Most aspiring athletes begin their journeys on the pitch, track, field, court or in the pool, depending on their sport - but for one young Londoner it began with a chance meeting.
"I was in a furniture shop in Orpington, south London, and the defensive line coach at the time approached me," said Nana Agyemang.
"He liked my frame and thought I had potential to play the sport."
The sport in question was American football, something Agyemang had never even played before.
The coach was from the NFL Academy, based in Loughborough, which scouts talent from all over Europe and Africa with a view to producing a generation of NFL stars from outside North America.
"At the time I was too young to apply for the academy, so he gave my mum his card and when I was 16 I came to the academy, applied to the trials, and then got in through that," he said.
Now 18, Agyemang is in his final year with the academy and has established himself as a defensive lineman.
He has grown to a height of 6ft 4in and gone from weighing 13st 3lb (185lb, 84kg) to 16st 11lb (235lb, 107kg) - and he hopes to increase that to 17st 11lb-18st 5lb (250-260lb, 113-117kg).
If all goes to plan, the next step on his journey will be securing a place at a college or university in the United States next year.
After that, the best players become eligible for a spot in the NFL draft and a chance to join one of the biggest franchises in the country.
"Football's football, as long as I'm still playing I'm still chasing the dream," he said.
Louis Rees-Zammit was a Wales international in rugby union but has earned a move to the Kansas City Chiefs through the NFL's International Player Pathway
Another way the NFL is attracting UK-based players is through its International Player Pathway (IPP) programme, which targets players at an older age looking for a change of career.
Former Wales international rugby union player Louis Rees-Zammit recently became the highest-profile name to do so via the pathway, joining the likes of Patrick Mahomes and Travis Kelce at reigning Super Bowl champions, the Kansas City Chiefs, this year.
And Rees-Zammit, who has 32 Wales caps, played an important role in convincing 18-year-old Rafael Blakstad to pursue a career in American football.
Blakstad began playing rugby four years ago and was part of the London Irish academy before moving to the Saracens academy, but he was unsure about putting aside his rugby ambitions to pursue a future playing American football.
When NFL Academy coach Steve Hegan asked him if he was free for a phone call one evening, he was surprised to find Rees-Zammit on the other end.
"I was absolutely stunned because he's one of my biggest idols," Blakstad, of Willesden Green, London, said.
"He said if he was my age and he had the opportunity to go to American football, even if he knew down the line he'd achieve all the things he has done in rugby, then he would have dropped it in a second at my age.
"That point really stuck with me. If this person who I idolise is saying this then why shouldn't I?
"It was an amazing call and the light bulb moment that made me realise this was something I wanted to pursue."
Head coach Steve Hagen addresses the NFL Academy on the pitch at Tottenham Hotspur Stadium
This year the academy has 72 players from 19 different countries and territories involved.
There are currently 19 academy alumni playing division one football in US colleges.
Former rugby player Travis Clayton was drafted by the Buffalo Bills in April, having spent time in the NFL academy and later joining the IPP programme.
A second academy is due to open in Gold Coast, Australia, in September.
Academy players know they are playing catch up to others who took up the sport much earlier in the United States.
But players who attend the academy from 16 and then move to the US could have up to seven years' playing experience by the time they finish college.
Head coach Hagen, who previously coached for the Cleveland Browns and New York Jets, said facilities in the UK were improving.
"America is the home of American football and they're going to do it the way it's supposed to be done but we're learning," he said at the Tottenham Hotspur Stadium after the academy's first training session this season.