Against which force we do work while walking?

Walking makes us tired, which implies that we must loose energy against some force. But what is that force? That force can not be friction as the friction acting is static friction and while friction is acting there is no displacement so work done by friction is 0. The answer to this question is very interesting.

You must have observed that while walking your leg goes up and then down. If u take longer steps then you can also observe the height of your body decreasing. So to lift your body up you need to do work against gravity and that’s where your energy goes . But then gravity is also doing +ve work on us when leg is going down so won’t we gain energy. No as that energy will not be stored as biological energy.

So gravity is the force which makes us tired while walking !!

THANKS FOR READING 

                -Arvin Gupta