It is a brutally cold February morning in east Manchester. A freezing wind is blowing around SportCity, the sort of wind that makes you squint your eyes and try to retract your head into your shoulders like a frightened tortoise.
It feels an awful long way from the last August, let alone the beaches and steamy heat of Rio. No matter. It is here that Laura Trott suffered en route to her two Olympic golds in London, and where she is once again destroying her lungs and legs in preparation for more.
"It hurts so badly," she says, perched in the seats above the velodrome she has just lapped at dizzying speed, hundreds of times, like some relentless clockwork toy.
"It's like your legs are getting squeezed. You try to fight against it, but it's horrible, and they're just getting tighter and tighter. You're going slower and slower.
"You go flat out again, swing up, and then the motorbike pacing you comes back underneath and you have to sprint just to get back on his wheel. Your legs are absolutely killing. But you have to deal with it in a race, so I have to deal with it now."
If the body is tortured, the mind is anything but. Trott, just 20 years old but already the break-out star of the British track team competing at the World Championships this week, is one of sport's incorrigible enthusiasts.
There are those for whom elite sport is a career. There are others, like Trott's former team-mate Vicky Pendleton, who even admit to to feeling asphyxiated by pressure and expectation.
Not Laura Trott.
"I absolutely love it, every second of it," she says, eyes wide and face alive. "My routine is come in, sit with the mechanics for an hour just talking absolute rubbish, and then ride. Everyone is happy in here.
"I love getting on my bike; the feeling of achieving something every day. That feeling when you win, and making people happy… I love that even more.
"The pain? You have to get past that lactic barrier to eventually feel good. When I've sprinted, and then the race slows down and you've got through it, it's a great feeling."
It is not that Trott has been protected from fortune's slings and arrows. Born six weeks premature with a collapsed lung, she spent the first weeks of her life in intensive care. As a child she suffered serious asthma; at the exact moment she first sat on a bike, aged four, her big sister Emma was crashing and breaking her leg at the bottom of the same hill.
As a young girl she preferred trampolining to her bike, only to be forced to give it up after repeatedly passing out in mid-air: "I kept getting dehydrated during sessions, because you had to go out of the room to get a drink, and I was like, 'Nah, I'll carry on bouncing'."
That she got into cycling at all was pure fluke. Her mother, Glenda, wanted to lose weight. While chatting to another mother at her daughter's swimming club, she was told about a cycling club in the nearby town of Welwyn. When she went along for a look, her two girls went with her.
"I remember the first race I won," says Trott. "I was 11 and we'd do Friday night track meets through the summer. You do a handicap race with the big boys. There was a boy who used to win everything, week after week, but they handicapped me so far around, and my dad gave me such a big shove, that I actually won.
"I was like, 'Wow! I've won £2!' But it was actually seeing my mum and dad so happy that I had won a race that made the difference. From then on I wanted to go back. 'Mum, can we go Saturday?', 'Mum, can we go Sunday?'"
You might have expected Trott to have been wrecked by nerves when, just eight years later, she lined up in London chasing team pursuit and omnium Olympic gold.
That would be to misunderstand what drives her. she set world records in every round en route to pursuit domination. Then, in the multi-event omnium, she produced a blistering 500m time-trial to snatch gold from US favourite Sarah Hammer.
"I was sitting there with my coach and I said to him, what numbers do I need to see on the board? I want to know whether to celebrate.
"I wanted it so much. I didn't want to let one stupid thing, one race, let me down."
Pendleton put much of success down to the work she did with British Cycling's mental guru Steve Peters, who has also had great success with Chris Hoy and Ronnie O'Sullivan.
Peters famously talks about taming the "chimp" that assails you in moments of great tension. If there is a monkey on Trott's back, he is of the small, cuddly variety.
"I didn't really work with Steve, because I didn't feel I had to. I do take it seriously, but it's fun. I do it because I enjoy it.
"The outside world doesn't bother me. People can say what they want, and I can read all the articles and see what they say, but I'll just get on with it.
"I loved the feeling in the Olympic village and the velodrome. It felt like everyone was driving me on, rather than, 'Ooh, she has to win'."
Strange things happened after her two golds. She had to buy her sister a car, after making a jokey pledge 12 months before. She was pictured on the front pages of national newspapers, kissing her new boyfriend - - Jason Kenny in the stands a few rows behind David Beckham. Then Prince Harry sent a text message, asking if the pair of them wanted to watch the volleyball with him.
Trott adds: "Just to top it off, he says, 'Can I have my photo taken with you?' and holds his phone out. So me, Jason and him are in this photo. It was the most surreal moment ever.
"I know a lot of athletes had that real low after London, but not me. It was weird - I had media sitting outside my house, wanting a photo, and I thought, 'This isn't me'. I still felt like the same person but I took all the media and appearances I wanted and then went on holiday.
"When it did all get too much I just got back on my bike, because it was the only thing - this will sound stupid - but it was the only thing that made me feel normal. The only thing I do each day is get up, eat breakfast, and go out on my bike. Go back, go out on my bike, and go to bed."
Trott credits the three men in her life with keeping her steady. Her father Adrian made the early sacrifices; her coach Paul Manning deals with training ("I trust that man with my life. He just gets it") and Kenny understands it all ("If I was in a relationship with someone outside cycling, just imagine how hard it would be - I'd have to explain everything from scratch").
She says she has at least two more Olympics in her, maybe more, which would give her every chance of being Britain's most successful female Olympian ever.
Is there a danger that such a long stint in the saddle, so many millions more laps of the velodrome, could dull her passion?
"People tweet me pictures of their kids, saying they're shouting 'Go Trotty go!' I absolutely love it. I went down to my old cycling club and the amount of kids down there was absolutely amazing - 'Can I do a 500m like you?'"
"I love that. That's what Vicky and Chris did for me and I want to give that back to the next generation.
"It isn't a job to me but if it did feel like one, it would be a dream job. All I do is ride my bike for four hours a day and then lie on the sofa for the rest of it. I don't feel like I'd ever fall out of love with it."