Lesson 4

Question 1

What are the 5 factors that contribute to muscle mass development/strength?

Answer 1

• genetics
• NS activation
• physical activity
• nutritional activity
• endocrine influences
• environmental factors

Question 2

What are the 3 muscle adaptations that increase strength of muscles?

Answer 2

• hypertrophy: PCSA and hyperplasia
• increase proportion of Type II muscle fibers
• myofilament packing: b/c increase number of myofilaments means increased crossbridges

Question 3

Describe how PRT affects hypertrophy and what else you need to train w/ new muscular size and why.

Answer 3

• PRT creates adaptive response in muscle, b/c it creates more efficient translation of mRNA to mediate stimulation of myofibrillar protein synthesis
• need aerobic training b/c number of mitos stays the same during PRT, but protein numbers have increased

Question 4

Is it hypertrophy or hyperplasia in muscles?

Answer 4

hypertrophy - result of increase in fiber size, not number

Question 5

What fiber type transformation can PRT have on muscles?

Answer 5

Type IIB - high F, but decrease oxidative -

to Type IIA (slightly less F, but increase oxidative, so less fatiguable)

Question 6

Why can you only transform within same fiber type?

Answer 6

• the type of motor N innervating the muscle fiber dictates the muscle fiber’s characteristics
• N cross-innervation and artificial E-stim can reverse metabolic and contractile profiles of muscle fibers

Question 7

How do neural and hypertrophic factors contribute to strength gains?

Answer 7

neural adaptations: 0-4 weeks

hypertrophic adaptations: 6+ weeks

Question 8

What are the 5 neural changes in strength?

Answer 8

increased:

• number of motor units recruited
• firing rate of MU’s
• MU synchronicity
• activation of synergist muscles
• inhibition of antagonists

Question 9

Does RT reduce fat or increase CV fitness?

Answer 9

• it can reduce percent of body fat when you increase muscle mass, but doesn’t reduce the amount of fat
• no change in CV

Question 10

What is EPOC?

Answer 10

in exhaustive exercise, the exercise O2 requirement significant exceeds actual exercise O2 consumption, so even during recovery need to replace depleted O2 deficit and therefore we use increased O2 after exercise for about 3 hours
-we use ATP w/o O2 in phosphagen system during exercise, so we replace the used ATP afterwards by increased O2 consumption

Question 11

What are factors that contribute to EPOC?

Answer 11

• resynthesize ATP and convert lactate to glycogen
• oxidize lactate in E metabolism
• restore O2 to myoglobin
• thermogenic effect of increasing core temp and hormones
• effects of increased HR, ventilation

Question 12

How does EPOC affect metabolism?

Answer 12

can have increased metabolism for about 38 hours after RT

Question 13

What accounts for majority of strength gain in younger and older novices?

Answer 13

learning and familiarization (5-10%) due to neural adaptation

Question 14

How many calories do you burn a min with exercise?

Answer 14

6-10 kcal

Question 15

What does training at fast and slow velocities improve?

Answer 15

slow: improvement across all speeds
fast: most improvements only at high speeds

Question 16

Why is there neural inhibition? What its derived from?

Answer 16

• may be a protective reflex

- derived from unpleasant past experience, overly protective home environment, fear of injury

Question 17

What are different techniques to increase supramaximal performance by increasing motor N recruitment?

Answer 17

• motivation
• encouragement
• excitement
• disinhibitory drugs
• hypnotic suggestion (most effective)

Question 18

How are NMJ’s adapted in endurance training of animals?

Answer 18

• increase size and complexity

- increase presympathetic ACh stores and isozymes of ACh delays NMJ fatigue

Question 19

What does an EMG do?

Answer 19

study neuromuscular adaptations and reflects both quality/quantity of electrical activity generated

Question 20

In early and late stages of RT program, how does EMG respond? What about w/ eccentric vs concentric?

Answer 20

early stages: EMG will increase due to neural adaptations
late stages: EMG doesn’t increase b/c hypertrophic
eccentric: about 25% less than EMG for same absolute workload w/ concentric contraction, because use less ATP

Question 21

What are different muscle fiber type classifications?

Answer 21

-red = myoglobin
Type I: slow twitch, low tension and fatigue resistant
Type IIA: fast twitch, mod force and fatigue resistant
Type IIB: fast twitch, high force and high fatigue

Question 22

What is the size principle of muscle fiber recruitment?

Answer 22

-slow oxidative MU’s (Type I) are recruited first b/c require less excitation to reach threshold

Question 23

What type of contraction uses less ATP?

Answer 23

eccentric

Question 24

What is the importance of eccentric muscle contraction?

Answer 24

• low metabolic cost
• increased strength production and hypertrophic adaptations
• easier to perform
• implications for rehab

Question 25

What is myofibrillar disorganization and what happens to F transmission?

Answer 25

• breakage of cytoskeletal proteins at the Z-disc

- lose some F b/c physical change to sarcomeres make them weaker

Question 26

Why do you feel DOMS?

Answer 26

• microscopic tears
• osmotic pressure changes = fluid retention
• muscle spasms
• overstretching CT
• acute inflammation
• altered calcium regulation

Question 27

What is exertional rhabdomyolysis?

Answer 27

myoglobin spills over from blood to urine- causing renal failure
-Coca-Cola colored urine!

Question 28

When does DOMS usually occur and how long does it last?

Answer 28

high-intensity or long-term eccentric/plyo

-peaks at 36-48 hours and last 3-4 days

Question 29

What are 2 mechanisms of muscle damage?

Answer 29

1) -early in exercise (A b/c oxidative fibers not as stiff
2) -same first step
- mitos lose calcium buffering capacity b/c unable to regenerative ATP
- increase intracellular calcium results in activation of calcium-activated proteases and lysozymes
- –explains importance of oxidative capacity of muscles

Question 30

What happens in the SR in muscle damage?

Answer 30

• decrease in pH
• increase ADP, Pi
• altered ionic balance and temp
• -all factors may decrease calcium uptake and release, resulting in high calcium in cytosol, leading to decrease F capacity and soreness

Question 31

What are markers for muscle damage?

Answer 31

creatine kinase
myoglobin
troponin
LDH
alanine aminotransferase

Question 32

What is pain from in eccentric exercises?

Answer 32

inflammatory response stimulating very small sensory N endings in muscle and muscle spindles

Question 33

How does a single exercise bout effect subsequent exercise?

Answer 33

existing muscle soreness doesn’t exacerbate subsequent muscle damage or impair process, in fact it can protect against new soreness for up to 6 weeks

Question 34

How much strength loss can occur after 1 bout of eccentric exercise in novice?

Answer 34

25-50% decrease for several weeks

Question 35

What is the “popping sarcomere” theory?

Answer 35

• sarcomeres naturally rest at slightly different lengths, which means some longer sarcomeres have less filament overlap and thus generate decreased F compared to shorter counterparts
• when long sarcomere “pop” apart, replaced with 2 short sarcomeres in series to help prevent future muscle damage

Question 36

What is purpose of placing sarcomere in parallel or in series?

Answer 36

• in parallel: increases F

- in series: protects against muscle damage from tension