KOPS - Knee Over Pedal Spindle

Rider pedals for a while, then stops with crank at horizontal. Plumb dropped from tibial tubercle of leading knee should (ideally) intersect the crank at the pedal spindle or slightly posterior to the spindle.

This theoretically prevents the knee from experiencing undue shear forces during the peak application of force to the crank.

KOPS can be adjusted by either raising or lowering the saddle, or sliding the saddle posteriorly or anteriorly... and figuring out how much of each is needed is where the preferred muscle length info becomes very important!

Top tube length of an existing bike isn't really an issue when figuring KOPS, as the cranks are immutable and you must fit from cranks to saddle, and only last to bars. Messing with saddle position only to change relationship to the bars is a big no-no. (cuz then you throw off the relationship to the cranks, which can't be moved)