Lecture 33 - Muscle plasticity: exercise and adaptation

Question 1

true or false

with endurance exercise training only part of the muscle is being used

Answer 1

true

Question 2

true or false

intensity determines which motor units are recruited

Answer 2

true

Question 3

With electrical stimulation all of the fibres are activated regardless of fibre type

Nevertheless, adaptive changes during physical training are qualitatively similar to ….

Answer 3

those during electrical stimulation

Question 4

The adaptations during training are ____and _____ reversible

Answer 4

easily and rapidly reversible

there is a fast decline of these activities within a few week of stopping training

Question 5

the extent of skeletal muscle adaptations depends upon:

Answer 5

the mode, frequency, intensity and duration of the stimulus

Question 6

What are the limitations to exercise adaption?

Answer 6

genetics

we are not all created equal with the same adaptive potential for exercise

explains why athletes that exercise under identical training conditions often show different levels of improvement

Question 7

What are the advantages of electical stimulation?

Answer 7

standardised model - adaptive responses occur in a reproducible well-defined manner

elicits maximal ladaptive potential of the muscle

adaptations occur in a shorter period of time compared with voluntary activity

adaptations restricted to target muscle; therefore minimise systemic effects

does not induce muscle damage in rodents, allowing for a ‘‘clean’’ investigative model

Question 8

Principles of training

What is overload?

Answer 8

a system of tissue must be challenged with an intenity, duration or frequency of the exercise to which it is unaccustomed

over time the tissue or system adapts to this load

Question 9

What is specificity?

Answer 9

the training effect is limited to the muscle fibres involved un the activity

the muscle fbre adapts to the type of activity (SAID)

mitochondrial and capillary adaptations to endurance training

contractile protein adaptations to resistance exercise training

Question 10

What are the adaptations of skelelal muscle to endurance training?

Answer 10

changes to central and peripheral circulation

CO, muscle blood flow

muscle metabolism

muscle respiratory capacity

Question 11

What are the fibre composition changes in endurance training?

Answer 11

little or no change in fibre size

generally little or no change in fibre type proportions

subtle change among fast fibre subtypes: IIB –> IIA or intermediates

chronic training may recruit IIB (glycolytic) fibres in a manner normally expected of the IIA fibres

Question 12

How is oxygen delivery enhanced in endurance training?

Answer 12

capillarisation

15% increase in number of capillaries after 8 weeks training

greater exchange of gases (and waste) and fuels between blood and working muscles

Question 13

How is energy production enhanced in endurance training?

Answer 13

Increase in mitochondrial capacity to produce ATP

number, size and efficiency of mitochondria increases

oxidative enzyme activity: SDH, CS are increase

release of FFA, shift to a reliance on fat for ATP production

Question 14

What adaptations in resistance fatigue?

Answer 14

hypertrophy - increase in size of muscle fibre

Question 15

muscle size generally correlated with ___

Answer 15

strength

tempting to conclude that cause-effect relation ships, but is it that simple?

Question 16

What is hyperplasia?

Answer 16

an increase in the number of muscle fibres

doesn’t contribute much to increase in size

Question 17

most of the hypertrophy that we get with resistance training is due to..

Answer 17

an increase in the size of the indivudual fibres

but also increases in myofibrils and filaments, connective tissue

Question 18

True or false

The greatest change accompanying strength training can be seen in the exercise itself rather than objective assessments of strength or size

Answer 18

true

improvement in exercise performance (how much weight) is the best way to tell

Question 19

What neural mechanisms are important in muscle strength changes?

Think about motor units.

Answer 19

First changes in muscle strength during training are the result of altered neural drive

large, fast MUs are only recruited at higher forces

training can facilitate recruitment of these large and fast MUs

changes int the pattern of MU stimulation or synchronisation of MU firing

Question 20

the major determinant of strength is muscle size, or more , specifically ….

Answer 20

muscle cross-sectional are

variation in strength between people can be explained by difference in muscle size

Question 21

true or false

As an adaptation to resistance training - all muscle fibres get bigger because they are all recruited in consecutive order to produce high levels of forces

(what can happen with advanced lifters)

Answer 21

true

in advanced lifters the DNA might adapt to allow these athletes to recruit some MUs not in consecutive order

i.e by recruiting larger ones first to help with greater production of power or speed in a movement

Question 22

Can fibre hyperplasia occur in muscle as a consequence of strngth training?

Answer 22

two possible ways:

splitting of hypertrophied fibres into two or more daughter fibres

satellite cell proliferation following muscle damage

Question 23

cats and birds have exhibited _______.

Answer 23

hyperplasia

Question 24

Each person resposnds ____ to each training program

Answer 24

differently

an individualised training program is needed to address the specific needs and responses of the athlete

the magnitude of physiological or performance gain is related to the size of an athletes adaptation window

Question 25

true or false

exercise training programs need to change and provide variation to keep the exercise stimulus effective in eliciting positive changes or maintaining sport fitness

Answer 25

true

training for peak athlete performance is different from training for optimal health and fitness:

training intensities, frequencies and volumes

Question 26

what are five acute program variables of a resistance exercise protocol:

Answer 26

choice of exercise

order of exercise

resistance or intensity

number of set

length of rest between sets

Question 27

For sporting success, ______ is critical for peaking for specific events

Answer 27

periodisation

prep, transition, competition phases