The conquering kids of America, a fresh wave of Caribbean speed, yet another tireless troop of Africans and a Russian female version of Sergey Bubka. The young have taken over track and field, and not just in the United States.

Most are in their early 20s, some still in their teens. Several already own Olympic medals, and many will add to their collection at the world championships Aug. 6-14 in Helsinki.

They aren't as familiar as Marion Jones, Michael Johnson, Maurice Greene or Gail Devers, but give them time, because theirs might be the deepest and most talented generation in the sport's history.

Among the best of the U.S. contingent: Justin Gatlin (100 and 200 meters), Jeremy Wariner (400), Sanya Richards (400), Allyson Felix (200) and Kerron Clement (400 hurdles). Gatlin is the oldest at 23.

Internationally, start with 23-year-old Ethiopian Kenenisa Bekele, who broke the world 5,000- and 10,000-meter records in a nine-day span last year and is entered in both events in Helsinki. Bekele outran his famous countryman, Haile Gebrselassie, to win the Olympic 10,000 in Athens.

Bekele and a rising contingent of even younger Ethiopians will do battle with traditional nemesis Kenya, whose top runners include Isaac Kiprono Songok, 21, and Eliud Kipchoge, 20.

The fastest of the Caribbean sprinters, Asafa Powell of Jamaica, is doubtful for the worlds after tearing a groin muscle at the Crystal Palace in London on July 22. Powell, just 22, set the world 100 record at 9.77 seconds last month, but the fans at Olympic Stadium in Finland could be deprived of his much-anticipated showdown with Olympic gold medalist Gatlin.

The safest bet for a world record is remarkable Russian Yelena Isinbayeva in the pole vault. After all, she's broken it 17 times, four in the last month. At the Crystal Palace meet, Isinbayeva broke her world mark twice and became the first woman to clear 5 meters (16 feet 43/4 inches). Bubka, who was watching, set 35 world pole vault records.

"I would like to have 36 world records," Isinbayeva said. "It's my new goal."

She has no world championships, though, finishing third in Paris two years ago.

The IAAF, the sport's international governing body, promises its largest anti-doping effort, with more than 850 tests before, during and after the competition.

No sport has been tainted more by performance-enhancing substances than track and field, but those connected with the BALCO drug laboratory scandal won't be competing in Helsinki. Some weren't fast enough, others are serving suspensions. Kelli White, stripped of the 100 and 200 gold medals she won at the last world championships in Paris, has admitted steroid use, is cooperating with authorities and has become an anti-drug spokeswoman as she serves a two-year ban.

The young stars say they welcome the chance to put a shine on track's tarnished image.

"I hate it when people say 'Is he or she on drugs?' " said Richards, a 20-year-old who has run under 50 seconds in the 400 five times this year and beat Olympic champion Tonique Williams-Darling in Switzerland a month ago. "I know that with the new crop of athletes, and us running fast and doing it the right way, it will definitely reflect well on the sport."

Gatlin rebuts concerns about his coach, Trevor Graham, who sent the vial containing the designer steroid THG to U.S. doping authorities to show them what some athletes were using to avoid detection. Several of Graham's athletes in years past have tested positive for steroids.

"I know what to say no to and what to say yes to," Gatlin said. "If any allegations come up, I know it doesn't involve me, because I want to go out there and run the best race I can clean."

He also wants to show emotion but not the boorish, chest-thumping braggadocio often associated with his predecessors.

"I know I took on a responsibility of being a role model to young kids," Gatlin said. "When kids are watching, they're going to mimic. Obviously we want action and entertainment in track and field, but we don't want anything to go wrong like it has in the past."

The competition will go on without names that have dominated the sport over the past decade.

Dogged by doping suspicions despite her vehement denials, Jones was exceedingly slow this year, then at the U.S. championships Jones picked up her clothes and left the starting blocks just before the 100 preliminaries. Her agent said she had a hip flexor injury.

Devers has not been heard from all season, and at 38 finally may be ready to call an end to her long career.

Hicham El Guerrouj of Morocco, double Olympic gold medalist and four-time world champion in the 1,500, confirmed a week ago that he would not compete this year.

Olympic triple jump champion Christian Olsson of Sweden, Olympic 800 and 1,500 champion Kelly Holmes of Britain and defending world 400 champion Jana Pittman of Australia will miss the Helsinki competition because of injuries.

Greene, a three-time world 100 champion and 2000 Olympic gold medalist, will be in Helsinki, but only as a member of the U.S. 400-meter relay pool after pulling up with a hamstring injury at nationals.

For a reminder of the past, though, there is American Allen Johnson, at 34 seeking his fifth world title in the 110-meter hurdles. Johnson ran under 13 seconds for the 10th time in his career at the U.S. championships.

Among his chief rivals are a pair of those pesky youngsters. Liu Xiang of China is the reigning Olympic gold medalist and Ladji Doucoure of France has the world-leading time of 12.97.

Both are 22.

Justin Gatlin owns the 100-meter Olympic gold medal but Asafa Powell has the world record. Yelena Isinbayeva of Russia has set 17 pole vault world records. "I would like to have 36," she said, one more than compatriot Sergey Bubka.