FILE - In this Aug. 17, 2013, file photo, Jamaica's Usain Bolt competes to win the men's 200-meter final at the World Athletics Championships, in Moscow, Russia. The man who reshaped the record book and saved his sport along the way is saying goodbye. His runs through the 100 meters and Jamaica's 4x100 relay at next week's world championships are expected to produce golds yet again, along with leaving people to wonder who could possibly take his place. (AP Photo/Alexander Zemlianichenko, File)