jimboalee said:It DOES NOT matter if you sit or stand, the time is the same so the overall energy ( or WORK ) is the same.
Confusion is arising because ( to some cyclists ) standing and grinding FEELS more energetic. It is if the upward velocity increases.
Given two cyclists who have the same mass; when they climb the same hill in the same time, they have done the same amount of work, irrespective of whatever riding style they have.
I do wish people wouldn't confuse the human body with a simple heat engine.That is too simplistic and it doesn't work exactly like that. Sure, whichever way you ride up a hill, you still have to have energy input (which, as I have already said, is why you need to eat - this is not a closed system either) - that is not really the issue.
However, when you are sitting and standing you are using some different muscles in some different ways. It is not a question of the overall system energy levels. More importantly still, it makes a big difference how you climb in terms of wasted motion - the human body can move in many different ways and they do not always add up to maximum possible efficiency. If you put more energy into lateral motion (moving side to side as you climb, or other unnecessary or counterproductive movement) you will either be slower or use more energy for the same distance traveled as if you keep the body as relaxed as possible except for the parts that really need to move. The fact is that the human body on a bike is a complex biomechanical system not a simple heat engine and it does make a difference which parts of the system are being placed under more or less stress or are being used more or less strenuously... the form of energy into which the initial chemical energy of food is transformed, matters immensely.