Originally Posted by urbanknight
I think the only reason heavier people descend more quickly is that theis weight can be shifted around more readily without sacrificing stability.
Shifting the weight around has absolutely no effect on descent speed, except if it makes you more or less aerodynamic. A heavier person is almost certainly going to have a larger silhouette, and thus more air resistance, than a light person. Yet, the heavier person descends faster than a light person because the difference in air resistance is almost always less than the difference in weight.