Chapter 13/14/20: The Physiology of Training

Question 1

describe the principle of overload

Answer 1

increased capacity of a system in response to training above the level to which it is accustomed

Question 2

what factors can contribute to overload?

Answer 2

intensity, duration and frequency

Question 3

what does too much overload lead to? common issue in which group?

Answer 3

overtraining or overreaching, which is a common issue with elite athletes

Question 4

describe the principle of reversibility

Answer 4

when training is stopped, the training effect is quickly lost

Question 5

describe the principle of specificity

Answer 5

training effect is specific to:
1) muscle fibers recruited during exercise
2) type of contraction (eccentric, concentric, isometric)
3) energy system involved (aerobic vs. anaerobic)

Question 6

how does the VO2 max for an athlete during their sport specific activity compare to their VO2 max on a treadmill?

Answer 6

VO2 max during sport specific activity were as high or higher than their VO2 max on a treadmill

Question 7

is there a difference between men and women’s responses to training programs?

Answer 7

no, exercise prescriptions should be individualized

Question 8

how does initial fitness level effect training improvement?

Answer 8

training improvement is always greater in individuals with lower initial fitness levels

Question 9

how do genetics influence an individual’s response to training? evidence?

Answer 9

genetics play an important role, evidence with identical twin study: ten sets of identical twins went through the same training program- there was a similarity in the response of each pair, but improvement in VO2 max varied from 0-40%

Question 10

how does training affect the VO2 max of high responders (genetically)?

Answer 10

high responders possess a relatively high untrained VO2 max which increases significantly with training

Question 11

how does training effect the VO2 max of low responders (genetically)?

Answer 11

low responders possess a relatively low untrained VO2 max which does not increase significantly with training

Question 12

how do genetics effect anaerobic training?

Answer 12

anaerobic training is more genetically determined, training can only improve anaerobic performance to a small degree

Question 13

why is anaerobic capacity more genetically determined than aerobic capacity?

Answer 13

anaerobic capacity is largely dependent on fast (type IIx) fibers which are determined early in development

Question 14

how does muscle fiber type change with aerobic training?

Answer 14

reduction in cross-sectional area of fast fibers and increase in cross-sectional area of slow fibers

Question 15

how does capillary density change with aerobic training? consequence?

Answer 15

increased number of capillaries surrounding muscle fibers which enhances oxygen diffusion and improves removal of wastes

Question 16

how does myoglobin content change during aerobic training? consequence?

Answer 16

increases muscle myoglobin content by 75-80% which supports the muscle’s increased capacity for oxidative metabolism after training

Question 17

how does muscle mitochondria content change with aerobic training?

Answer 17

doubles within 5 weeks of training, then plateaus

Question 18

what types of mitochondria are increased with endurance training?

Answer 18

both subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria

Question 19

what does increasing volume of mitochondria in muscle fibers result in?

Answer 19

improved oxidative phosphorylation capacity and ability to utilize fat as fuel

Question 20

how does aerobic training affect mitochondrial turnover?

Answer 20

training increases the breakdown of damaged mitochondria and replacement with healthy mitochondria (increases turnover)

Question 21

term for breakdown of damaged mitochondrial

Answer 21

mitophagy

Question 22

how does increased mitochondrial volume affect ADP levels? what does this result in?

Answer 22

increased mitochondrial volume decreases cytosolic [ADP] due to increased ADP transporters in mitochondrial membrane, which results in less lactate and H+ formation and less PC depletion

Question 23

how does endurance training affect the O2 deficit at the onset of work? how?

Answer 23

endurance training reduces the O2 deficit at the onset of work; because more mitochondria can increase oxidative capacity

Question 24

does aerobic training affect the absolute amount of oxygen consumed at a given work rate once steady state is reached?

Answer 24

no, does not change amount of oxygen consumed at a given workload once steady state is reached (still costs the same amount of oxygen)

Question 25

how does low muscle glycogen influence endurance training-induced adaptations?

Answer 25

low muscle glycogen induces higher activation of PGC-1alpha (signaling molecule) which leads to increased protein synthesis and mitochondria formation

Question 26

2 approaches to create low muscle glycogen, what may be a disadvantage to each?

Answer 26

1) restrict dietary carbs: may cause fatigue and limit training 2) train twice per day (every other day): second training session with lower muscle glycogen (lower performance)

Question 27

effect of exercise duration on muscle fuel source

Answer 27

increased exercise duration increases fat utilization and decreases carb utilization

Question 28

how do endurance trained athletes compare to untrained individuals with regards to fuel source?

Answer 28

endurance trained athletes use more fat and less carb than less-fit athletes during prolonged exercise at the same intensity

Question 29

2 methods by which endurance training affect free-fatty acid and glucose utilization?

