1. Chapter 7 7 Assessment of Cardiorespiratory Fitness C H A P T E R Edward T. Howley

2. Expressing CRF Values Unit of measureInterpretation L  min -1 Liters of O 2 used by the body each minute ml  kg  min -1 Milliliters of O 2 used by each kilogram of body weight each minute METs Multiples of resting metabolic rate (1 MET = 3.5 ml  kg  min -1 )

3. How Is CRF Testing Useful? Provide a base for exercise programming Evaluate positive or negative changes in fitness over time Evaluate the effectiveness of current training program Determine physiological responses at rest and with exercise Screen for coronary heart disease (CHD) Determine ability to perform specific work tasks

4. Factors to Consider When Choosing CRF Testing Age Fitness level Current health status Risk of CHD Financial cost (supervision of physician versus fitness professional)

5. Sequence of Testing Informed consent Health history (assigning risk category) Screening Is physician consent needed before maximal testing? Submaximal testing? Review history for absolute and relative contraindications Complete resting CV tests (BP, HR, ECG) and body composition (continued)

6. Sequence of Testing (continued) Submaximal CRF testing Estimate VO 2 max via extrapolation Complete tests for low back function Begin moderate-intensity activity (for previously sedentary people) Test for muscular strength and endurance Bring back client for maximal CRF testing

7. Sequence of Testing (continued) Revise activity program as needed (including games and sports) Schedule period retests to determine effectiveness of program

8. Maximal CRF Testing to Measure or Estimate VO 2 max

9. Pros and Cons of Field Testing ProsCons Moderate to high correlation of VO 2 max Difficult to monitor physiological changes Use of natural activitiesEnvironment can affect outcome Ability to test in groupsLack of submaximal testing protocols

10. Common Field Tests 1-mile walk test See formula in text or use table 7.1 to estimate VO 2 max (data in table should be adjusted for proper weight) Use percentile rankings in table 7.2 to establish current level (goal should be at least “good” ranking) (continued)

11. Common Field Tests (continued) PACER (Progressive Aerobic Cardiovascular Endurance Run) 20-meter progressive shuttle run Beginning pace of 5.3 mph and increasing 0.3 mph at each level Formulas exist for estimating VO 2 max from data obtained

12. Common Field Tests (continued) Jog or run test 12-minute or 1.5-mile run Uses average velocity and O 2 requirement at that velocity to estimate VO 2 max. Use formula from chapter 6. Optimal run time is somewhere between 10 and 15 minutes. Why? Will this formula overestimate or underestimate a child’s VO 2 max? A competitive runner? One who is allowed to walk during the test? Explain.

13. Common Field Tests (continued) Canadian Aerobic Fitness Test Submaximal rather than maximal 3-minute stages of stepping Stages in test are determined by HR response to previous stage Classifies subjects’ CRF results as undesirable, minimum, and recommended See text for scoring information

14. Graded Exercise Tests (GXT) Subject progresses through an incrementally increased workload Endpoint is maximal (client stops because of exhaustion), submaximal (client reaches 85% of maximal heart rate), or symptom limited (client stops due to discomfort or abnormal physiological responses). When might a maximal test be indicated? When might a submaximal test be indicated? Explain.

15. GXT: Step ProsCons Low-cost equipmentUnnatural movement for many people PortabilityDifficult to take measurements (BP) Minimal number of stages for any given step height Pacing may be difficult to regulate

16. GXT: Cycle ProsCons HR and BP measurements relatively easy to take Leg fatigue may force a client to stop before VO 2 max Safe for those with balance problems Pacing may be difficult to regulate Lack of portability Use appropriate rpm setting: 50-60 for low to average fitness; 70-100 rpm for highly fit or competitive cyclists.

17. GXT: Treadmill ProsCons Natural activityClients often want to use handrail. How does this affect VO 2 estimation? Why? Reproducible because the treadmill maintains the speed Lack of portability Expense of equipment

18. Common Variables Measured During GXTs Heart rate (HR) Fitness indicator at rest and at submaximal levels Obtaining true maximal HR can improve accuracy of training heart rate Take for 30 seconds at rest or during steady-state activity; convert to 1-minute reading Take for 10 to 15 seconds postexercise. Why not longer? (continued)

19. Common Variables Measured During GXTs (continued) Blood pressure (BP) Systolic blood pressure should rise with increasing workloads Diastolic blood pressure remains the same or may decrease slightly Proper cuff size is imperative for accurate readings Rating of perceived exertion (RPE) Gives subjective information regarding intensity of activity

20. Estimating Functional Capacity From a GXT Functional capacity indicates the highest rate of oxygen utilization during which HR, BP, and ECG responses are considered normal. Is functional capacity always reflective of maximal capacity? Explain. Choosing the correct stage length to accurately determine functional capacity How is the estimation affected when the incremental increases are too large for the subject? Too small?

21. Predicting VO 2 max From Submaximal Test Data Based on the linear response of HR between 110 bpm and 85% of HRmax SEE = 5 ml  kg -1  min -1 Very reliable for tracking progress over time, regardless of accuracy of estimated VO 2 max Because estimation is based on submaximal HR responses, conditions that affect HR should be noted

22. Factors That Affect Submaximal Heart Rate Response to a GXT Temperature and humidity Amount of sleep before testing Emotional state Hydration state Medication Time of Day Time since last meal, nicotine use, caffeine use, exercise Psychological environment

23. Figure 7.3

24. Figure 7.4

25. Figure 7.6

26. General Indications for Stopping Exercise Testing (low-risk adults, nondiagnostic) Onset of angina Drop in SBP or >10 mmHg from baseline or failure to rise with increasing workload Excessive rise in SBP (>250 mmHg or DBP of >115 mmHg) Shortness of breath, wheezing, leg cramps, claudication Signs of poor perfusion, light-headedness, confusion, ataxia, pallor, cyanosis, cold or clammy skin Noticeable change in heart rhythm Subject requests to stop Physical or verbal suggestion of severe fatigue Failure of testing equipment