Mary Keitany was runner - up last year .
Mary Keitany moved into the top spot by winning London in the year 's fastest time , 2 : 18 : 37 , and she also finished a strong fourth at the Olympics .
Mary Keitany was runner - up last year and moved into the top spot by winning London in the year 's fastest time , 2 : 18 : 37 , and she also finished a strong fourth at the Olympics .