Answer 29

1) increased mitochondrial number —> increased beta oxidation enzymes 2) increased capillary density —> slows blood flow in muscle and increased FFA transporters —> increased uptake and utilization of FFA —> spares plasma glucose

Question 30

how does increased mitochondrial volume with endurance training improve acid-based balance during exercise? (2 ways)

Answer 30

1) increased mitochondrial number —> increased FFA oxidation and decreased PFK activity —> decreased pyruvate —> decreased lactate and H+ formation —> blood pH maintained 2) increased mitochondrial number —> increased mitochondrial uptake of pyruvate and NADH —> decreased lactate and H+ formation —> blood pH maintained

Question 31

how does endurance training affect the lactate threshold?

Answer 31

with endurance training, the lactate threshold occurs at a higher percentage of one’s VO2 max

Question 32

which is more important in improving VO2 max: intensity or duration?

Answer 32

intensity

Question 33

ideal exercise intensity that shows the greatest improvement in VO2 max

Answer 33

80% of VO2 max

Question 34

what factors determine VO2 max? what equation?

Answer 34

VO2 max is the product of maximal cardiac output and arteriovenous difference (Fick equation) VO2 max = HR max x SV max x max(a-vO2) diff

Question 35

how does cardiac output change with endurance training?

Answer 35

max cardiac output increases with endurance training

Question 36

how does endurance training affect heart size?

Answer 36

cardiac muscle mass and ventricular volume increase as an adaptation to the increased work demand

Question 37

how does endurance training affect resting heart rate?

Answer 37

resting heart rate decreases markedly (bradycardia)

Question 38

how does endurance training affect submaximal and maximal heart rate?

Answer 38

heart rate is lower at any given absolute exercise intensity, but max heart rate typically remains unchanged (or may slightly decrease)

Question 39

how does endurance training affect recovery heart rate?

Answer 39

heart rate returns to resting level much more quickly after an exercise bout than it does before training

Question 40

because heart rate max does not change or decreases, how can there be an increase in VO2 max? (Fick equation)

Answer 40

adaptations in stroke volume max and (a-vO2) difference max

Question 41

how do short duration training programs (approx. 4 months) compare to longer duration training programs (approx. 28 months) in terms of improvements in VO2 max?

Answer 41

with short duration training, the dominant factor in increasing VO2 max is an increase in stroke volume with longer duration training, both stroke volume and a-vO2 increase to improve VO2 max

Question 42

how does aerobic training affect stroke volume?

Answer 42

stroke volume plateaus at a higher workload after training (and may not plateau with elite athletes)

Question 43

3 factors increasing stroke volume

Answer 43

1) increased preload (EDV) 2) increased contractility 3) decreased afterload

Question 44

3 factors increasing end diastolic volume

Answer 44

1) increased plasma volume 2) increased filling time and venous return 3) increased ventricular volume

Question 45

what factor does endurance training specifically change that leads to an increase in stroke volume? when does this effect have a larger influence?

Answer 45

increases total blood volume --> increased plasma volume and increased volume of red blood cells (this effect is larger at higher training intensities)

Question 46

what happens if the change in plasma volume & number of red blood cells isn't exactly proportional?

Answer 46

decreased hematocrit (pseudoanemia) - it looks like the number of red blood cells decreased, but they didn't, the increase in plasma volume was just slightly larger

Question 47

how does endurance training affect ventricular filling?

Answer 47

improves ventricular filling due to bradycardia

Question 48

how does endurance training affect the max (a-vO2) difference?

Answer 48

1) increased muscle blood flow (decreased SNS vasoconstriction at same absolute workload) 2) improved ability of the muscle to extract oxygen from the blood (increased capillary density and increased mitochondrial number)

Question 49

why does the respiratory system NOT usually limit performance?

Answer 49

ventilation can be increased to a much greater extent than cardiovascular function

Question 50

how does endurance training affect lung structure and function at rest? what adaptations does the respiratory system undergo?

Answer 50

no effect on lung structure and function at rest; pulmonary ventilation changes to maximize efficiency

Question 51

how does endurance training affect pulmonary ventilation?

Answer 51

pulmonary ventilation is lower during submaximal exercises and maximal pulmonary ventilation is substantially increased

Question 52

how do females and males compare in max pulmonary ventilation?

Answer 52

males typically have a higher max pulmonary ventilation (they have bigger lungs)

Question 53

during detraining, what is the initial decrease in VO2 max (12 days) due to? do HR and a-vO2 diff change?

Answer 53

decreased max stroke volume; HR and a-vO2 diff remain unchanged

Question 54

during detraining, what is the later decrease in VO2 due to?

