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Chapter 11

Chapter 11. Evaluating Aerobic Fitness. Chapter 11 Outline. Essential Definitions Aerobic Fitness and Health Evaluation of Aerobic Fitness Risk Stratification for Exercise Laboratory-based Aerobic Fitness Tests Laboratory-based Maximal Tests of Aerobic Fitness

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Chapter 11

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  1. Chapter 11 Evaluating Aerobic Fitness

  2. Chapter 11 Outline • Essential Definitions • Aerobic Fitness and Health • Evaluation of Aerobic Fitness • Risk Stratification for Exercise • Laboratory-based Aerobic Fitness Tests • Laboratory-based Maximal Tests of Aerobic Fitness • Laboratory-based Submaximal Tests of Aerobic Fitness • Field Tests of Aerobic Fitness • Nonexercise Estimates of Aerobic Fitness

  3. Aerobic Fitness – ability of the heart, lungs, and blood vessels to supply oxygen to working muscles and ability of the muscles to use the available oxygen to continue work or exercise

  4. Importance of Aerobic Fitness • Related to health outcomes • Mortality risk • Cardiovascular health • Ability to meet demands of physical work

  5. Definition of Aerobic Fitness • Capacity to meet the energy demands of sustained, submaximal work • Capacity to deliver oxygen to working muscles • Capacity to extract oxygen at working muscles • VO2 max – maximal volume of oxygen one can consume during exhaustion exercise • best index of aerobic capacity

  6. VO2 max • Delivery factors: • Blood supply (cardiac output, redistribution of blood flow) • Carrying capacity (Hb, RBC) • Extraction factors: • Muscle mass • Capillary density

  7. Aerobic Exercise • Important for health promotion • Efficient exercise mode for expending calories (large muscle groups) • Examples: • Walking • Jogging • Cycling • Swimming • Group classes (Step, Spin)

  8. VO2 max • Measured during maximal exercise • Incremental test • Components: • O2, CO2, VE • Can be expressed in absolute or relative terms • Absolute – l·min-1 or ml·min-1 • Relative - ml·kg-1·min-1

  9. VO2 max – Fit vs. Less fit (Fig 11.1)

  10. VO2 max - criteria • Plateau in O2 • RER  1.15 • RPE > 17 • No increase in heart rate • Use of age-predicted maximal heart rate is discouraged

  11. VO2 max – Average vs. Athlete

  12. VO2 max Quintile Norms - Women (ACSM, Jackson et al.) (Table 11.1)

  13. VO2 max Quintile Norms - Men (ACSM, Jackson et al.) (Table 11.1)

  14. Age-adjusted VO2 max Standards* *Developed from data of Jackson et al. (1995; 1996) (Table 11.2)

  15. Risk Stratification forExercise Testing • Exercise testing carries low risk • Higher risk for maximal than submaximal testing, and for persons “at risk” • ACSM Guidelines for stratifying risk

  16. ACSM Risk Factors Positive • Family history – MI or sudden death before age 55 in father, brother, or son; before age 65 in mother, sister, or daughter • Smoking • Hypertension (SBP  140 mm Hg or DBP  90 mm Hg) • Dyslipidemia – Total (> 200 mg/dL), HDL (< 40 mg/dL), or LDL (> 130 mg/dL) • Fasting glucose – (> 100 mg/dL) • Obesity (BMI > 30 kg/m2 or waist girth > 102 cm for men and > 99 cm for women, or waist/hip ratio  0.95 for men and  0.86 for women) • Sedentary Lifestyle - (Surgeon General’s recommendations) Negative • High HDL cholesterol (HDL > 60 mg/dL)

  17. Pre-Screening - PAR-Q • Physical Activity Readiness Questionnaire • Minimum for beginning moderate exercise program • Series of Yes/No questions (see Fig 2-1 in text) • If all “No” answers, can begin exercise program or fitness testing (with caveats regarding temporary illness, pregnancy, or change in status)

  18. Laboratory-based Aerobic Fitness Tests • Treadmill protocols • Cycle ergometer protocols • Arm ergometer protocols • Maximal vs. Submaximal • Data: • gas exchange; heart rate; RPE; BP

  19. Test Selection • Match intended/existing exercise mode Treadmill: • Often yield higher maximal values • More familiar mode for most people • Running protocols may be unsuitable for some medical conditions (e.g., osteoarthritis, obese) Cycle ergometer: • Often yield lower maximal values (local muscular fatigue) • Some people may feel safer than on treadmill (balance/falling)

  20. Test Selection Arm ergometer: • Usually yields lowest maximal values (local muscular fatigue, smaller muscle mass) • Suitable for people with medical conditions affecting the legs (paraplegia, amputation, severe osteoarthritis)

  21. Cycle Protocols • Power output – cadence, resistance, flywheel distance/revolution • ACSM equations used to estimate O2 cost • Submaximal data used to estimate maximal work output or VO2 max • Based on linear heart rate/workload relationship (beyond approximately 40% VO2 max) • Different prediction models (single-stage, multi-stage)

