Lecture 3 (Exam 2)

Question 1

Direct Calorimetry

Answer 1

Measures the body’s heat production to calculate energy expenditure & ~60% of energy produced is released as heat
-Expensive process and cannot follow rapid changes in energy release

Question 2

Indirect Calorimetry

Answer 2

Estimates total body energy expenditure based on RER of VO2 used, VCO2 produced

• Heat production is not measured here
• Only accurate for steady-state oxidative metabolism

Question 3

Maximal Oxygen Uptake (VO2max)

Answer 3

Point at which O2 consumption doesn’t increase with further increase in intensity

• Best single measurement of aerobic fitness
• Not best predictor of endurance performance
• Plateaus after 8 to 12 weeks of training
• More training allows athlete to compete at higher percentage of VO2max

Question 4

Basal Metabolic Rate (BMR)

Answer 4

Measurement takes place while the subject rests, no food within the past 12 hours, no physical activity within 2 hr
-the lowest amount of energy needed to maintain normal regulatory balance (about 1200 – 2400 kcal per 24hr)

Question 5

Resting Metabolic Rate (RMR)

Answer 5

RMR = 60 – 75% of total daily energy expenditure

Question 6

Steady State

Answer 6

Refers to the energy cost (VO2) at a specific power output

Question 7

Peak Oxygen Uptake (VO2peak)

Answer 7

point of volitional fatigue before VO2max is “truly” reached

Question 8

Absolute VO2max

Answer 8

expressed in an absolute value of LO2/min

-Untrained young men: 44 to 50 versus Untrained young women: 38 to 42

Question 9

Relative VO2max

Answer 9

expressed in a relative value (i.e., body weight) of ml O2 kg-1/min-1

• allows for a more accurate comparison of VO2max for different-sized individuals
• Untrained young men: 44 to 50 versus Untrained young women: 38 to 42

Question 10

Excess Postexercise Oxygen Consumption (EPOC)

Answer 10

Volume of O2 consumed during the minutes immediately after exercise ceases that is above that normally consumed at rest
-O2 consumed > O2 demanded amount in early recovery

Question 11

Oxygen Deficit

Answer 11

O2 needs and O2 supply differ from transition of rest to exercise
-O2 demand > O2 consumed in early exercise OR O2 required − O2 consumed
Occurs when anaerobic pathways used for ATP production

Question 12

Lactate Threshold

Answer 12

point at which blood lactate accumulation increases significantly
-Lactate production rate > lactate clearance rate
-Interaction of aerobic and anaerobic systems
-Good indicator of potential for endurance exercise
Resting lactate levels are ~ 0.8-1.5 mmol/L

Question 13

Lactate and Performance

Answer 13

expressed as a percentage of VO2max is one of the best determinants of endurance performance

• Untrained people: LT of 50 – 60 % of VO2max
• Trained: LT 70 – 80 % of VO2max

Question 14

Respiratory Exchange Ratio (RER)

Answer 14

The ratio between CO2 released (VCO2) and oxygen consumed (VO2)
-can be used to determine energy substrate used at rest and during exercise with a value of 1.00 indicating CHO and 0.70 indicating fat
-Each liter of oxygen consumed generates ~ 5 kcal of energy
-Predicts substrate use, kilocalories / O2 efficiency
Equation RER = VCO2/VO2

Question 15

3 components of Total Daily Energy Expenditure (TDEE) and their % contributions to TDEE

Answer 15

Physical Activity - 15-30%
Thermogenesis effect from eating - 10%
RMR - 60-75%

Question 16

5 Factors Affecting Basal Metabolic Rate (BMR)

Answer 16

Mass: The more fat free mass the ↑ BMR
Body Surface: ↑ body surface area for more heat loss ↑ BMR
Age: BMR ↓ with ↑ age, generally due to loss of FFM
Stress: ↑ stress ↑ activity of SNS which ↑ BMR
Temperature: BMR ↑ with ↑ temperature

Question 17

4 Factor Effecting Daily Energy Expenditure (DEE)

Answer 17

Physical Activity
Diet-Induced Thermogenesis (from eating)
Climate
Pregnancy

Question 18

Normal Values of BMR

Answer 18

1200 - 2400 kcal/24hr

Question 19

5 Causes of Fatigue

Answer 19

Phosphocreatine depletion
Glycogen depletion
-"hitting a wall" during a 400m
Lactic acid accumulates during brief, high-intensity exercise
Neuromuscular Fatigue
Stress and psychological factors

Question 20

4 Criteria for VOmax Attainment

Answer 20

Demonstration of leveling off in VO2
Attainment of age-predicted max heart rate
RER > 1.10
RPE > 17

Question 21

Factors Responsible for EPOC

Answer 21

• Rebuilding depleted ATP stores
• Clearing lactate produced by anaerobic metabolism
• Replenishing O2 supplies borrowed from hemoglobin and myoglobin
• Removing CO2 accumulated in body tissues
• Reduce body temperature
• Remove circulating hormones due to increased respiratory rate

Question 22

Norms for VO2max

Answer 22

Untrained young men: 44 to 50 versus untrained young women: 38 to 42

• TM exercise usually produces highest values with arm crank exercise about 70% of TM
• Swimmers achieve VO2max values about 11% below TM during swimming tests

Question 23

4 Factors of having Endurance Success

Answer 23

1. High V•O2max
2. High lactate threshold (as % V•O2max)
3. High economy of effort
4. High percentage of type I muscle fibers

Question 24

3 Adaptations in Aerobic Training

Answer 24

• Improved sub-maximal aerobic endurance and VO2max
• Muscular changes in fiber size, blood and oxygen supply
• Changes depend upon genetic factors with upper limits

Question 25

Aerobic Training

Answer 25

leads to:

• improved blood flow
• Increased capacity of muscle fibers to generate ATP

Question 26

Muscular Adaptations of Aerobic Training

Answer 26

• Increased size of ST fibers but no change in fiber type. Within fiber type FTx become more FTa (more oxidative)
• Increased number of capillaries supplying the muscles
• Increased myoglobin content of muscle by 75% to 80%
• Increased number, size, and oxidative enzyme activity of mitochondria