When Michael Phelps was asked to be Team USA's flag-bearer at the Rio Olympics, he knew one thing: It was the first time in his Olympic career he could say yes.
In any other year, Phelps would have turned it down. The stress of the opening ceremony would have been too much. But this time, his racing schedule was different.
In 2016, he got lucky.
"Had he been swimming the 400 IM, which is the first event of the first day, he probably would not have done it, because [flag-bearing] just takes a little bit out of you," Bob Bowman, Phelps' longtime coach, said to ESPN.
While it's considered a huge honor to be chosen as flag-bearer, a substantial number of athletes decline to do it. For some, it adds too much physical stress -- eating into training and sleep cycles and inhibiting rest days. For others, the attention it brings is an added burden during a time when they want to focus, the world is instead focused on them.
Tennis champion Maria Sharapova wanted to be Russia's flag-bearer at the 2008 Beijing Olympics, but Russia's tennis chief, Shamil Tarpishchev, advised against it.
"I don't want her to spend three or four hours in hot weather waiting to march in the opening ceremony. We want her to be fresh, not tired, during her matches," he said at the time.
Australia's four-time Olympian and three-time-gold-winning rower Drew Ginn turned down flag-bearing responsibilities in 2012 because he had always skipped the opening ceremony to prepare for his competition, and didn't want to change his routine.
In Rio, Philippines' table tennis star Ian Lariba, who was competing the following morning, started off as the flag-bearer for the first minute, then passed it off to his teammate and first-time Olympian, taekwondo jin Kirstie Elaine Alora.
This year, with Tokyo expecting 90-degree weather for the opening ceremony, U.S. flag-bearers Sue Bird and Eddy Alvarez will have specially designed cooling jackets to ensure they don't get overheated or dehydrated during the ceremony.
What is the flag-bearing experience like -- and how does it affect athletes during the biggest competition of their lives? We talked to those who have done it before.
"I was more nervous about [being a flag-bearer] than I was for my race, I think."
At the 2018 Pyeongchang Olympics, luger Erin Hamlin had been voted as the flag-bearer just days before the opening ceremony. But after the first few minutes of utter excitement upon hearing the news, her mind reeled with questions: What if the flag is too heavy? What if my arms feel sore after holding the flag? What if my wrist injury flares up?
"I had a bad wrist at the time, and so I had already been treating it all the time to make sure it didn't affect me during my race," Hamlin said.
Her trainers didn't seem too concerned, but asked her to listen to her body. She wasn't competing the next day, and didn't have any training sessions scheduled for early in the morning. If that had been the case, she'd have had to have a longer conversation with her coaches.
She decided to do it. "It's an honor to be selected by your team," she recalled.
An hour before she had to leave for the Olympic Village and wait in the designated area for flag-bearers -- a wait time of about three hours -- she asked her trainers to tape her shoulders and wrists for added support. She wanted to do everything in her power to mitigate the extra stress her wrists might bear as a result of holding the flag pole.
When the moment finally came, the pole felt oddly light, made out of plastic PVC, but the flag whipped around in the wind. Every time the flag moved, she readjusted her position, waving the pole to make sure the flag was clearly seen.
"I could have easily just held it really still, but I didn't want to," Hamlin said. "Because I think I was waving it the whole time, it was like doing a workout for my wrist."
When she finished her lap around the stadium, one of the organizers took the flag from her. If she had to guess, the flag-bearing part of the experience lasted about 15 to 20 minutes.
"I definitely felt fatigued the next day -- I could feel that I had done something outside of my training schedule," Hamlin said.
If she had to compete the next morning, there's no way she could have said yes to flag-bearing, she said. The men's luge team members skipped the ceremony entirely because they were competing the next day, Hamlin said.
It's not just the actual act of flag-bearing that worries coaches. It's the added stress to the athletes' already stressful schedule, said performance coach Brett Bartholomew.
