Playing the pedals poses another major challenge--stability and balance. To achieve these, a pianist uses the seat and both feet in a sort of tripod-like fashion.
The organist cannot use the feet for stability and balance because they must remain available for pedal playing. He is actually suspended from a single area--the seat and the base of the legs. It is through this relatively small area that stability and balance for the entire upper body and the legs must be achieved.
Since the organist achieves stability mainly through balance, all elements of bench and “person” placement are essential to good organ playing.