BEIJING, CHINA - AUGUST 26: Wayde Van Niekerk of South Africa is stretchered off after winning gold in the Men's 400 metres final during day five of the 15th IAAF World Athletics Championships Beijing 2015 at Beijing National Stadium on August 26, 2015 in Beijing, China. (Photo by Lintao Zhang/Getty Images for IAAF)

BEIJING, CHINA - AUGUST 26:  Wayde Van Niekerk of South Africa is stretchered off after winning gold in the Men's 400 metres final during day five of the 15th IAAF World Athletics Championships Beijing 2015 at Beijing National Stadium on August 26, 2015 in Beijing, China.  (Photo by Lintao Zhang/Getty Images for IAAF)