In article ],
Chris ] writes:
The gym has machines by pulsefitness.
There seems to be a mismatch in the numbers displayed.

After a bike session the summary was:
Power average: 74 Watts.
Time taken: 9 minutes.
Energy used: 50 kcal.

The above energy figure would equate to 333 kcal per hour.
But 100 Watts is only 86 kcal per hour!

The mismatch is so enormous that I feel I must have missed something.
I would be grateful to any physicist who can shed light on the figures.

The 50kCal is an estimate of the energy you burned (input) but the
power is the power you output.

A typical figure for efficiency of the body doing this type of work
is about 20%, which gives a large difference between the input and
output values.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]