In the Netherlands, they call it the "voorstart." In Australia, it's the "marshalling room." In the FINA rule book, it's the "call room" and it's the place where the world's best swimmers are required to gather before each race.

There are actually two of them. The first call room is where the athletes get their suits, goggles, caps, and logos inspected, to make sure they comply with regulations. The final call room is where the swimmers assemble in lane order and gather their thoughts just before walking onto the pool deck. Or, as Chad Le Clos put it, "It's a room full of chairs where people get ready to go to war."

"The race starts there, actually," said Brazilian breaststroker Felipe Lima, 33.

Fans aren't allowed inside, but the public did get a glimpse of the interior during the 2016 Rio Olympics when an NBC television camera captured Michael Phelps' vicious death stare just before the men's 200m butterfly semifinal. His scowl seemed to be directed at Le Clos, the South African who had denied Phelps his third consecutive gold medal in the event by 0.05 seconds four years earlier in London. (Le Clos said he didn't notice Phelps' face until he saw the photos afterwards.)

Call room - Junior World Championships, Indianapolis 2017

Nevertheless, Le Clos said, "You see a lot of people breaking in there, quite scared. You can see fear in their eyes."

Femke Heemskerk, 31, of the Netherlands, however, does not get rattled. The three-time Olympian said that waiting in the call room, "is the one time I get calm. People in the call room are so hectic. If I'm [supposed to be] in Lane 4 and I sit in the chair for Lane 1, [the organisers] go crazy. I feel very calm compared to them."

Australian backstroker Mitch Larkin is mellow as well.

"For me to calm down isn't a big deal," Larkin said. And part of his attitude traces back to something he witnessed in 2012. It was his first Olympics; he had just turned 19; and he made the final in his lone event, the 200m backstroke.

"I walked into the call room, looked around and thought, 'There's eight guys here; three are going away with an Olympic medal."

It was Tyler Clary, Ryosuke Irie, and I remember Ryan Lochte walked in quite late, without his suit on. It was over his shoulder, towel around his waist, and he said, 'Uh, is this the 200 backstroke final?' I thought, 'Incredible! We're about to race in five minutes, you don't have your togs on, you're in an Olympic Games once every four years, and you're asking if it's -' I'll never forget that, just how casual he was. I still think - to this day - if he's that casual and it works for him [Lochte took bronze], it just shows that you don't have to get flustered and panicked."

Other call room behaviour is more demonstrative.

"At the 2018 European Championships in Glasgow," recalled Heemskerk, "a Hungarian guy beat himself everywhere on his body. I was like, 'Dude! What are you doing, beating yourself up?' Pretty soon, everyone was doing the same thing and it sounded like a concert."

"Yeah, sprinters do a lot of slapping," admitted Michael Andrew, 19 - a sprinter himself. "When we hit our legs, something about it wakes up our muscles, gets the blood flowing," he explained. "We all get going and some have a louder slap than others. When there's a silent moment, I have a friend who will whack his thighs as loud as he can. Everyone just like, 'What?'

The other violation of slapping etiquette, Andrew said, "is when someone gets caught slapping in synch with someone else."

Another tension breaker came in a French call room a few years ago. When the referee called a swimmer's name, Lima recalled, the athlete jumped from his chair and his head went through the ceiling and dislodged one of the panels. "It was pretty funny. It made a lot of noise," he said.

The key, all agree, is not to get flustered.

-- Even if officials in the first call room deem the flag too large on your cap - as happened to Andrew at the Kazan World Cup this year, forcing him to wear his cap inside out which, he said, was "SO weird," explaining that "the inside has a matte surface so it sticks to my head. To flip that outside doesn't feel as smooth [on the dive and the turns] when my arms are against it."

-- Even if your suit rips - as happened to Heemskerk at the 2009 World Championships in Rome, where the super-suits were so tight that hers ripped and wouldn't zip up before the 4x100 free final, yet she still helped the Netherlands win gold in world record time.

-- Even if the drawstring breaks - as happened to Larkin before the men's 200 IM heats at the 2013 World Championships when he pulled too tightly, and ended up with two broken ends in his hands. "I swam with a loose suit," he said. "It was probably one of the worst meets of my career, unfortunately."

But the minute the swimmers get onto the pool deck, the call room memories evaporate.

"When I walk to the block," Lima said, "I start to visualise my race right away and figure out every single meter I have to swim. Especially in the 50 breast; you can't make any mistakes."

On the starting block, the focus narrows.

"You just clear your mind," said Blake Pieroni of the U.S. "If you think, 'I don't want to blow my flip turn,' that's exactly what you're going to do."

"Even if it's loud," Le Clos said, "It's quite quiet for me, really."

Lima thinks about how he would like to react with his lower right leg, his back leg, because it's his first muscle to react to the gunshot.

Heemskerk, meanwhile, thinks about her right knee - her front knee - which is the first thing on her body to react to the gun. She has data to prove it. "We practice our starts a lot" in the Netherlands, she said, with the help of a high-tech start system which produces myriad analytical data. "When I think about my knee, I'm faster."

Andrew is a bit more expansive.

"The moment I get on the starting block," he said, "all I'm thinking about is the first 15 meters of the race: exploding off the blocks, flying through the water, waiting point-seven to the kick underwater to the 15 [meter mark] and breaking out at top speed. If I do all of that right, that sets me up for a perfect race," he said.