1. Energy Expenditure during various Activities

2. Oxygen Uptake Energy utilized for O 2 consumed: z5 kcal/L of O 2 zIf a person burns 600 calories during a run, how many liters of O 2 did he/she consume?

3. Energy Expenditure Gross Energy Expenditure Net Energy Expenditure zexpenditure due to activity zsubtract resting energy expenditure

4. Energy Expenditure A runner burns 600 calories during a 45 minute run: z6’0” z190 lbs. zAge: 37 zFind Net Energy Expenditure

5. Energy Expenditure Runner zEstimate Body Surface Area (nomogram - Figure 9.4) zEstimate BMR (Figure 9.3) zCalculate Resting Energy Expenditure (kcal/hour)

6. Energy Expenditure Net Energy Expenditure = Gross Energy Expenditure – BMR

7. Energy Expenditure/O 2 Consumption Constant load / light to moderate exercise zAssessed 1-2x during steady state Exercise w/ varying loads zAssessed multiple times

8. Mechanical Efficiency (%) z= Mechanical work accomplished / Input of energy * 100 zMechanical work = ergometer zEnergy input = O 2 consumption zWork equivalent: 1 kcal = 426 kg-m perfect)

9. Mechanical Efficiency (%) zHuman locomotion = 20-30% zDissipated energy to internal & external friction

10. Walking Efficiency zSand  2x energy expenditure zSoft-soled running shoe   O 2 consumption x 2.4% z100g (3.52 oz.) to each shoe   O 2 consumption x 1%

11. Effects of Downhill Walking 5 6 7 8 9 10 11 12 13 14 -18-15-13-9-6-30 % Grade Net Oxygen Consumption (mL/kg-min)

12. Walking vs. Running

13. Running Economy zEnergy cost not dependent on velocity zHorizontal running  net energy expenditure = 1kcal/kg-km (1km = 0.62 miles) zA 220 lb. man runs 10 km, what is the net energy expenditure?

14. Running: Frequency vs. Stride Length Speed (km/h) 10 30 Stride Frequency and Stride Length (cm) Frequency Length 20 90

15. Walking: Frequency vs. Stride Length 120 220 Speed (km/h) 1016 Stride Frequency and Stride Length (cm) Frequency Length

16. Stride Length Stride Length (cm) 118 134 154 Oxygen Uptake (L/min) 3.3 3.5 3.7 3.9

17. Air Resistance Effect dependent on: zair density zsurface area zvelocity 2 z9.86 vs. 41 mph wind z2.92 vs. 4.1 L/min (41%)

18. Drafting zRunning @ 6 m/s z1 m behind z  energy expenditure by 7% zCycling @ 25 mph z  energy expenditure by 26-38%

19. Treadmill vs. Non-Tmill Running zNo differences aerobically (submax and max)