if you use the method of yarding on the wheel with the chain wrapped you get two advantages over standing on the pedals.

Your gearing is setup for speed not torque so the advantage is actually to the cog not to your lever arm (crank arms). if you are pulling on a 700C wheel then you have a leaver arm of about 8 to 1 over the cog.

In addition there is no "flex" in the above method, whereas when you stand on the pedals there is "flex" in the movement of the bike and other factors.

Milo