Energy of a human climbing up stairs

[lynnfauzee]

Homework Statement

According to the "internet", the efficiency of humans to climb stairs is about 25%. How much energy does a person weighing 80kg use to climb from the 4 flights (12.95m total) floor of the von Haast building?

Homework Equations

change in potential energy of a system is = mg(zfinal-zinitial)

The Attempt at a Solution

 

[Replusz]

How much times the change in potential energy does the human need, if one quarter of his work will become potential energy?
Hope this helped.

 

[Simon Bridge]

Welcome to PF;
Do you know what "efficiency" means?
Where did you get the 25% figure?

It is consistent with textbooks - at 20-30% being the usual range quoted.
That is very efficient for an engine... though you only get that by climbing fastish: about 50 or so steps per min.
(Textbook of Work Physiology: Physiological Bases of Exercise p69, 2003 by Per-Olof Åstrand et al.)