Cooper Lutkenhaus was eliminated in his 800m heat at the World Athletics Championships in Tokyo

Cooper Lutkenhaus was eliminated in his 800m heat at the World Athletics Championships in Tokyo

American 16-year-old Cooper Lutkenhaus vowed to come back stronger after being eliminated in the 800 metre heats at the World Athletics Championships on Tuesday, comparing it to "failing a math test".

The Texas high-school student became the youngest runner to represent the United States at a world championships but made an early exit after finishing seventh in his heat in Tokyo.

Originally published on doc.afp.com, part of the BLOX Digital Content Exchange.