Calculating Calories Burned Whilst Lifting?

[broken_legs]

Soooooooooo

Physics 9 was a LONG time ago for me. I'm trying to figure out how much work/calories I am burning while lifting weights. I know it depends on body mass, metabolism, intensity and all that jazz, but I think I should be able to tell the bare minimum based on the physical WORK I have accomplished, no?



For Example:

One Repetition of a Power Clean:
D = 1.5 m
M = 62 kg
A = Gravity 9.8 m/s2 (not accounting for speed of lift???)

So I remember that
Force = Mass * Acceleration

And
Work = Force*Distance

Soooooo
F = (62kg * 9.8m/s^2)
F = 607 N

(i believe this to be the normal force that holds the weight in equilibrium on the rack, if Im lifting it, im actually applying more force - But for now we'll stick with that to keep it simple)

W = (607 N) * (1.5 m)
Work = 910 NM or 910 Joules

Now the conversion from Joules to Calories is 4.18 so
910 joules/(4.18 joules/calorie) = 217 Calories

So every time I do one power clean I am burning 217 calories???? This cannot be!

Can someone tell me what im doing wrong here?

[liquidboi69]

Physics does not work on muscles. I have tried to build a calculator on excel for this, and came up on an article written by a person with a PHD.

He basically said that muscles burn more calories when the weight is closer to 100% of your 1RM (more intensity = more cals burned.)

An example of this is that a 100lb girl could squat the same amount of weight as a 300lb guy. They are both doing the same amount of work in a physics sense (assuming the distance is constant.)

However, we all know that in real life, the girl is putting in more effort, and burning more calories.

Even if this formula worked on muscles, you did the formula wrong. Food is measured in KCals, which we abbreviate as cals. So a power clean burns "0.217" food cals. But factoring in the intensity...no one knows how much it burns.

I actually did the same mistake initially in my calculations so don't feel too bad. I scraped the excel file all together now however..due to the inherent inaccuracy of these calculations.

EDIT: I just noticed you said that not factoring in intensity...metabolism...etc. But I still don't think calculating a bare minimum is even close to accurate. You might as well take a shot in the dark at the amount you burned based on perceived rate of exertion because there are so many factors...intensity...bar path (it is not perfectly vertical even if you try,) rest periods, etc.

[broken_legs]

^^ Thanks for the reply. I totally missed the kcals!


I was really hoping i'd come up with some number like 10 calories for each power clean, so if I did 10, that would be 100 cals


ahhhhhh well

[wintonyk]

Originally posted by broken_legs
^^ Thanks for the reply. I totally missed the kcals!


I was really hoping i'd come up with some number like 10 calories for each power clean, so if I did 10, that would be 100 cals


ahhhhhh well

if that were the case, some days I would burn in excess of 2000 calories in a matter of 20 minutes.

Lifting will never burn as much calories during a workout as cardio. However, you will bring metabolism up as your muscle mass increase.