When I am standing and cranking up a steep rise my weight is not constant. Try bouncing up and pushing down on a foot scale. I am pushing down on the pedal with the momentum of my falling 225 pounds plus all the push I can muster. This must be a whopping amount because it becomes very difficult very quickly. I then morph into an air machine to try not to die before reaching the top. Now I’m on a single speed so my cadence can’t drop below a certain level or my pedals will break. Or crank. Or chain. Or B.B. done it all...a high cadence seems to get those pedals over the arc.