As this is a timed excersise it is often used as a competition between people - whoever can do it for the longest time wins! Anything above 3 minutes is good, 6 minutes excellent.
Tom: Me too, we must battle to the death for her heart
Joe: I too, wish to win the heart of Jayne, but death would not be adequate for her heart... We must perform... THE PLANK!!
Tom: Lets do this!