Chapter 7 - Energy Transfer During Physical Activity

Question 1

What is the ATP-PCr Energy System Responsible for?

Answer 1

High-Intensity Exercise of Short Duration
- Under 10 seconds

Question 2

How much ATP and PCr does each kg of skeletal muscle contain?

Answer 2

ATP
- 3-8mmol
PCr
- 12-48mmol

Question 3

What is the Short-term Glycolytic Energy System responsible for?

Answer 3

Intense, Short-duration exercise

Question 4

What results from short-term glycolytic energy systems?

Answer 4

• lactate formation

Question 5

When would there be rapid and large accumulation of blood lactate?

Answer 5

Maximal Exercise of 60-180 seconds

Question 6

What happens when you decrease intensity of exercise to extend duration?

Answer 6

• Depressed lactate accumulation rate
• Reduced final blood lactate levels

Question 7

Does blood lactate accumulate at all exercise levels?

Answer 7

• NO

Question 8

When does blood lactate not accumulate during exercise?

Answer 8

Light/Moderate Exercise
- Under 50% aerobic capacity

Question 9

Why does blood lactate not accumulate during light/moderate exercise?

Answer 9

• Lactate production equals lactate clearance
• Oxygen-consuming reactions adequately meeting exercise energy demands

Question 10

What have tracer studies that label the carbon in glucose show about lactate?

Answer 10

• 70% oxidizes
• 20% converts to glucose in muscle/liver
• 10% synthesizes amino acids

Question 11

Why would a trained person perform steady-rate aerobic exercise at 80-90% of maximum aerobic capacity?

Answer 11

• Specific Genetic Endowment
• Specific local training adaptations that favour less lactate production
• More rapid rate of lactate removal at any exercise intensity

Question 12

What is the difference between lactate concentration for trained and untrained individuals?

Answer 12

Untrained
- Early lactate threshold
- Lower max lactate tolerance
Trained
- Steep curve
- Later lactate threshold
- High tolerance

Question 13

What factors are related to the lactate threshold?

Answer 13

• Low tissue oxygen
• Reliance on Glycolysis
• Activate fast-twitch muscle fibers
• Reduced lactate removal

Question 14

What factors contribute to higher blood lactate levels during maximal exercise due to specific sprint-power anaerobic training? Are these factors permanent?

Answer 14

Factors
- Improved motivation
- Increased intramuscular glycogen stores
- Increase in Glycolytic-Related Enzymes
Permanent
- NO, reduce when training ceases

Question 15

What does lactate shuttling between cells do?

Answer 15

• enables glycogenolysis in one cell to supply other cells with fuel for oxidation

Question 16

Other than lactate production, what is the muscle also a major site for?

Answer 16

• Removal of lactate via oxidation

Question 17

What happens to glucose that is derived from lactate?

Answer 17

• Returns in blood to skeletal muscle for energy metabolism
• Synthesizes to glycogen for storage

Question 18

What is the long-term energy system?

Answer 18

• The Aerobic System

Question 19

What provides nearly all the energy transfer when intense exercise continues beyond several minutes?

Answer 19

• Aerobic Metabolism

Question 20

What happens with oxygen uptake during exercise?

Answer 20

Initially
- Rises exponentially
Eventually
- Plateaus, then remains in steady-rate for duration of effort

Question 21

Explain steady-rate aerobic metabolism

Answer 21

• balance between energy required and ATP production in aerobic reactions

Question 22

What is the relation between lactate and steady-rate conditions?

Answer 22

• No appreciable blood lactate accumulation

Question 23

What 2 factors limit steady-rate metabolism?

Answer 23

• fluid loss/electrolyte depletion
• Balance between glycogen reserves in liver for CNS and muscle to power exercise

Question 24

What two factors help explain athlete’s high steady-rate levels?

Answer 24

• High capacity for oxygen delivery to working muscles
• High capacity of active muscles to use oxygen

Question 25

Describe the oxygen deficit?

Answer 25

- the difference between total oxygen consumed and total that would be consumed with immediate steady-rate uptake

Question 26

What does the Oxygen Deficit represent?

Answer 26

- immediate anaerobic energy transfer from the hydrolysis of intramuscular high-energy phosphates and glycolysis until steady-rate energy transfer meets current energy demands

Question 27

How does the energy for exercise occur?

Answer 27

- smooth blending and considerable overlap of different modes of energy systems

Question 28

What is the oxygen uptake fast component?

Answer 28

- Exponential rise in oxygen uptake in first minutes of physical activity - plateau around 3rd or 4th minute

Question 29

What is unique about endurance-trained individuals regarding steady-rate?

Answer 29

Compared to sprint-power athletes, cardiac patients, older adults, and untrained: - Reach it more rapidly - Smaller oxygen deficit

Question 30

What causes a trained individual to consume a greater total amount of oxygen during steady-rate exercise? What else does it do?

