“I was doing triathlon for fun, but I looked at some times and thought, 'I might be able to do something here'”
Clare Cunningham2009 world champion in Tri 4 category
Take the women's Tri 4 category as an example. Faye McClelland won last year's world title in New Zealand, finishing ahead of GB team-mate Clare Cunningham, herself the world champion in 2009.
This year, McClelland, 34, has taken time off to complete her dissertation. In her absence, newcomer Lauren Steadman won the British and European titles, with Cunningham not far behind.
Cunningham, a Paralympic swimming champion at Barcelona 1992, says the UK is reaping the rewards of reacting the fastest when paratriathlon was awarded its place at the Games three years ago.
"We are part of the UK Sport funding structure and much more professional in our outlook - in the way we approach our training and our competition," the 36-year-old told BBC Sport.
"That was evident at the Europeans this year. We were by far the best-prepared team."
At 20 years of age, Steadman has already been to two Paralympic Games as a swimmer. Whereas Cunningham dropped swimming after Atlanta '96 and waited more than a decade to be tempted by triathlon, Steadman made the switch straight after London 2012.
"Everybody reaches a point where they're ready to take another step," says Steadman. "I enjoyed my swimming career, but not as much as I used to.
Paratriathlon events at Rio 2016 have not been confirmed, but the six classifications recognised at world level are:
Severe leg impairment, including above-the-knee amputation
'Les Autres', a category including athletes with cerebral palsy, muscular dystrophy and multiple sclerosis among other conditions
Arm impairments (the category contested by Cunningham and Steadman)
Moderate leg impairment, for example amputation below the knee
"I had a big rush in swimming, but this one just seems bigger in triathlon. Combining all three sports? I love it."
Cunningham, who won four silver medals and a bronze as a Paralympic swimmer, says: "By 1996 my love for swimming had just gone. I really did think that was my elite-performance days over.
"[Then] at the end of 2008 I'd just got married, we'd had six weeks' honeymoon, I came back to work and needed something in my life - something to get excited about.
"I was doing triathlon for fun, but I looked at some times in the world and thought, 'Ooh, actually, with a bit of training I might be able to do something here.' In 2009, I was British, European and world champion."
Going from a standing start to holding those three titles, inside a year, implies the sport could be more competitive. But Cunningham says that is changing.
"This is a really exciting phase now that we've got the Rio Paralympics and a lot of new, young talent coming through," she says, using Steadman - who beat her to this year's British title - as an example.
"Lauren has come directly from a swimming background. She already has that professional outlook in the way she trains and approaches competitions.
"The fact she can swim very, very well means she has set a new marker down for us and what we've got to be doing in the swim.
Meet some of the GB Para-triathlon team targeting Rio gold
"It's just going to make us better in the UK, which is great for the British team, so that when we go on the world stage we are by far the best in our category."
Surely that could be frustrating, though? Here is Cunningham, a winner of every major title in the same year, watching McClelland and Steadman steadily erode her chances of victory, not to mention foreign rivals.
"Yes, it might be a bit frustrating, but as an athlete I can do one of two things: I can either rise to the challenge and see it as an opportunity to develop myself, or I can leave the sport and complain," she reasons.
"Ideally my main competition might be from outside the UK - it makes it harder to make the team each time - but at the same time, I know I will benefit from having that competition in the long term."
Steadman says: "If anything, I'm learning from Clare. She's been around doing this so long and I feel like a newbie, a bit wild. I have the competitive drive and experience of being an athlete as a swimmer, but there are lots of things I've got to learn."
Cunningham, McClelland and Steadman are the three British representatives in a 12-woman Tri 4 field at paratriathlon's World Championships in London's Hyde Park on Friday. Steadman, the only one without a world title to her name, is the in-form athlete.
"I'm just getting as much as I can out of each race," she says. "For the Worlds I'll have a bit more knowledge, but my main goal is that medal in Rio."
"When I saw the men's triathlon at London 2012," recalls Cunningham, "the support they had, the course - the pressure on the guys to win, and the fact that they did and the way in which
Alistair Brownlee won
- that was very inspirational. Under all that pressure, they delivered on the day.
"It's really exciting to think that there will be a triathlon in the Paralympics in Rio for the first time and that's groundbreaking. It'll be really exciting to be involved in the first-ever Paralympic triathlon. I just have to make sure I'm on the team."
World Triathlon Series: London
Women's race: Saturday 14 September: 08:30 BST, BBC Red Button/online; Highlights - 14:30 BST, BBC One/online
Men's race: Sunday 15 September: 13:00 BST, BBC Two/online
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