Monaco - Usain Bolt might have hung up his spikes, but there are at least two young American sprinters set to take up the mantle of the mighty multi-medal-winning Jamaican.

Christian Coleman, 22, and Michael Norman, who turned 21 on Monday, have risen to the top of the highly-competitive world of US sprinting on the back of a couple of impressive seasons.

Coleman this year set a world record of 6.34 over 60 metres indoors and won the world indoor title in March.

But injury struck the Tennessee-based athlete, who took world outdoor 100m silver in London in 2017 behind Justin Gatlin but ahead of Bolt.

"Last season was really special for me because I've never had an injury like that," he said of a nagging hamstring problem.

"To still push through that and work, run the times I did and come out on top and win the Diamond League, it was a special season and I was happy I was able to complete in that way."

Indeed, Coleman came back and ran a blistering 9.79 in his season-ending outing in Brussels, making him the joint seventh fastest man in history.

"I think 2019 will be even better," he said, although he said he would overlook the indoor season with an eye on the Doha world outdoor championships which has been pushed back to October because of the oppressive summer heat in the Gulf state.

"The sky's the limit. In perfect conditions, with a championship mindset and ready to peak, anything is possible. I don't even try to put a number on it and limit myself, I go out there to compete and to win," Coleman said.

It has been a similarly impressive season for Norman, whose 43.61 in Eugene was the sixth fastest 400m in history, coming shortly after he had broken the world indoor 400m record with 44.52.

"Looking at Doha, I'll definitely be targeting 400m," said the University of Southern California student who ran a 200m best of 19.84 in the Paris Diamond League meet in June.

Both Coleman and Norman, speaking ahead of Tuesday's IAAF Athletics Awards in which the former is a nominee, said it was an honour to be mentioned in talk about potential successors to 100m and 200m world record holder Bolt, the eight-time Olympic gold medallist and 11-time world champion.

"I was able to toe the line with him and had the opportunity to race against him and that meant a lot to me," said Coleman.

"Growing up and running track and field you look up to somebody like him, he's been an idol of mine, it's sad to see him walk away from the sport but there's an opportunity for guys coming in to push the sport forward."

Norman added: "Being compared to Usain Bolt is good in itself, but I want to reach a point where both of us are not being compared to a legend like Usain Bolt, but being known as the Christian Coleman or the Michael Norman.

"What Usain Bolt did to the sport was amazing. He really set a legacy and elevated the sport of track and field and set a new standard. 

"But now he's retired, I think it's time the young ones like Christian Coleman and myself take up that position and continue to push the sport in the direction it's being going for the last eight years."

Coleman acknowledged that Bolt's absence from the track had "changed the storyline and dynamic".

"Before, when Bolt was in the race, it was about who's going to get second. You just come and want to watch Bolt run, it's always exciting because you know he always puts on a show," he said.

US teammate Noah Lyles, himself just 21, is also in the mix after having run a startling 19.65sec over 200m in Monaco this summer.

"But now we don't really know who's going to win, we don't know who's going to get the gold medal," Coleman said.

"The excitement is still there and I think it will push the sport forward knowing there are so many young guys coming through."