Jonathan Commentor wrote:
def not. grade is far more important. US highschool seasons are built around yearly training cycles, prepping for xc and track. Someone who is born in july of 2005 is currently a junior, someone born in september of 2005 is currently a sophomore. the junior will have had 6 cycles of prepping for xc and track, the sophomore 4. The junior will have a huge advantage despite being only slightly older. That is why the US has such an emphasis on grade over age. unless there is an obvious advantage/disadvantage, such as if someone graduates HS when they're 19 or 17.
Athletics is one of the most global sports of all. Running in particular is accessible to most people so makes even more sense to judge across the same global standards which is age as opposed to school year when this changes over at different points in the calendar in different countries and continents.
Same principle as the mile being run in no major championships and only a handful of notable meets per year yet discussion about High School mile times seems to dominate the thoughts of many posters. Maybe US runners would punch their weight globally at middle distance if they consistently raced the 1500 at their development stages.