Due to the strength of the fields at many of the top marathons around the world neither of the 2012 Olympic champions ended up atop our rankings .
The world result largely from sizeable appearance fees and payouts for high placings .
Due to the strength of the fields at many of the top marathons around the world , which result largely from sizeable appearance fees and payouts for high placings , neither of the 2012 Olympic champions ended up atop our rankings .