A 55-kilogram woman trains on a Monark arm ergometer at 60 rpm against a resistance of 1.5 kiloponds. What is her absolute Y02?

Question

Quizplus · Accepted Answer

To calculate absolute Y02, we need to use the formula:

Absolute Y02 = (work rate)/(oxygen cost per unit of work)

The work rate can be calculated using the following formula:

Work rate = (force x distance)/time

Here, the distance moved by the arm ergometer per revolution is given as 6 meters (circumference of the wheel). So, the distance moved in one minute (at 60 rpm) is:

Distance = 6 meters/revolution x 60 revolutions/minute = 360 meters/minute

The force applied is given as 1.5 kiloponds.

So, the work rate = (1.5 kiloponds x 360 meters/minute)/60 seconds/minute = 9 kilopond-meters/second

To calculate oxygen cost per unit of work, we can use a conversion factor of 20.9 Joules/L of O2 consumed. So,

Oxygen cost per unit of work = (9 kilopond-meters/second x 1/1000 kg/kilopond x 1/20.9 Joules/L) x 1000 mL/L = 0.207 mL/kilopond-meter

Now, we can calculate the absolute Y02 as:

Absolute Y02 = (work rate)/(oxygen cost per unit of work) = (9 kilopond-meters/second)/(0.207 mL/kilopond-meter) = 43.48 L/minute

However, we need to convert this to the Y02 for the 55-kg woman. We can do this by multiplying by the woman's body weight in kilograms raised to the 0.75 power. So,

Absolute Y02 for the 55-kg woman = 43.48 L/minute x (55 kg)^0.75 = 0.840 L/minute

Therefore, the best choice is C.

A 55-Kilogram Woman Trains on a Monark Arm Ergometer at 60