Week 9- effects of resistance training

Question 1

What is muscular strength?

Answer 1

maximal force that a muscle group can generate
-1 repetition maximum

Question 2

What is muscular endurance?

Answer 2

ability to make repeated contractions against a submaximal load

Question 3

What is high-resistance training?

Answer 3

-6-10 reps till failure
-results in strength increase

Question 4

What is low-resistance training?

Answer 4

-30-40 reps till failure
-results in increased endurance

Question 5

What is sarcopenia?

Answer 5

loss in muscle mass

Question 6

What occurs to the muscles as we age?

Answer 6

-loss of muscle mass
-atrophy type 2 fibres
-loss of motor neurons
-reduced number of both type 1 and 2 fibres

Question 7

What does resistance training promote?

Answer 7

Muscle hypertrophy

Question 8

What is responsible for early gains in strength?

Answer 8

Neural adaptations

Question 9

What are the strength gains during the first 8 weeks of training due to?

Answer 9

CNS adaptations

Question 10

What shows the CNS adaptations in the early stages of training?

Answer 10

-strength increases of training whilst no change in fibre size
-training in one limb results in strength in untrained limb
-

Question 11

What are the adaptations that occur in the muscle fibres that occurs later on in the training?

Answer 11

-increase muscle fibre specific tension
-increase muscle mass

Question 12

What are the neural adaptations from resistance training?

Answer 12

-increased neural drive
-increase in number of motor units recruited
-increase in firing rate of motor units
-increase motor unit synchronisation
-improved neural transmission across neuromuscular junction
-Changes in rate of agonist and antagonist co-activation

Question 13

What is the mechanism seemed to be linked with training-induced increase in specific tension in type 1 fibres?

Answer 13

increase in calcium sensitivity

Question 14

what does an increase in calcium sensitivity cause?

Answer 14

greater number of cross-bridge bound to actin

Question 15

What is the result of a greater number of cross-bridge binding to actin?

Answer 15

-more force per motor unit
-strength gains independent of muscle growth

Question 16

What is hyperplasia?

Answer 16

increase in number of muscle fibres

Question 16

What causes muscle hypertrophy?

Answer 16

increased muscle proteins (actin and myosin)

Question 16

What is the definition of muscle hypertrophy?

Answer 16

increased cross-sectional area of muscle fibres

Question 17

What do type IIx muscle fibres change to with resistance training?

Answer 17

Type IIa

Question 18

How does muscle growth occur?

Answer 18

protein synthesis exceeds the rate of protein breakdown

Question 19

How many weeks must protein synthesis exceed the rate of protein breakdown to achieve significant fibre growth?

Answer 19

3 or more weeks

Question 20

What are the key factors that contribute to resistance-training induced increases in muscle protein synthesis?

Answer 20

-mRNA increases resulting in protein synthesis at the ribosome
-ribosomes increase in number and increase muscle synthesis capacity
-activation of protein kinase ‘mechanistic target of rapamycin’ (mTOR) is the key factor in accelerating protein synthesis following a bout of resistance training

Question 21

what are the two signalling molecules that stimulate mTOR activation?

Answer 21

-phosphatidic acid (PA)
-Ros homolog enriched in brain (Rheb)

Question 22

What activates sarcolemmal mechanoreceptors that activate extracellular signal-regulated kinase (ErK)?

Answer 22

muscle contractions

Question 23

What does active ErK inhibit?

Answer 23

TSC2

Question 24

What is TSC2?

Answer 24

a inhibitor of Rheb

Question 25

How does resistance training activate mTOR?

Answer 25

By synthesising PA and removing the TSC2 inhibition of Rheb

Question 26

What hormones are linked to mTOR activation and have the potential to increase muscle protein synthesis?

Answer 26

insulin-like growth factor-1 (IGF-1)

Question 27

What effects does resistance training have on IGF-1 and growth hormone?

Answer 27

small increases in circulating levels

Question 28

What are satellite cells?

Answer 28

Stem cells located between the sarcolemma and basal lamina

Question 29

What effects does resistance training have on satellite cells?

Answer 29

activates the satellite cells to divide and fuse with adjacent muscle fibres to increase myonuclei

Question 30

What effect does resistance training on myonuclei?

Answer 30

increase in myonuclei results on a constant ratio between number of myonuclei and size of muscle fibre

Question 31

What is the impact of the addition of new myonuclei to fibres?

Answer 31

support increased protein synthesis in large muscle fibres

Question 32

What % of muscle mass difference between individuals is due to genetic variation?

Answer 32

80%

Question 33

How many genes are major contributors to muscle mass?

Answer 33

47

Question 34

How are hypertrophy-linked genes activated?

Answer 34

resistance training linked t mTOR pathway

Question 35

What does the stopping of resistance training cause?

Answer 35

muscle atrophy and loss of strength

Question 36

Compared to endurance training, is the rate of detraining faster or slower for resistance training?

Answer 36

slower

Question 37

What is 'muscle memory'?

Answer 37

ability for rapid recovery after the stopping of resistance training

Question 38

What is muscle memory due to?

Answer 38

resistance-training induced increase in myonuclei in trained fibres that are not lost due to retraining

Question 39

How much do muscle fibres reduce in size 20-30 days of muscle inactivity?

Answer 39

20-30%

Question 40

What is the conservation of muscle mass dependent upon?

Answer 40

Balance between protein synthesis and rate of protein breakdown

Question 41

What does increased radical production promote?

Answer 41

muscle atrophy during prolonged inactivity by depressing protein protein synthesis and increasing degradation