1. Assessing Energy Expenditure

2. Chapter Learning Outcomes
Discuss the importance of CRF in both health and functional implications
Describe which method of testing would be appropriate in certain situations
Compare and contrast the different tests used to predict CRF
Describe the procedures to various submaximal exercise tests
Describe the threats to accurate interpretation of submaximal testing results

3. Aerobic vs Anaerobic Aerobic means “with oxygen”.
The term aerobic relates to the energy processes that occur in the presence of adequate oxygen.
“Aerobic Fitness” is the ability of the heart and lungs to provide the oxygen needs of the body (muscular system) over a sustained period of time.
Aerobic Fitness may be limited by:
O2 transport ability
Cardiac/vascular limitations
The ability of the muscles to extract and utilize oxygen

4. Aerobic vs Anaerobic Anaerobic means “without oxygen”
Short-term, intense activity due to energy system used
If continued, activity must cease due to increases in pyruvate/lactate/H2+
When oxygen availability is not sufficient to meet the demands of the workload, blood lactate concentrations start to rise significantly above resting values, triggering the AT.

5. Cardiorespiratory Fitness (CRF)
Health-related concept of fitness – the ability of the CV system to effectively deliver fuel to the exercise muscles.
Best represented by VO2MAX
Defined as the greatest rate at which oxygen can be consumed during exercise.
Typically expressed in milliliters of oxygen consumed per kilogram of body weight per minute (ml/kg/min).
EXAMPLE: Collegiate female athletes, should have a VO2MAX of 55ml/kg/min

6. Assessing VO2MAX Why? How? Aerobic, functional and work capacity
Health status
Exercise/activity prescription
How?
Maximal Graded Exercise Treadmill Test (GXT)
Laboratory assessment with direct measurement of:
O2 consumption and CO2 expiration (RER)
Blood lactate levels
12-lead EKG

7. VO2MAX Laboratory criteria for achieving a true VO2max:
Oxygen consumption plateaus during last min
RER increases to 1.15
or higher
HR within 10 bpm of
age-predicted HRmax
Blood lactate levels
rise above 8 mmol/liter

8. VO2MAX Laboratory GXT is prohibitive Estimating VO2MAX Equipment
Personnel
Safety
Estimating VO2MAX
Nomograms
Field tests for CRF
Submaximal laboratory tests
Which to use?
Equip/facilities/cost
Time
Risk to subject

9. Prediction Nomograms
Predicting VO2MAX without any exercise is possible….
VO2 = 5.0 x wt (kg)
International Physical Activity Questionnaire (IPAQ)
Regression Equations
…but poorly validated and not reliable
Use only when necessary

10. Field Tests Step tests Females: VO2 = 68.81 – (0.1847 x HR)
Harvard Two-Step Test, 1953
YMCA Step Test,
Queens College Step Test (p. 113)
Validated in 1972, r = 0.79, error + 8%
16.25in step for 3 min
Different step cadences for males/females (96/88)
Standing post exercise HR taken immediately
Threats to validity/reliability/objectivity?
Females: VO2 = – ( x HR)
Males: VO2 = – (0.42 x HR)

11. Field Tests Fixed-distance tests Fixed-time tests
6-minute walk, 1993.
1 mile walk, 1987 (p. 115). r = 0.93
1 mile run
1.5 mile run
Fixed-time tests
Beep (multi-stage fitness) test
12-min run test, 1968 (p. 115). r = 0.9
Threats to validity/reliability/objectivity?

12. Submaximal Exercise Tests
Submax tests rely on age-pred max HR
MAXHR = 220 – age
Indications for test termination based upon epidemiological data
Monitoring HR BP
EKG
Box 7.3 – General Indications for Stopping an Exercise Test in Low-Risk Adults
Onset of angina or angina like symptoms
Drop in systolic BP of >10 mm HG from baseline BP despite an increase in workload
Excessive rise in BP: systolic pressure >250 mm Hg or diastolic pressure >115 mm Hg
Shortness of breath, wheezing, leg cramps, or claudication
Signs of poor perfusion: light-headedness, confusion, ataxia, pallor, cyanosis, nausea, or cold and clammy skin
Failure of heart rate to increase with increased exercise intensity
Noticeable change in heart rhythm
Subject requests to stop
Physical or verbal manifestations of severe fatigue
Failure of the testing equipment

13. Submaximal Exercise Test
Treadmill – same test protocols (Bruce, Balke, etc…)
Cycle Ergometer tests (YMCA Submax Bike Test)
(p )
2-4 3-min stages based upon HR response to ex
50rpm pedal rate
Stopped at 85% MAXHR/ <50RPM/request to stop/emerg.
Prediction of VO2 can be graphed or calculated
Graphing requires 2+hr points
Calculation-based prediction requires “…calculating the slope of the HR and VO2 relationship….”

14. VO2 = [(1.8 x wr) / (kg)] + 7 YMCA Submax Bike Test
Graphing the results….
Pt. A – 55y, 175lb, HR1 – 120, HR
Pt. B – 30y, 215lb, HR1 – 130, HR
Pt. C – 70y, 160lb, HR1 – 95, HR
VO2 = [(1.8 x wr) / (kg)] + 7

15. Max vs Submax
Standards are norm-based (population, gender, age) for both M & SM
SEE (standard error of estimate) should be reported to the subject, if available for SM results
Objective error caused by:
Ergometer
Age-predicted maxHR
Subject’s mechanical efficiency for ergometer testing
Submax HR variability
HR/VO2 linearity **ExPhysRules
Subjective causes of testing error?