Answer 54

decreased max a-vO2 diff

Question 55

why does max a-vO2 diff decrease?

Answer 55

due to decreased mitochondria (no change in capillary density)

Question 56

time course of mitochondrial changes during detraining

Answer 56

mitochondrial adaptations lost very quickly, requires 3-4 weeks of retraining to regain mitochondrial adaptations

Question 57

describe the lack of transfer of training effect

Answer 57

the responses of the cardiovascular, pulmonary, and sympathetic nervous systems are more dependent on the trained state of the muscles involved in the activity than on some specific adaptations in those systems (endurance training on one leg does not transfer to the other)

Question 58

define muscular strength

Answer 58

maximal force a muscle or muscle group can generate (1 rep max)

Question 59

difference between high-resistance training and low-resistance training

Answer 59

high-resistance (6-10 reps until fatigue): results in strength increases low-resistance (35-40 reps until fatigue): results in increases in endurance

Question 60

unlike endurance training, when one arm is exposed to resistance training, a portion of the training is "transferred" to the other arm, why?

Answer 60

neural adaptations

Question 61

2 changes in skeletal muscle size with resistance training

Answer 61

1) hyperplasia: increase in muscle fiber number 2) hypertrophy: increase in cross-sectional area of muscle fibers (due to increased muscle proteins - actin and myosin)

Question 62

what is responsible for early gains (8-20 weeks) in strength?

Answer 62

neural adaptations including: 1) increased number of motor units recruited 2) increased firing rate of motor units 3) increased motor unit synchronization 4) improved neural transmission across neuromuscular junctions 5) increased agonist activity, decreased antagonist activity

Question 63

does hyperplasia occur in humans?

Answer 63

probably not

Question 64

how does resistance training change muscle fiber type?

Answer 64

increase in cross sectional area of all fiber types but there is a shift from fast fibers to slow fibers (shift in cross-sectional area from type IIx to type IIa)

Question 65

why would muscle fiber types shift from type IIx to type IIa during strength training?

Answer 65

increased oxidative capacity allows more energy production over long periods of time (multiple reps for multiple sets - in every sport, even the gym)

Question 66

how does resistance training lead to muscle hypertrophy?

Answer 66

resistance training --> mTOR activation --> protein synthesis --> muscle hypertrophy

Question 67

how does ingesting protein influence muscle protein synthesis?

Answer 67

ingesting protein increases the rate of protein synthesis for both endurance and resistance training

Question 68

how do genetics influence the magnitude of resistance training-induced hypertrophy?

Answer 68

genetics account for 80% of the difference in muscle mass between individuals

Question 69

how does detraining after resistance training affect the muscles?

Answer 69

muscle atrophy due to decreased protein synthesis and increased protein breakdown (muscle takes a lot of energy to maintain)

Question 70

how does the rate of decline of detraining with resistance training compare to that of endurance training?

Answer 70

rate of detraining (strength loss) is slower and recovery of dynamic strength loss can occur more rapidly with retraining

Question 71

why does retraining with resistance training happen much faster than endurance training?

Answer 71

because of muscle myonuclei (stick around)

Question 72

how does combining strength and endurance training affect strength gains?

Answer 72

combining strength and endurance training limits strength gains

Question 73

3 potential mechanisms of why strength gains are limited when you combine endurance and strength training

Answer 73

1) neural factors: impaired neural unit recruitment (limited evidence) 2) overtraining: no direct evidence 3) depressed protein synthesis: endurance training cell signaling can interfere with protein synthesis (strongest evidence)

Question 74

how does endurance training cell signaling interfere with protein synthesis?

Answer 74

endurance training --> increases AMPK --> AMPK inhibits mTOR --> inhibits protein synthesis

Question 75

does concurrent training impair training-induced increases in endurance?

Answer 75

no

Question 76

what should athletes do to avoid decreases in strength with concurrent training?

Answer 76

perform strength and endurance training on alternate days for optimal strength gains, or avoid concurrent training if your sport requires maximal strength

Question 77

describe the "ten percent rule." what does this strategy mitigate?

Answer 77

increase intensity or duration less then or equal to 10% per week; mitigates overtraining

Question 78

symptoms of overtraining

Answer 78

decrease in performance, chronic fatigue, weight loss, increased infections, elevated heart rate and blood lactate levels during exercise

Question 79

how does heart rate change with overtraining in comparison to untrained

Answer 79

heart rate will be higher than their trained heart rate, but not as high as untrained heart rate

Question 80

describe the concept of tapering

Answer 80

short-term reduction in training load prior to competition which allows muscles to resynthesize glycogen and heal from training-induced damage

Question 82

define muscular endurance

Answer 82

ability to make repeated contractions against a submaximal load