The second question is hard. If the favorite activity is doing a pull up, the energy expended is the weight times the change in elevation plus the energy to overcome the force of friction in the bodies joints and muscles, plus the energy required to increase the oxygen supply to the lungs, plus the energy required to increase the blood flow to the engaged muscles, plus probably some other stuff that I am forgetting. The only part that is easily calculated is the weight times the elevation change. If the favorite activity is running the 400 meter dash, there is essentially no net change in elevation or velocity if the track is level and the person starts and finishes the race at zero speed. That means that the sense of exhaustion one gets from that activity all comes from these other incalculable issues.
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