Lanky like me? Don't be ashamed of your push-up count.
If we generalize and say that my longer legs cause my center of gravity to be 1.25x further away from my feet, and that I weigh 1.25x his weight, we can plug mass and center of gravity length (as r) into
Thus, there is 1.6x as much torque acting on me due to gravity than my friend. In order to counteract that gravity and hold myself up above the ground, I must apply a force while pushing up of at least
1.6=(77 inches/69 inches)FsinΘ
1.43x as much as my friend. And this doesn't even begin to take into account the length of my arm, which means that I would have to apply a larger force over a longer distance, requiring more energy. I'll be showing him these numbers next time we do push-ups.
By Chris Wetzel