Wayde van Niekerk File Photo: Julio Cortez/AP

Record-setting Wayde van Niekerk could be the athlete to take over track and field from Usain Bolt, according to the Jamaican sprint star himself.

Bolt is in his final season of a glittering career that has seen him win eight Olympic and 11 world gold medals with a charisma and charm that have made him one of the most recognisable faces in world sport.

The massive void his absence will leave looks most likely to be filled by South African Van Niekerk, whose personality remains considerably less than Bolt's larger-than-life version.

The 24-year-old smashed Michael Johnson's world record for the rarely-run 300m at the Golden Spike meet in Ostrava on Wednesday, clocking 30.81 seconds.

It was the second time Van Niekerk has bettered Johnson, having set a new world record of 43.03sec when winning Olympic 400m gold in Rio last year.

Asked whether the South African, also the current world 400m champion but an athlete who has clocked 19.84sec in th 200m and 9.94sec in the 100m, is his likely successor, Bolt was definitive.

"Yeah for sure," he said. "I think he really wants to be a sprinter because he's set a personal best in the 100m this year.

Wayde Van Niekerk wins the gold medal in the Mens 400m final, breaking world record during the 2016 Rio Olympic Games. Photo: Gavin Barker/BackpagePix

"He's shown he's ready for the challenge. He's really down to earth, he's really humble, he's a great person.

"He listens and wants to be good and if he continues like this he'll take over track and field."

Stiff back

Bolt was far from his convincing self in winning the men's 100m in a modest 10.06sec, partially blaming a stiff back.

"It wasn't that good a race. It was pretty slow, I'm just getting into my rhythm. I've got some work to do, things have been going smooth," the 30-year-old said.

"It's just my back, as always. It's always an issue," he said, shortly before doing two long jumps before the remaining crowd and media.

"As long as I stay injury-free that's the key thing."

Bolt added: "After the race there were mixed feelings because I know it wasn't the perfect race but I got it done."

Asked if there were any concerns about appearing at the London world championships, just 35 days away, Bolt said: "No, I'm going to see my doctor soon so I know he will fix every problem.

"All I need to do is train hard and just focus on getting myself in some shape.

"One run really doesn't matter to me. It always comes down to the championships, so it's about me getting into great shape and that's the focus now, getting into running shape and to make sure I feel good after I run."

Bolt insisted: "I never worry. One thing is that if my coach is not worried, I'm not worried."

"I need to go to the doctor, get everything checked out, make sure everything's smooth and just continue training, pushing hard and then when (the July 21 Diamond League meet at) Monaco comes, I'll see where I'm at and what I need to to do."