
Marcio Teles of Brazil is escorted by medical workers after he falls down during Men's 400m Hurdles Semifinal on Day 4 of the 2017 IAAF World Championships at London Stadium in London, Britain, on Aug. 7, 2017. (Xinhua/Wang Lili)

Marcio Teles of Brazil is escorted by medical workers after he falls down during Men's 400m Hurdles Semifinal on Day 4 of the 2017 IAAF World Championships at London Stadium in London, Britain, on Aug. 7, 2017. (Xinhua/Wang Lili)