It is not possible to overstate the surreality of the post-race moment. Olympic-sport athletes in the United States are given a tiny quadrennial window in which to make good on endless hours of training and boundless dreams. On this day, Hall, Ritzenhein and Sell had slipped through the opening. For Hall and Sell it is their first Olympic team; for Ritzenhein his first in the marathon. They had seized a very potent reality, only to be confronted by a much larger one.

"I was incredibly delighted after the race,'' said Ritzenhein. "But then I heard this and ... it's just running. And there are definitely more important things than running.''

The elite running community is a small town in many ways; every top runner in the U.S. has connected with most other top runners. But Hall was particularly close to Shay. Hall's wife, Sara (Bei) Hall, ran at Stanford with Shay's wife, Alicia (Craig) Shay, and Sara Hall was a bridesmaid in the Shays' wedding last July 7 in Jackson Hole, Wyoming. In the winter and spring of 2006, Hall and Shay trained together in Mammoth Lakes, California.

"I trained with Ryan, he inspired me,'' said Hall. "I can't even think about my race right now. To lose a friend today....''

Distance runners are a tough, strong-willed subset of athletes. They endure uncommon levels of pain, and not just in races, but nearly ever day. And among his peers, Shay, a native of Michigan who ran for Notre Dame and was the U.S. marathon champion in 2003, was regarded as one of the toughest of the tough. "He trained harder than anyone,'' says Ritzenhein. "He was a workhorse. He put it on the line every day.''

Sara Hall recalled once seeing Shay collapse on a treadmill during a VO2 Max test, in which runners are instructed to run literally to the point of collapse to determine top end lactate thresholds. "You're supposed to go to your max, but his max was further than most. He had an incredible ability to tolerate pain.''

Shay's coach, longtime trainer Joe Vigil, told John Meyer of the Denver Post, "Ryan Shay was the epitome of an athlete. He was everything you'd hope to find in an athlete. Committed. A passion. Trained hard. Was true to the sport. Intelligent. He had everything.''

The disconnect associated with Shay's death is almost paralyzing. It is tragically common for ordinary citizens to collapse and die while engaging in endurance activities, often with heart disease that had lain in wait. Shay was among the fittest people on the planet. "He encouraged me to challenge him,'' Vigil said. "He never had any problems.''

Shay was running at what should have been a comfortable pace very early in a long race. He passed 5,000 meters in 16:53, a pace he has surely run many, many times in training. A little more than two miles later, he lay prone on the pavement. Kathleen Jobes, an elite runner who was watching the race, came upon Shay shortly after he fell and saw several spectators administering CPR. "Seeing him there, and then realizing who it was, it's something that I won't be able to forget,'' said Jobes.

An ambulance arrived and emergency medical technicians continued to work on Shay, but the ambulance did not rush to the hospital. "It was apparent what the situation was,'' said Jobes, whose thoughts turned immediately to Shay's wife.

Competitors were told of Shay's passing when they finished the race. Keflezighi and fellow 2004 Olympican Alan Culpepper were together when they heard the Shay had died. "I cried when they told us,'' said Keflezighi, who again began to cry while talking with two reporters when recounting the story.

Shay's peers will be left now to make sense -- and peace -- of a runner's death. "I think it just shows how fragile life is,'' said Sara Hall.

On the day before the marathon, the Halls and the Shays had run together in Central Park. The men went an easy four miles, the women kept going a little further, because they did not have a championship marathon on the next day. It was a beautiful day in New York; cool but not too cool, cloudless and calm. It was a day to embrace life.

A day later Ritzenhein sought an answer and came up empty. Perhaps there will soon be a medical explanation for Shay's passing, but there will never truly be an answer. "Some things,'' said Ritzenhein, "are unexplainable.''