"They're thinking, 'Is this going to be the thing that breaks the camel's back?'" Bartholomew said. "When it's such a huge event, and they've spent so much time focusing on it and getting ready, you know, they just want their athletes to focus and sleep and rest and visualize. They don't want anything else."
Even though Phelps wasn't competing the day after the opening ceremony, the Rio Olympics organizers worked tirelessly to make the logistics of flag-bearing easier on him, Bowman said.
"I actually think it was not the flag that was the big factor," Bowman said. "It was the walking and being on your legs -- that was our concern: How long he was going to be on his legs and how that was going to factor into things."
While it usually took three to four hours of wait time before the opening ceremony, Phelps was asked to come in only an hour in advance so he wasn't standing around and losing energy that way, Bowman said. Even while he was there, he was off his feet most of the time. And after one lap with the flag, Phelps left early from the ceremony, minimizing his stress and allowing him time to go to sleep on his normal schedule.
Two days later, Phelps swam the 4x100-meter freestyle relay and won his first gold medal at the Games. He went on to win five gold medals and one silver in Rio, cementing his status as the greatest Olympian of all time.
How the athletes perceive the role is also important, Bartholomew and Bowman said. Some athletes love the attention and cherish the opportunity. Those might get a lot out of the process, and it might ignite them to do better in their competition.
That was the case with Hall of Fame basketball player and coach Dawn Staley.
By the time the 2004 Summer Olympics in Athens rolled around, Staley had already helped U.S. basketball win two gold medals. Previously, at the opening ceremony, she always hung out at the back, with her basketball crew. She had no idea who was at the front of the Team USA line or what the responsibilities were.
When she heard she had been picked to be the flag-bearer at her third -- and what would be her final -- Olympics, she was moved, and exhilarated.
"They told me as their captain, 'We want you to validate yourself, basically for all you've done and what you do for the community,'" Staley said.
That felt like the fresh jolt of energy she needed to carry her through the Olympics. She walked into the stadium in Athens grinning and holding the flag high. She looked the opposite of nervous. She looked radiant.
"It's one lap around the stadium! If anything, it's going to help your legs get a good workout in," she said. "The adrenaline puts you over the top -- and then afterwards, you're on cloud nine! I won't ever be able to duplicate that feeling."
She took that feeling to her games and helped the U.S. team take home another gold medal in basketball, her third.
While some athletes revel in the attention, others find it unendingly taxing. Two-time Olympic fencing champion Mariel Zagunis usually had a set routine the minute she reached the Olympic Village.
"I put my head down, disappear into my sport and don't come out til the gold medal is mine," Zagunis said.
When she was chosen as the flag-bearer at the 2012 Olympic Games in London, her third Olympics, her first reaction was surprise. She was not the big-personality athlete she thought they'd go with. Her next reaction? Nervousness.
She suddenly had a barrage of messages -- interview requests were granted and on-camera appearances were slotted into her day's already jam-packed schedule.
She finished training and ran over for media interviews, all the while wondering how this attention was going to take away from the competition, she said.
A straight line obviously could not be drawn between flag-bearing and winning an Olympic medal, Zagunis said, but it is interesting to note that in the four Olympics she has been a part of, the London Olympics is the only one where she didn't medal. She lost to South Korea's Kim Jiyeon 15-13 and then in the bronze-medal match, lost to Ukraine's Olga Kharlan 15-10. At the next Olympics in Rio, she helped win a bronze medal in the team fencing event.
In Phelps' case, if he had been asked to be the flag-bearer at the 2008 Olympics -- his second Olympics, where he won a record eight gold medals -- the answer would have been "no way," Bowman said.
"He just could not have done it, because the program was too big and it meant so much to not just him but to the rest of the world," Bowman added.
Four years later, with a different schedule and less to prove, it became possible.
"In Rio, he had come back from what we thought was his retirement, and he was seeing the sport in a different way," Bowman said. "He wanted to fully embrace everything about the Olympics, so that's what made this decision much easier."