One of the primary reasons for the length of the runways in Calgary is, of course, that the airport is almost 3,600 feet above sea level. Atmospheric conditions, density or altitude mean you are normally going to require more runway.
Whenever we do take off, we try to do what's called a balanced field takeoff. We try to use the minimum amount of thrust to depart a runway. The benefit of a longer runway is that it allows us to basically use more runway as we gain speed so that we can use less thrust for takeoff.
With regard to a shorter runway, the requirement would be to be closer to maximum thrust for departure.