Action from the start of the 400m (Getty Images) © Copyright
Preview Nairobi, Kenya

Preview: boys' 400m – IAAF World U18 Championships Nairobi 2017

While he has not yet displayed his best form this year, Musa Isah of Bahrain will be among the key contenders for the one-lap crown.

The rising Bahraini star reached the semifinals of the World U20 Championships in Bydgoszcz last year, at the age of 15, and set a personal best of 46.95 in Tlemcen.

Isah, however, has not gone faster than 47.31 this season, and he will have a battle on his hands if he hopes to return home with the gold medal.

Two other boys in the entry lists have run faster than 47 seconds, with Melkamu Assefa of Ethiopia (46.85) and South American U18 champion Bruno Benedito da Silva of Brazil (46.91) also entering the event among the main contenders.

Six other boys in the line-up have run under 48 seconds, including the Jamaican duo of Anthony Cox and 15-year-old prospect Antonio Watson, who have both clocked 47.05 this year, suggesting a hard-fought battle is on the cards for podium places.

Wesley Botton for the IAAF