Originally Posted by Hslater
A 68x11 gear at that speed is only a cadence of 53 rpm. There must be some kind of crazy amount of force being put into those pedals. I wonder what weight of leg press would even be comparable - whatever it is I bet I couldn't do 3,180 reps.
By a very rough calculation... If they are 205mm cranks, and assuming a power output of ~400W with 100% mechanical efficiency, the AVERAGE force that would need to be applied to the pedals (assuming one being pressed at a time) would be ~600N which equates to 60kg.
That's equivalent therefore two a two-legged leg press of 120kg, once a second, for an hour! Good effort!