1. Measuring and Evaluating Energy Expenditure
McArdle, Katch, & Katch
Chapter 7

2. Overview of Energy Transfer during Exercise
Overlapping area represents generality.
For each energy system, specificity exceeds generality.
Effects of exercise training remain highly specific.

3. Overview of Energy Transfer during Exercise
At initiation of high- or low- speed movements, intramuscular phosphagens provide immediate and nonaerobic energy.
After first few seconds, glycolytic energy system provides greater proportion of total energy.
Continuation, places greater demand on aerobic pathways.

4. Measuring & Evaluating Anaerobic Energy Systems
Evaluation of Immediate Energy System
Measure changes in chemical substances used or produced
Quantify amount of external work performed during short-duration, high-intensity activity.

5. Evaluating Immediate Energy System
Power = F x D/time
Muscular short term power by sprinting up flight of steps
Jumping-power tests may not measure anaerobic power because too brief to evaluate ATP and PCr.

6. Evaluating Immediate Energy Systems
Other power tests last 6 to 8 seconds.
Low interrelationship among power tests suggests high degree of task specificity. The best sprint runner may not be the best repetitive volleyball leaper.

7. Evaluating Short-Term Glycolytic Energy System
Blood lactate level is most common indicator of short-term energy system (7.3).
Glycogen depletion in specific muscles activated provides indication of contribution of glycolysis to exercise (figure 7.4).
Tests demanding maximual work for up to 3 min. best estimate glycolytic power.

8. Evaluating Short-Term Energy System
In Katch cycle test peak power represents anaerobic power & total work accomplished reflects anaerobic capacity.
Wingate test provides peak power output, average power output, and anaerobic fatigue.
What is anaerobic fatigue?
Anaerobic fatigue: percentage decline in power relative to peak power.

9. Factors Affecting Anaerobic Performance
Specific anaerobic training
Trained have more glycogen depletion than untrained
Trained have higher levels of HLa
Buffering capacity (alkaline reserve)
Motivation

10. Measuring & Evaluating the Aerobic System
Direct Calorimetry.
Unit to measure heat is calorie. One calorie is amt. heat necessary to raise the temperature of one gram of water by 1o Celsius. Kilocalorie is generally used, 1 Kcal = 1,000 calories.
Process measuring animal’s metabolic rate via measurement of heat: direct calorimetry.

11. Direct Calorimetry Direct Calorimetry
Theory: when body uses energy to do work, heat is liberated.
Foodstuff + Oxygen  ATP + heat 
Cell work + heat
Therefore, measuring heat production (calorimetry) by animal gives a direct measurement of metabolic work.

12. Measuring & Evaluating the Aerobic System
Technique places human in airtight chamber (calorimeter) which is insulated from environment and allowance is made for exchange O2 & CO2. Body temperature raises temperature of water  computer heat production

13. Measuring & Evaluating the Aerobic System
Indirect Calorimetry
Theory. Since direct relationship between O2 consumed & amt. heat produced by body, measurement of O2 consumption provides estimate of metabolic rate.
Foodstuffs + O2  Heat + CO2 + H2O
(indirect) (direct)
Measurement of oxygen consumption is indirect, since heat not measured directly.

14. Indirect Calorimetry
Closed circuit spirometry involves rebreathing same air.
Open circuit spirometry involves breathing atmospheric air.

15. Indirect Calorimetry
Open circuit spirometry measures the volume and samples the air expired for percent of oxygen and carbon dioxide.

16. Indirect Calorimetry
Volume of oxygen consumed per minute is calculated as volume O2 inspired –volume O2 expired.
Inspired VO2 = ventilationI x .2093
Expired VO2 = ventilationE x (% O2 expired)

17. Indirect Calorimetry
Volume of carbon dioxide consumed per minute is calculated as volume CO2 expired –volume CO2 inspired.
Expired VCO2 = ventilationE x (% CO2 expired)
Inspired VCO2 = ventilationI x (.03%)

18. Caloric Transformation for Oxygen
Approximately 4.82 kcals release when blend of CHO, pro, fat burns in 1 L O2.
Physiological fuel value nutrient is amount of usable energy per gram nutrient.
Heat of combustion
% digestibility
Urinary nitrogen loss
Caloric value for oxygen varies slightly (w/i 2 – 4 %) with variation in nutrient mixture.

