How many joules expended for a push up?

by wannab
Tags: energy, press up, pressup, push up, pushup
wannab is offline
May18-13, 09:53 AM
P: 32
Just wondering if any of you can do the calculation that well approximates the amount of joules expended by a push up.
Phys.Org News Partner Physics news on
The hemihelix: Scientists discover a new shape using rubber bands (w/ video)
Mapping the road to quantum gravity
Chameleon crystals could enable active camouflage (w/ video)
256bits is offline
May18-13, 10:15 AM
P: 1,271
Sure. Determine the centre of mass of the body ( which might be around your belly button or a bit higher ) and then calculate the amount of work needed to raise the centre of mass by doing a pushup. By the way, this will be lower than the energy the body is using internally. Other muscles, for example the stomach muscles, are contracting to keep the body straight.
wannab is offline
May20-13, 06:01 PM
P: 32
I'm around 80kg and I go about 0.5m high. So the change in potential energy is 80*9.8*0.5 = 392 J

Is that a reasonable estimate of the total minimum possible expended energy?

Can you believe a few years ago I was on the second year of an undergraduate Physics degree!? It has completely fallen out of my head -_-

wannab is offline
May20-13, 06:03 PM
P: 32

How many joules expended for a push up?

That would mean a few hundred pushups would be expending the same energy as a half-marathon (according to a running app of mine) ... that can't be true

maybe i'm confusing calories with kcal or something. hmmfph.
Redbelly98 is offline
May20-13, 06:28 PM
Redbelly98's Avatar
P: 11,989
Quote Quote by wannab View Post
maybe i'm confusing calories with kcal or something. hmmfph.
That's probably it. You're calculation of 400 J looks reasonable.

Keep in mind that a joule is a pretty miniscule amount of energy. There is a reason electric companies charge by the kW-hr (millions of joules), rather than by the joule.
mfb is offline
May20-13, 06:31 PM
P: 10,853
I think 0.5m is a bit on the high side.
There is a large difference between the raw power output (here: used to lift the body) and the amount of chemical energy the body needs. I don't know how the running app calculates its values.
antlhem is offline
Jul17-13, 05:13 PM
P: 1
Hi guys, i came up with this relations between food and physical exercise,here my calculations:
Weight=70kg, Distance for push up=0.5m, Distance for squad=0.5m, distance for abs=0.5m.
70kg(9.81m/s2)=686.7N, so in exercise minimum i have to move my center of mass 0.5m:
1 push up=1squad=1abs: 343.35J=82.06cal
Lets say that i eat one can of tuna fish=94.9kcal
To waste the energy from tuna fish i would have to do 385 push ups, squads and abs!!!
hahahaha to much!!!
Be aware that these are very simple calculations
mfb is offline
Jul17-13, 06:13 PM
P: 10,853
Your body is not 100% efficient, so this number gets reduced significantly. In addition, you need energy even if you are resting (of the order of 100W thermal, ~2000kcal/day, but with significant variation in the population).

Register to reply

Related Discussions
Work expended moving a charge Introductory Physics Homework 5
Expended Fermats last theorem Linear & Abstract Algebra 6
Calculating expended energy in a battery Introductory Physics Homework 2
energy expended, no work done? Classical Physics 6
energy expended General Physics 0