The sport’s inclusion in the Summer Games has prompted many lap swimmers, used to competing in the controlled environment of pools, to cross over to open water, where the conditions are much less predictable.

Crippen’s career arc was emblematic of this new wave of competitors. He was a finalist in the 400- and 1,500-meter freestyles at the 2004 United States Olympic trials and competed at the 2006 Pan Pacific Championships in the 400 freestyle and the 800 freestyle relay before turning his attention to the open water.

At the time of his death, Crippen was one of America’s more seasoned open-water swimmers. He had earned a gold medal at the 2007 Pan American Games in the 10K event and two years later won a bronze at the world championships.

Educating the athletes in open-water events, Nyad said, is as important as safeguarding the courses. She said she had heard of open-water competitors employing the same race strategy in every race regardless of the conditions. She has heard of athletes being reluctant to hydrate when it is hot because they do not want to interrupt the rhythm of their stroke or because they believe they do not need to drink water since they are in the water.

“It’s partly the newness of the sport,” Nyad said. “In the New York Marathon, the runners know that if they step to the starting line on an extremely hot day, they are going to have to adjust and adapt their strategy and their expectations accordingly. I don’t think a lot of the swimmers drawn to these open-water events are experienced enough to know this.”

No member of the USA Swimming coaching staff or medical staff accompanied Crippen and other national team members to the competition in the United Arab Emirates, a lack of support Crippen addressed in an e-mail he sent to Chuck Wielgus, the executive director of USA Swimming, less than two weeks before the event.