19. Caloric Transformation for Oxygen
Food
Energy calmeter
Energy physiologic
oxygen (kcal/L)
carbondioxide RQ
CHO
4.1
4.02
5.05 1
Pro
5.65
4.3
4.46
5.44
.82
Fat
9.45
8.98
4.68
6.63
.71
Mixed
4.82
5.89

20. Respiratory Quotient
Respiratory quotient (RQ) is ratio of volume of carbon dioxide produced to volume of oxygen consumed.
RQ for Carbohydrate is 1.0.
Glucose C6H12O6 + 6 O2  6 CO2 + 6 H2O
RQ = 6 CO2/ 6 O2 = 1

21. Respiratory Quotient RQ for fat is .70 RQ for protein is .82
C16H32O O2  16CO H2O
RQ = 16 CO2 / 23 O2 = .7
RQ for protein is .82
Protein must first be deaminated in liver.
Resulting “keto acid” fragments oxidized requiring O2 > CO2

22. Respiratory Quotient RQ for mixed diet is .82 from 40% CHO & 60% fat.
Non-protein RQ is between 0.7 and 1.0.
Thermal equivalents of oxygen for different non-protein mixtures.

23. Respiratory Exchange Ratio
Respiratory Exchange Ratio is ratio of carbon dioxide exhaled to oxygen consumed when CO2 and O2 exchange doesn’t reflect food oxidation.
RER ≠ RQ during hyperventilation and exhaustive exercise. Non-metabolic CO2.
Exhaustive exercise presents RER > 1.00.
HLa + NaHCO3  NaLa + H2CO3  CO2 + H20
Lactate Buffering by Sodium Bicarbonate.

24. Measuring Maximal Oxygen Consumption
The highest maximal oxygen uptakes generally recorded for cross-country skiers, runners, swimmers, and cyclists.
Lance Armstrong VO2 max = 83.3 ml/kg/min

25. Measuring Maximal Oxygen Consumption
Criteria for true max VO2 is leveling off or peaking in oxygen uptake.
Other criteria:
Oxygen uptake fails to increase by some value
Maximum lactic acid of mg/100 mL
Maximum predicted HR or R > 1.0

26. Measuring Maximal Oxygen Consumption
Tests of Aerobic Power
Two general criteria:
Independent of muscle strength, speed, body size, skill
Consists of graded exercise to point of exhaustion (without muscular fatigue)

27. Measuring Maximal Oxygen Consumption
Continuous versus Discontinuous
Small differences between continuous & discontinuous on bicycle, but lower than treadmill tests.

28. Measuring Maximal Oxygen Consumption
Commonly used protocols.
Vary
Exercise duration
Treadmill speed
Treadmill grade

29. Measuring Maximal Oxygen Consumption
Factors that affect Maximal Oxygen Uptake
Mode
Heredity
State of training
Gender
Body composition
Age

30. Predicting VO2 Max
Walking & Running Tests use age, gender, time for test, HR at end of test
Predictions based on HR: VO2 linearity.
Similar maximum HRs for healthy people.

31. Illustration References
McArdle, William D., Frank I. Katch, and Victor L. Katch Essentials of Exercise Physiology 2nd ed. Image Collection. Lippincott Williams & Wilkins.
Plowman, Sharon A. and Denise L. Smith Digital Image Archive for Exercise Physiology. Allyn & Bacon.
Axen, Kenneth and Kathleen Axen Illustrated Principles of Exercise Physiology. Prentice Hall.