High School

Lynn Aaron is cranking a Monark arm ergometer at 50 rpm with a resistance of 2.5 kg. This is her maximum workload. Her current body weight is 126 lb. Calculate the following:

a. Relative \(\dot{VO}_2\) in mL/kg/min

b. Absolute \(\dot{VO}_2\) in L/min

Answer :

a. Relative VOâ‚‚Ë™ = 13.10 ml/kg/min

b. Absolute VOâ‚‚Ë™ = 0.75 L/min

a. Relative [tex]\( \text{VO}_{2}\dot{} \)[/tex] in ml/kg/min:

1. Convert Lynn's body weight from pounds to kilograms:

[tex]\[126 \text{ lb} \times \frac{1 \text{ kg}}{2.205 \text{ lb}} = 57.15 \text{ kg}\][/tex]

2. Use the formula for relative [tex]\( \text{VO}_{2}\dot{} \):[/tex]

[tex]\[ \text{Relative VO}_{2}\dot{} = \frac{\text{Resistance} \times \text{Crank rate} \times 6}{\text{Body weight}}\][/tex]

3. Substitute the given values into the formula:

[tex]\[ \text{Relative VO}_{2}\dot{} = \frac{2.5 \text{ kg} \times 50 \text{ rpm} \times 6}{57.15 \text{ kg}}\][/tex]

4. Perform the calculation:

[tex]\[ \text{Relative VO}_{2}\dot{} = \frac{750 \text{ kgâ‹…rpm}}{57.15 \text{ kg}}\][/tex]

[tex]\[ \text{Relative VO}_{2}\dot{} \approx 13.10 \text{ ml/kg/min}\][/tex]

b. Absolute [tex]\( \text{VO}_{2}\dot{} \)[/tex] in L/min:

1. Convert the relative [tex]\( \text{VO}_{2}\dot{} \)[/tex] from ml/kg/min to L/min by multiplying by Lynn's body weight in kg:

[tex]\[13.10 \text{ ml/kg/min} \times 57.15 \text{ kg} = 748.65 \text{ ml/min}\][/tex]

2. Convert the result from ml/min to L/min by dividing by 1000:

[tex]\[748.65 \text{ ml/min} ÷ 1000 = 0.74865 \text{ L/min}\][/tex]

So, Lynn's absolute [tex]\( \text{VO}_{2}\dot{} \)[/tex] is approximately 0.75 L/min.