How imperfect is the human machine

[bobie]

If we pull/ push a weight of 10kg and dislocate it 1 meter the energy spent is 10 joules, can someone tell me roughly if 10 j is 100% can anyone tell me how much energy (calories) has been burned /wasted in excess? I suppose it can vary in different persons and by different factors, I'd like to get just a rough idea, 120%?

 

[Bandersnatch]

For every Joule of work, you burn 4 to 5 Joules. Google muscle efficiency for more details.

 

[bobie]

Thanks, very helpful

 

[fedaykin]

Additionally, skeletal muscles must expend energy to maintain a force even if no work is performed as it takes energy to keep setting filaments into the contracted state. See the paragraphs under "Comparison of Smooth Muscle Contraction and Skeletal Muscle Contraction"

https://www.inkling.com/read/guyton...y-12th/chapter-8/contraction-of-smooth-muscle

 

[Vannay]

According to a book I'm reading, the human body is running roughly at 20% efficiency. Seeing that nothing can be at 100% efficiency (2nd law of thermodynamics) I'd say the human body is doing perfectly well.