Answer 30

Faster Aerobic Kinetic Response - makes an anaerobic component of exercise energy transfer proportionally smaller

Question 31

What three aerobic training adaptations facilitate the rate of aerobic metabolism when exercise begins?

Answer 31

- Rapid increases in muscle bioenergetics - Rapid Increase in overall blood flow - Disproportionally larger region blood flow to active muscle, complimented by cellular adaptations

Question 32

What do the three aerobic training adaptations that facilitate the rate of aerobic metabolism when exercise begins do?

Answer 32

- Increase individual total capacity to generate ATP aerobically

Question 33

What does a High VO2max require?

Answer 33

- Integrate and high-level responses of five diverse physiologic support systems

Question 34

What 5 physiologic support systems must integrate and work at high levels to get a High VO2max?

Answer 34

- Pulmonary Ventilation - Hemoglobin Concentration - Blood Volume and Cardiac Output - Peripheral Blood Flow - Aerobic Metabolism

Question 35

What four factors does Hill suggest that determine VO2max?

Answer 35

- Arterial O2 Saturation - Mixed Venous Saturation - O2 capacity of the Blood - Circulation Rate

Question 36

What quantitative estimate is made for arterial O2 saturation?

Answer 36

- Ventilation

Question 37

What quantitative estimate is made for Mixed Venous Saturation?

Answer 37

- Central Blood Flow

Question 38

What quantitative estimate is made for O2 capacity of the blood?

Answer 38

- Active Muscle Metabolism

Question 39

What quantitative estimate is made for the circulation rate?

Answer 39

- Peripheral Blood Flow

Question 40

Why are athletics used for study on exercise physiology?

Answer 40

- Simple, measurable, and constants - Athletes: reduced danger (healthy) - Exciting and new for physiology (more recruits)

Question 41

Why are both muscle twitch fibers usually required for most sports?

Answer 41

- slow, sustained muscle action - Short bursts of power

Question 42

What do athletes who excel in different sports usually have with regard to muscle fiber type?

Answer 42

- a large percentage of specific muscle fiber type that supports that sport's energy demand

Question 43

Describe Fast-Twitch Muscle Fibers

Answer 43

Type II - Rapid Contraction Speed - High Capacity for Anaerobic ATP production Type IIa - High Aerobic Capacity

Question 44

What type of movement are Type II muscle fibers good at?

Answer 44

- Change of pace - stop and go

Question 45

What type of muscle fiber is Fast-Twitch?

Answer 45

- Type II

Question 46

Describe Slow-twitch muscle fibers

Answer 46

- Generate energy through aerobic pathways - Slow contraction speed

Question 47

What type of activity are Slow-twitch muscle fibers good for?

Answer 47

- Continuous activities - Steady-rate aerobic energy transfer

Question 48

What type of muscle fiber is a slow-twitch?

Answer 48

- Type I

Question 49

What type and percentage of muscle fibers would a swim champion have?

Answer 49

Type II - Fast-twitch - 80%

Question 50

What type and percentage of muscle fibers would an endurance cyclist have?

Answer 50

Type I - Slow-twitch - 80%

Question 51

What is EPOC?

Answer 51

Excess Post-exercise Oxygen Consumption

Question 52

What 7 things contribute to EPOC?

Answer 52

- Resynthesize ATP & PCr - Resynthesize Lactate to Glycogen - Oxidize Lactate for energy metabolism - Restore Oxygen to Myoglobin and Blood - Restore thermogenic effects of elevated core temp - Thermogenic effect of hormones (catecholamines) - Restore Elevated HR, VE, other physio function

Question 53

Describe Steady-State Exercise

Answer 53

- moderate/low exercise during recovery - Facilitates recovery

Question 54

What does steady-state exercise during recovery do?

Answer 54

- Re-synthesis of high-energy phosphates - replenish O2 in blood - Replenish bodily fluids - replenish muscle myoglobin - small energy cost to elevate circulation/ventilation

Question 55

Why is passive procedure important during recovery?

Answer 55

- additional elevate total metabolism, delay recovery

Question 56

What do most individuals do when left to their own choice regarding steady-state exercise?

Answer 56

- Select optimal recovery intensity

Question 57

What does performing aerobic exercise in recovery do to lactate?

Answer 57

- Accelerates blood lactate removal

Question 58

Why does performing aerobic exercise in recovery accelerate blood lactate removal?

Answer 58

Increased - blood perfusion through the liver, heart, and ventilatory muscles - blood flow through skeletal muscles in active recovery

Question 59

Describe Intermittent Interval Physical Activity

Answer 59

- Supramaximal exercise to overload specific energy transfer system - Rapid recovery in interval

Question 60

What can you do in interval training to overload a specific energy-transfer system?

Answer 60

- Manipulate duration of exercise and rest intervals