Chapter 7

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

2. Expressing CRF Values

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 VO2max 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 VO2max • Two types • Lab tests that measure physiological responses to increasing workloads • Field tests that measure all-out endurance • Average velocity maintained gives an estimate of CRF Both types may reveal a true, measured maximal heart rate that can be used to develop target or training heart rate ranges

9. Pros and Cons of Field Testing

10. Common Field Tests • 1-mile walk test • See formula in text or use table 7.1 to estimate VO2max (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 VO2max from data obtained

12. Common Field Tests (continued) • Jog or run test • 12-minute or 1.5-mile run • Uses average velocity and O2 requirement at that velocity to estimate VO2max. 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 VO2max? 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

16. GXT: Cycle Use appropriate rpm setting: 50-60 for low to average fitness; 70-100 rpm for highly fit or competitive cyclists.

17. GXT: Treadmill

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 VO2max 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 VO2max • 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 Time of Day Time since last meal, nicotine use, caffeine use, exercise Psychological environment • Temperature and humidity • Amount of sleep before testing • Emotional state • Hydration state • Medication

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