  22. Cycle Ergometer Power Output kg.m.min-1 = kg x m.rev -1x rev.min -1 watts = kg.m.min-1 6

  23. ACSM Cycling Equation VO2 (ml.kg-1.min-1) = 1.8 ml.kg-1.m-1 x kg.m.min-1 body weight in kg) + 7 ml.kg-1.min-1

  24. Treadmill Protocols • Power output – speed, grade • ACSM equations used to estimate submaximal O2 cost (walking, running) • VO2 max can be estimated from total time in maximal test protocols (different equations for different protocols) • Balke, Bruce

  25. ACSM Walking Equation VO2 (ml.kg-1.min-1) = 0.1 (speed) + 1.8 (speed)(fractional grade) + 3.5 speed in in m.min-1 (1 mph = 26.8 m.min-1) fractional grade is treadmill grade expressed as a fraction (e.g., 8% = 0.08)

  26. ACSM Running Equation VO2 (ml.kg-1.min-1) = 0.2 (speed) + 0.9 (speed)(fractional grade) + 3.5 speed in in m.min-1 (1 mph = 26.8 m.min-1) fractional grade is treadmill grade expressed as a fraction (e.g., 8% = 0.08)

  27. Laboratory-based Maximal Tests of Aerobic Fitness • Goal is to systematically increase exercise intensity until participant reaches exhaustion. • VO2 max can be measured by open-circuit spirometry. • expired gases are measured with metabolic measurement system. • VO2 max can be estimated from maximal treadmill time. • Bruce protocol • Balke protocol

  28. The Bruce Protocol

  29. Equation to Estimate VO2 max from Bruce Protocol Maximal Treadmill Time VO2 (ml.kg-1.min-1) = 17.50 - (0.30*TT) + (0.297*TT2) - (0.0077*TT3) where TT is maximal treadmill time in minutes, TT2 is maximal treadmill time squared, TT3 is maximal treadmill time cubed.

  30. The Balke Protocol

  31. Equation to Estimate VO2 max from Balke Protocol Maximal Treadmill Time VO2 (ml.kg-1.min-1) = 14.99 + (1.44*TT) where TT is maximal treadmill time in minutes.

  32. Conversion Table to Estimate VO2 max

  33. Laboratory-based Submaximal Tests of Aerobic Fitness • Less accurate, but more practical method to estimate aerobic capacity than maximal tests.

  34. Submaximal Tests Principles • Heart rate increases in proportion to VO2 during aerobic exercise. • VO2 max is reached at maximal heart rate. • A less fit person will have a higher heart rate at any given submaximal exercise intensity than a more fit individual.

  35. HR/VO2 Relationship

  36. HR/VO2 Relationship

  37. HR/VO2 Relationship

  38. HR/VO2 Relationship

  39. SV/VO2 Relationship

  40. SV/VO2 Relationship

  41. SV/VO2 Relationship

  42. Submaximal Models to Estimate VO2 max • Single-Stage Model • Astrand-Ryhming Single-Stage Test • Multi-Stage Model

  43. Single-Stage Model VO2 (ml.kg-1.min-1) = SMVO2 * (220-age-k)  * (SMHR – K) where SMVO2 is VO2 in ml.kg-1.min-1 at the submaximal exercise intensity, 220-age is the estimate of maximal heart rate, SMHR is the submaximal heart rate at SMVO2, and k is a constant of 63 for men and 73 for women.

  44. Submaximal VO2 • When using Submaximal Models, submaximal VO2 (SMVO2) is estimated from ACSM cycling, walking, or running models.

  45. Astrand-Ryhming Single-Stage Test • Can be administered on a cycle ergometer, treadmill, or step. • Cycle protocol last 6 minutes. • Pedal rate is 50 rpm. • Heart rates between 125 and 170 bpm are used for prediction.

  46. Multi-Stage Model • Heart rate and power output must be measured at two or more submaximal levels. • YMCA is best known multi-stage test. • Heart rates between 100 and 150 bpm are used. • 3-minute exercise stages are used. • VO2 max is estimated by plotting heart rate – power output relationship.

  47. Estimating Maximal Workload - for a 40-yr-old client If client weighs 50 kg: 2.0 L/min = 40 ml/kg/min; 2.2 L/min = 44 ml/kg/min; 2.4 L/min = 48 ml/kg/min;

  48. YMCA Protocol 1st Power Output 150 kp.m.min-1 3 Minute Stages HR 80-89 HR 90-100 HR <80 HR >100 2nd Power Output 750 kp.m.min-1 600 kp.m.min-1 450 kp.m.min-1 300 kp.m.min-1 3rd Power Output 900 kp.m.min-1 750 kp.m.min-1 600 kp.m.min-1 450 kp.m.min-1 4th Power Output 1050 kp.m.min-1 900 kp.m.min-1 750 kp.m.min-1 600 kp.m.min-1

  49. Multi-Stage Model VO2 (ml.kg-1.min-1) = VO2.2 + b(220 – age - HR2) b = (VO2.2 - VO2.1)  (HR2 – HR1) where VO2.1 is VO2 at stage I, VO2.2 is VO2 at stage II, HR1 is heart rate at stage I and HR2 is heart rate at stage II.

  50. Submaximal Treadmill Models • Both single-stage and double-stage models can be used to estimate VO2 max from treadmill tests.

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