LECTURE 28

Question 1

What determines which motor units are recruited?

Answer 1

Intensity

Question 2

What happens with electrical stimulation?

Answer 2

All fibre types, regardless of type, are recruited

Question 3

When will muscles adapt optimally?

Answer 3

When exercise moderately exceeds their capacity

Question 4

What happens when we challenge the muscle?

Answer 4

Initial alarm phase

Question 5

What happens after we have challenged the muscle?

Answer 5

Resistance phase - more mitochondria and capillaries to combat the challenge - system plateaus because body has adapted to cope with challeneg

Question 6

What happens if we challenge the system too much?

Answer 6

Exhaustion phase - cannot respond to challenge, breakdown not protein

Question 7

How can muscle tension be varied?

Answer 7

By varying the number of active motor units

Question 8

How are motor units activated in voluntary muscle contraction?

Answer 8

According to size principle, activated synchronously

Question 9

How are motor units activated in electrical stimulation?

Answer 9

Voluntary activation patterns abolished, all motor units activated with same impulse pattern

Question 10

What are the advantaged of electrical stimulation?

Answer 10

Maximal adaptive potential of muscle, adaptations in short time, adaptations restricted to target muscle, no muscle damage

Question 11

What is specificity?

Answer 11

Training effect is limit to muscle fibres involved in activity, muscle fibre adapts specifically to the type of activity

Question 12

What are the adaptations with resistance and endurance training?

Answer 12

E: mitochondrial and capillary adaptations (changes to central and peripheral circulation, CO, muscle blood flow, metabolism and reap capacity)
R: contractile protein adaptations

Question 13

What happens to fibre composition with endurance training?

Answer 13

Load on muscle needs to be high for fibre size change - no conversion of fibres

Question 14

What happens to oxygen delivery with endurance training?

Answer 14

Increase capillaries around muscle to meet oxygen demand, 15% increase after 8 weeks, greater gas exchange between blood and muscle

Question 15

What happens to energy production with endurance training?

Answer 15

Increase ATP production capacity of mitochondria, number, size and efficiency of mitochondria increased, oxidative enzyme activity increased, FFA for ATP production

Question 16

What happens when oxygen uptake increases?

Answer 16

SDH (succinate dehydrogenase) activity increases

Question 17

Who has higher SDH activity?

Answer 17

Trained endurance people

Question 18

Who has greater anaerobic enzymes?

Answer 18

Trained sprint athletes

Question 19

What are the adaptations of skeletal muscle to resistance training?

Answer 19

Hypertrophy, increased fibre size (90% hypertrophy, 10& hyperplasia), increase myofibrils, improvement in exercise performance (GREATEST INCREASE)

Question 20

What are the first changes in muscle strength a result of ?

Answer 20

Neural drive - training can facilitate recruitment of fast motor units earlier

Question 21

What is task specificity?

Answer 21

Improvement in the coordination of different muscle groups

Question 22

What is the major determinant of strength?

Answer 22

Muscle size/CSA

Question 23

What are the two possibilities for hyperplasic response?

Answer 23

• Splitting of hypertrophied fibres into two or more daughter fibres (splits because it is too big to receive enough nutrients to survive)
• Satellite cell proliferation following muscle damage

Question 24

What are the animal model increases in muscle fibres?

Answer 24

Bird - 80%
Cat - 9%
Rat - 14%

Question 25

How do we determine whether true hyperplasia has occurred?

Answer 25

Looking at a long length of fibre to track its path - see whether the fibre has split or proliferated

Question 26

What happens with changing load/reps?

Answer 26

high load, low reps = strength/power

low load, high reps = local muscular endurance

Question 27

What is periodisation?

Answer 27

Gradual cycling or specificity, intensity and volume of training to achieve peak performance

Question 28

What should a novice athlete training program be?

Answer 28

start with high volume and moderate intensity, and reduce volume over time whilst increasing intensity and technique

Question 29

What should an advanced athlete training program be?

Answer 29

start with high volume and intensity (continuously cycling) and low technique, over time maintain volume and intensity and increase technique, then reduce all for rest period