Question

Only use ACSM Equations / Metabolic Calculations and Conversions

How long does a 62-kg woman need to ride a Monark cycle ergometer in order to expend 500 kcal during her workout? The resistance is set at 2.0 kg and her self-selected pedaling rate is 90 rpm.

Answer 1

The power of the instrument in leg ergometry is given by

Power = kg setting * D * pedaling peed in rpm

Here, the Kg setting = 2 kg

For monark cycle, D = 6 m

rpm = 90

So,

Power = 2*6*90 = 1080 kg m/min

Power in watts = 1080/6 = 180 W

For leg ergometry,

VO2 is given by

VO2 = 1.8*work rate/body mass + 7

Here, body mass = 62 kg

So,

VO2 = 1.8*180/62 + 7 = 12.2258 ml per kilogram per minute = 12.2258*62/1000 = 0.75799 L/min

The caloric expenditure per minute is C = 5*VO2 = 5*0.75799 = 3.7899 kcal/min

So, to expend 500 k cal, she must work for

t = 500/3.7899 = 131.929 minutes.