'Sensible' to review marijuana status after Richardson ban: Coe

World Athletics chief Sebastian Coe on Tuesday backed calls to review the status of marijuana on the list of sport's banned substances following the suspension of US sprinter Sha'Carri Richardson.

Speaking to news agency journalists in Tokyo at the Olympic Games, Coe said it was "sensible" to look at the question of whether marijuana should remain on the World Anti-Doping Agency's prohibited list.

Rising sprint star Richardson was expected to be one of the faces of the Tokyo Games after a series of blistering 100m displays earlier this season.

However, the 21-year-old was ruled out of the Games earlier this month after being handed a 30-day suspension following a positive test for marijuana in the wake of her 100m victory at the US Olympic trials in Eugene in June.

Her case triggered a debate about marijuana's continued inclusion on WADA's banned list, with celebrities and fellow athletes criticizing the rule as outdated and unnecessary.

Coe said Tuesday he agreed with calls to review marijuana's status.

"I think it's not an unreasonable moment to have a review," he said. "It's sensible -- nothing is set in stone. You adapt and occasionally reassess."

Coe said the Athletics Integrity Unit, World Athletics' independent drug-testing watchdog, would look at the issue with WADA and other national anti-doping agencies.

Coe meanwhile expressed sympathy for Richardson's Olympic exile. "I'm sorry for her... We have lost an outstanding talent," he said.

"She will bounce back. It's a loss to the competition."

- Athletes need to 'dig deep' -

Coe, who is also a member of the International Olympic Committee, was speaking ahead of the start of track and field at the Tokyo Olympics on Friday.

The Olympics are taking place after a one-year postponement due to the Covid-19 pandemic with Tokyo still under a state of emergency.

Track and field will take place in an empty Olympic Stadium, with spectators banned from the Games. Coe said he expects athletes will be ready to adapt to the sound of silence.

"There's a double challenge here because the athletes became very used in the early part of the return to competition (from pandemic) to competing without fans," Coe said.

"The challenge this time is that they're in the last few months getting used to some fans in the stadium. So I think some are going to have to dig deep again and remember what it was that allows them to perform as well as they did without the stimuli of fans in the stadium."

The two-time Olympic gold medallist is also confident a new generation of stars will emerge in Tokyo in the first Games since the retirement of Jamaican sprint king Usain Bolt.

"The question I'm often asked is 'What does the sport look like post-Usain Bolt?'. Well, it looks healthy," Coe said. "And it looks healthy across a bandwidth of disciplines both in track and field, which is good."