Spirit of innovation vital for future - Coe

World athletics chief Sebastian Coe said Sunday track and field will continue to experiment with innovation as the sport attempts to win back fans after being engulfed by the worst scandal in its history.

Speaking as the curtain was set to come down on the World Indoor Championships, International Association of Athletics Federations (IAAF) president Coe said changes introduced in Portland could feature at next year's World Outdoor Championships in London.

"Some of the things that we've road-tested here you'll see in other formats," Coe told AFP.

"And you'll see evidence of that in London 2017 and beyond."

Changes introduced in Portland have mostly involved the field events. In the shot put, long jump and triple jump, the field was whittled down to the top four athletes for the final attempts in each event.

The changes were made in order to ensure that the entire focus of the crowd was on the finale of each event as it took place.

While the innovations appeared to be well-received by spectators, they were not universally embraced by athletes, with New Zealand shot put star Valerie Adams complaining on Saturday about delays in her event.

However Coe said Sunday the spirit of change represented the future.

"It's really important that when we have the opportunity to road test innovation we take it," Coe said.

"Not everything we're going to do is going to work. But I'd rather be in a sport where we sometimes have to say 'Okay, that didn't work quite as planned' rather than sitting there sclerotically for the next 10 years.

"You aren't going to see growth and development of the sport like that if you don't innovate."

Coe meanwhile insisted that the absence of Russia in Portland -- banned from competition after last year's World Anti-Doping Agency (WADA) report which uncovered a systemic doping regime in Russian athletics -- had not tarnished the meeting.

Commenting on the Russian absence, Coe replied: "It's a sad moment for our sport ... but it hasn't stopped this from being a fantastic athletic experience for spectators and athletes alike."

Coe said the attendances at the Oregon Convention Center -- which had been close to sold out over the four days of competition -- indicated that the sport retained support despite drugs and corruption scandals.

"It shows you that the sport is still very strong," Coe said.

"Nobody is denying the challenges that lie ahead to regain trust but this has been a pretty good start."