before and post exercise and counting fibre numbers isnt sufficient as only a small cross section of a much larger muscle can be obtained

Question 29

Why are individualised training programs important?

Answer 29

Everyone responds a little differently to exercise

Question 30

What are the 5 variables of resistance exercise training protocol?

Answer 30

Choice of exercise
Order of exercise
Intensity
Number of sets
Length of rest period between sets

Question 31

What is periodisation?

Answer 31

Gradual cycling of specificty, intensity and volume to achieve peak performance
critical for sporting success