Race on to fill Bolt's shoes
In contrast in the women's event, Shelly-Ann Fraser-Pryce is bidding to win gold for Jamaica for the third time.
Lyles is focusing on the 200m, although he will face stiff competition from compatriot Erriyon Knighton, whose 19.88 sec in May at the age of just 17 broke two world 200m age-group bests previously held by Bolt.
Warholm's 20-year-old Norway teammate Jakob Ingebrigtsen is now a genuine rival to the strong East African contingent with his fast finish after setting European records at 1,500m and 5,000m and collecting continental titles.
"My goal is long term, I want to be able to win gold in major championships," he said.
"Last season was not about winning but about running fast. This year is the other way around for Tokyo. I need to make sure I will be at my best in Tokyo."
Technology boost
Middle- and long-distance races at global championships rarely produce records as they tend to be more tactical.
But the technological advances in running shoes means no record is safe at the moment, at least not in the presence of the likes of Dutchwoman Sifan Hassan, who will attempt an unprecedented treble of 1,500m, 5,000m and 10,000m.
Uganda's Joshua Cheptegei should be the man to beat as he tries a 5,000m/10,000m double.
Just 18 gold medalists from the 43 individual track-and-field events contested at the Rio Olympics five years ago will be in Tokyo.
The likes of world 800m champion Donavan Brazier of the USA and Olympic 110m hurdles champion Omar McLeod of Jamaica missed out on selection, while other stars, such as world and Olympic triple jump champion Christian Taylor, are sidelined with injury.
The US team boasts 35-year-old veteran Allyson Felix, who will become the most decorated female track-and-field athlete in the history of the Games should she add to her nine-medal haul.
AFP