MELBOURNE , Australia ( AP ) -- IAAF president Sebastian Coe says he 's a big fan of the Nitro Athletics concept being showcased by Usain Bolt .
Which features mixed medley relays , sprints over non-traditional distances and elimination mile races .
MELBOURNE , Australia ( AP ) -- IAAF president Sebastian Coe says he 's a big fan of the Nitro Athletics concept being showcased by Usain Bolt and which features mixed medley relays , sprints over non-traditional distances and elimination mile races .