I have looked this up on the net, but Can not make much sense of it on the cites I have looked at.
I gave it to a personal trainer, and he has not given me the answer.
thanks,
jesse
What sort of sadist wants you to do this conversion? Foot-pounds are lousy units for energy, since they are easily confused with foot-pounds of torque (which just ain’t the same thing).
Anyhow, I found a conversion chart that says that 1.356 foot-pounds is one joule. It also says that 4.1868 calories is one joule. That would mean that 3.0876 calories is a foot-pound.
Of course, you’re probably talking about nutritional Calories (note the capital C), which are actually kilocalories. That would mean that a foot-pound is actually only 0.0030876 Calories.
So, 100 kilocalories should be about 25,800 foot-pounds.
Disclaimer: Someone will appear in the next day or so and show an error in my figures, or maybe it will turn out that I read the conversion factors wrong, or the site I got them from is incorrect. Whatever, but don’t trust what I posted without checking it over.
I got about 308,892 foot pounds, or somewhere around 30 minutes of exercise for an average person. This is using the multiplier of 3088 to convert kilocalories to foot pounds.
One horsepower (1,980,000 f/p of work per hour) = 641 calories. Divided, you’ll get 3088. Multiply that by 100. Since I don’t know of many people who can maintain that pace (burning 100 calories in about 9 minutes), it’s more reasonable to assume a rate of 200-300 calories burned per hour during exercise.
http://www.seecousa.com/conversions3.htm
Consider me covered by Saltire’s disclaimer though, and check the figures yourself. Especially when it’s after midnight for me and I’m tired. 
1 Kg*m = 41 cal = 9.804 jul
1 Calorie (nutritional calorie) = 1 kcal = 1000 cal
1 cal = 4.184 J
1 J = 0.737562 ft-lb
Therefore:
1 kcal = 3086 ft-lb
100 kcal = 3.086 x 10[sup]5[/sup] ft-lb
Dire Wolf has the correct answer, then. Saltire apparently reversed some of his conversion factors, as did Sailor.
However, Dire Wolf, a horsepower (550 ft-lb/s) is a unit of power (go figure), which is energy per time. You are apparently referring to a horsepower-hour, which is equivalent to 641.6 kcal.
I just copied and pasted that line from a file I have where I keep that kind of stuff. I was talking on the phone and could not write more, just wanted to contribute that.
Yes, two different magnitudes, work and torque, can be expressed in units of force X distance. I see no cause for confusion though and this is a convenient way to express work if that is the kind of work you are dealing with.
Regarding the conversion rate of the human body and other animals, it is quite bad as most of the energy is just dissipated in the form of heat. Every calory you burn does not go to useful work. There was a ythread about this not too long ago with some cites and figures.
I don’t have the charts handy and I’m not going to look it up, but it’s very easy to burn at least twice that much. Jogging, for example, at an easy pace burns 600 Calories an hour. Swimming and biking are similar. So “I don’t know any one who can burn 100 Calories in about 9 minutes” means that you don’t know any one who exercises. If you run at a good pace, you can burn 800-1000 Calories an hour.
A calorie (small “c”) is the amount of energy needed to raise one cc of water 1 degree Centigrade, IIRC. As Sailor noted, most of the calories are consumed in heat: keeping the body’s heat stable at around 98 degrees.
Ah-ha! I was correct! Unfortunately, the correct part was mostly in the disclaimer.
I really should stop answering these things without a good reference book in hand.