Originally Posted by
sreten
How hard you are trying makes no difference to the calories burned.
That's almost certainly not true. First, not all energy is going into movement. If somebody feels like they are working harder, they are probably using more calories with non-propulsion muscles (such as heart and lungs) which would mean they're burning more calories.
Originally Posted by
sreten
There is no mechanism to become more efficient at burning calories.
The chemistry and conversion in a muscle fibre doesn't change.
That isn't obvious to me either. From some
random post on the internet:
Muscle cells build more mitochondria in response to the demands placed upon them by exercise. Cells themselves become more efficient. The type of muscle used during exercise will drive which cells develop.
I'm not claiming this is right (at all), but it is consistent with my understanding: that the human body does become more efficient for a given activity when practiced. I wasn't able to find a convincing answer one way or the other Googling around (and this is not my field of expertise at all).