Jamaica's men's 4x100m relay gold medalists from left, Nesta Carter, Asafa Powell, Nickel Ashmeade and Usain Bolt celebrate on the podium at the World Athletics Championships at the Bird's Nest stadium in Beijing, Sunday, Aug. 30, 2015 (AP)

Jamaica's Usain Bolt, right, anchors the Jamaican team to the finish line as Jamaica wins the men's 4x100m relay final at the World Athletics Championships at the Bird's Nest stadium in Beijing, Saturday, Aug. 29, 2015 (AP)

Jamaica's Usain Bolt crosses the finish line as Jamaica wins the men's 4x100m relay final at the World Athletics Championships at the Bird's Nest stadium in Beijing, Saturday, Aug. 29, 2015 (AP)

Jamaica's Usain Bolt crosses the finish line as Jamaica wins the men’s 4x100m relay final at the World Athletics Championships at the Bird's Nest stadium in Beijing, Saturday, Aug. 29, 2015 (AP)

Jamaica's Usain Bolt competes in the men’s 4x100m relay final at the World Athletics Championships at the Bird's Nest stadium in Beijing, Saturday, Aug. 29, 2015. Jamaica won the event (AP)

Jamaica's Usain Bolt crosses the finish line to win the men’s 4x100m relay final at the World Athletics Championships at the Bird's Nest stadium in Beijing, Saturday, Aug. 29, 2015 (AP)

Usain Bolt of Jamaica crosses to finish line to win the men's 4x100m relay during the 15th IAAF World Championships at the National Stadium in Beijing, China August 29, 2015 (Reuters)

Usain Bolt of Jamaica crosses to finish line to win the men's 4x100m relay during the 15th IAAF World Championships at the National Stadium in Beijing, China August 29, 2015 (Reuters)

Jamaica's Usain Bolt anchors their men's 4x100m relay team to victory at the World Athletics Championships at the Bird's Nest stadium in Beijing, Saturday, Aug. 29, 2015 (AP)

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