Conner Mantz’s arms were shaking as he warmed up for the Olympic marathon trials in Orlando in February.
Mr. Mantz, 27, of Provo, Utah, looked over to his close friend, Clayton Young, who was stretching next to him. The two men had run more than 10,000 miles together. They had raced for the same prize money, fought for the same spots on the podium — and formed a bond so strong that other runners said they wished they could replicate it. They had supported each other through season-ending injuries, and pushed each other through grueling training sessions.
Their friendship has lifted both runners to the peak of their professional careers. Both believed they had gotten the other to the starting line that day. Now, they hoped to get each other to the marathon at the Olympic Games in Paris. They had a real shot: Mr. Mantz was a favorite to qualify, and Mr. Young was a strong contender.
If they made the team, their years of grinding out monotonous miles would be rewarded with the opportunity to represent their country, and an even better chance at financial security for their families.
But so much could go wrong in the two-plus hours it would take to complete the race, and Mr. Mantz and Mr. Young had daunting competition, including the four-time Olympian Galen Rupp and a score of other competitors who might surprise them.
By the time the runners approached the starting line, it was 61 degrees with 65 percent humidity — the kind of warm and muggy weather that makes a 26.2-mile race even more of a test. Mr. Young held a bag of ice in his hands in an attempt to stay cool. He and Mr. Mantz, both wearing white hats and black sunglasses, shook their limbs nervously as the countdown began.