There will be an element of relief tomorrow morning when Rebecca Adlington leaves the call room tucked beneath the stands of the London Aquatics Centre and heads for the blocks that squat at one end of the pool. She is back in her natural environment.
Four years ago she made the same short journey in the Water Cube in Beijing. Then she was unnoticed. She will not be tomorrow. Not as Britain's most successful swimmer in Olympic history, as one of the most recognisable faces of the home team at 2012 and as one of the host nation's best chances of a gold medal, not only in the pool but across the Olympic programme. No British swimmer has ever successfully defended an Olympic title. That is the size of Adlington's task.
"It all starts again," says Bill Furniss, the man who has coached her from the very start. He will be poolside again tomorrow for the 400m freestyle, the first of the two freestyle titles she claimed in 2008. "Winning an Olympic title is one thing, to defend it… it's a very small percentage of Olympians who can do that. Rebecca is already in uncharted waters – she's a double Olympic champion and she's defending in a home Olympics, which is awesome."
In Beijing, Adlington was not expected to win a medal and won two golds. In London, Adlington is expected to retain those two Olympic titles.
"You can't just go and get a gold medal like you're going to get a drink," says Adlington. "It is so hard. This is one of the hardest sports to medal at. I don't think people appreciate quite how hard it is. It is hard just to make the final. The difference between winning and coming eighth is ridiculously small. It can be anybody's. I nearly missed the final of the 400m last year at the worlds. Who knows what is going to happen this time? I hope to God I make the final."
The 400m is the title she will find the hardest to defend. Despite her fear of missing the World Championship final last year she eventually won silver and has posted the second-quickest time this year. She is the watched woman and the likes of Federica Pellegrini and Camille Muffat, this year's pacesetter, are more than capable of finishing ahead of the Briton, but Adlington remains the one to catch.
"She's in great shape," says Furniss. "We've had a really good year. We've probably lost two days through sickness or injury in the whole year. Preparation-wise, I think she's swimming very, very good. Some of the training times are at least as good as, if not better than, they were before Beijing."
Adlington's life has been transformed since Beijing, and it has not always been an easy transformation, nor one she has always been comfortable with. She has suffered from that peculiarly hurtful British attitude towards fame – thrusting adoration and attention on someone and then detesting them for it. There were difficult times in and out of the pool.
"She is much more mature now," says Furniss. "She knows that's all going to happen. She can't stop that happening. She's thankful that there are so many people who want her to do well, but at the same time it brings with it…" His voice trails off for a moment. "You've got to handle that. What doesn't break you, makes you stronger and that's what happened post-Beijing. It was a very difficult time and she got through that. She is lot stronger now because of that.
"Mentally, it took her some time to learn to live with being a household name all of a sudden. The whole expectation thing was cranked up, her expectation was cranked up – it was life-changing. She was only 19 when that happened. It was a steep learning curve. But she can handle that now, she is more relaxed, more in control of herself. Then she was a girl, now she is a mature woman who knows her own mind."
Being four years older has not only changed her mentally. Furniss and Adlington have altered her training schedule, introducing more land-based training. Adlington has been doing two sessions of gymnastics a week, working with two of the British coaches.
"What she could do at 19, she can't do in the same way," says Furniss. "Some things she can do a lot better, but the training regime she does is punishing – it's brutal. So we've had to alter that slightly as she's matured. She's pretty consistent: 20 hours in the pool a week, 10 two-hour sessions. She goes 70km (43.75 miles) a week more or less every week.
"We have changed her programme so it's far more gymnastic-based – to improve her agility and her leg strength and particularly her work around the walls on the turns. It was an area I felt she could improve on. What you're looking for is marginal gains all the time – that could make the difference. Those extra few tenths or even hundredths of a second, that can make that difference."
What makes the ultimate difference for Adlington, though, is ultimately fairly simple; she is a natural in the water, more technically gifted, believes Furniss, than anyone else who will climb on to those blocks in London, be it Michael Phelps or Missy Franklin. It is her environment.
"She has amazing stroke length, that's the first thing," says Furniss. "She's got this ability to keep a line in the water – nothing deviates, it's very compact, very precise. Most people increase speed by increasing the rate. Rebecca actually increases her speed by lengthening her stroke – her rate can drop, which is uncanny – you don't see that.
"She's just got an amazing ability, an amazing feel for the water. The gift she's got is she's very focused, very technically aware. I can say to one swimmer, 'Do this', and six seconds later she's not doing it.
"I say to Rebecca, 'Do this', and six years later she's still doing it. She's just got this amazing ability to concentrate, focus and apply herself. If you were to describe a textbook freestyle there is nobody better – male or female. It's perfect. It's everything you want."
And meet her rival who is scared of the deep end...
It's one of the favourite curiosities of the British swimming team that Rebecca Adlington is afraid of the sea. Federica Pellegrini can better that – Adlington's great rival in tomorrow's 400 metres freestyle does not like deep water. Two years ago she had to be pulled from the pool by her coach during a training session after a panic attack.
Pellegrini and Adlington are the same age, both 23, but they could not be more different. Adlington is a laid-back competitor who pays not the slightest bit of attention to what is going on around her. She has a steady home life and has been with her coach, Bill Furniss, from the start of her career.
Pellegrini is on her fourth coach in the last three years. Since Alberto Castagnetti, her long-time mentor, died suddenly of a heart attack the Italian has chopped and changed – including a spell based in Paris with Philippe Lucas, who oversaw the success of the French freestyler Laure Manaudou.
She is now back in Verona, where last year she chopped and changed boyfriends. Last summer she broke off her engagement to Luca Marin, a fellow swimmer. Her new partner is Filippo Magnini, another Italian swimmer.
When she gets in the pool Pellegrini, one of Italy's highest-profile sports star, has enormous ability. She was the first woman to break the four-minute barrier in the 400m and won a silver in 200m free in Athens aged just 16. But her ability to cope under pressure remains suspect.
She was a huge favourite going into the 400m in Beijing and finished fifth. She later won gold in the 200m and shone in the 2009 World Championships. But her preparations for London have been disastrous. She failed to make it out of the heats at the European Championships in May. Her best time in the 400m this year puts her ninth in the world rankings.
Nobody knows quite what to expect from Pellegrini. She arrived in London last weekend. "For the moment I am quite calm," she said, "although there are a few days to go."