The size of the contingent is testament to the Army's World Class Athlete Program, a detachment that allows soldiers to essentially train full-time in their sports. Credit is also due to a provision of U.S. law that offers expedited citizenship to immigrants who serve in the armed forces.
Paul Chelimo, 25, is one of four Army runners to make the U.S. team. All four were born and raised and started running in the highlands of Kenya. They won athletic scholarships to American universities. After college, they enlisted in the U.S. Army, which is open to non-citizens with legal residency. Chelimo signed up in 2014.
"Actually, my main goal was to represent the United States. Being an Olympian is the best way to represent the United States," he said. "That was the best program because I could do my career as a soldier and also focus on my talent."
Chelimo was part of the crowded field at the start of the men's 5,000 meters (3.1 mile) at the U.S. Olympic Track and Field Trials, held July 9 in Eugene, Oregon.
Most runners wore brightly-colored uniforms featuring their shoe company sponsors. But Chelimo was in beige, black and camouflage with "Army" in big letters across his chest.
The final lap came down to a furious sprint, and Chelimo finished third, snagging the final spot on the team in the 5,000.
His military service had already provided a fast-track to U.S. citizenship. Chelimo and his Kenyan countrymen became citizens after basic training — and in time to compete for this year's Olympic team. Normally, naturalization can take five years or more.
Another Kenyan-born runner in the Army, Shadrack Kipchirchir, 27, qualified in the 10,000 meters (6.2 miles).
"It's not about me. It's all about all the soldiers that sacrificed their lives and dedication and hard work. I'm not going to let them down," he said.
The Kenyan-born athletes in the Army program come from the Rift Valley region, a cradle of champion runners. Kenyans from there have dominated the Olympic medals podium in distance running for decades.
"In Kenya, running is like soccer in Brazil," explained Spc. Leonard Korir, who also qualified for the Olympics in the 10,000 meters.
All together, the Army is sending 11 soldier-athletes to Rio de Janeiro — four runners, a race walker, five marksmen, and one in the modern pentathlon. In addition, two more Army athletes — a swimmer and an archer — have qualified for the Paralympic Games.
"They are great ambassadors for the Army. They represent sacrifice, determination, loyalty, commitment — all of our ethos," said Dan Browne, the coach of the Army's track athletes.
Browne competed in the 10,000 meters and marathon for the U.S. at the 2004 Games in Athens and is now a major in the Oregon National Guard. He stresses that the World Class Athlete Program is open to everyone in the Army who can meet the tough entry standards.
Kenyan-born runners dominate the roster of the Army's World Class Athlete Program for track and field. He says the popularity among Kenyan-American runners has apparently spread through "word-of-mouth."
Browne persuaded his superiors to let some Army runners relocate from their posts to his hometown of Beaverton, Ore. There's no Army base there, but it is home to Nike's world headquarters and a cadre of other professional runners to work out with.
In an increasingly mobile world, a growing number of athletes are leaving their country of birth to compete for another country at the Olympics.
The president of track and field's world governing body IAAF, Sebastian Coe, raised the issue of athletes switching national allegiance during a conference in May.
"I've asked our corporate governance review to look at this, to come back with a set of proposals," Coe said. "In the past, these transfer of allegiance requests have been, sometimes, a little flimsy and we need to address that."
"My instinct is that we need to settle upon a principle that if an athlete starts their international career competing for a particular country, they finish their career for a particular country," Coe added.
The Army says 65 soldier-athletes have competed at the Olympic and Paralympic Games since the World Class Athlete Program was established in 1997. Male and female soldiers competed in everything from target shooting, boxing and wrestling to (paraplegic) sled hockey and cross-country skiing.
The U.S. Air Force has its own program, which includes First Lt. Cale Simmons, who made the U.S. men's team in the pole vault.
The Navy and Marine Corps have not created dedicated detachments to groom elite athletes, but they do grant leave to Olympic hopefuls. The Navy will be represented in Rio by rower Edward King. And David Higgins, an Air Force Academy cadet who plans to become a Marine officer after the Games, will compete in the prone rifle event.
KRCC reporter Holly Pretsky contributed to this report.
SCOTT SIMON, HOST:
The U.S. Army is sending a group of soldiers to the Summer Olympics next month, but they're not to guard the athletes. They're Olympians themselves. Reporter Tom Banse of the Northwest News Network explains why the Army has a unit to groom Olympic athletes, a number of whom only recently became U.S. citizens.
TOM BANSE: Welcome to the U.S. Olympic track and field team trials recently held in Eugene, Ore.
(SOUNDBITE OF U.S. OLYMPIC TRACK AND FIELD TEAM TRIALS)
UNIDENTIFIED ANNOUNCER #1: This here is U.S.A. indoor runner-up at 3,000 meters. From the U.S. Army, Paul Chelimo.
BANSE: We're at the crowded start of the men's 5,000-meter race.
UNIDENTIFIED ANNOUNCER #2: On your marks...
BANSE: The elite runners at the line mostly wear the brightly colored uniforms of their shoe company sponsors, but there's also a pair of slender guys in beige, black and camouflage with the word Army in big letters across their chests.
(SOUNDBITE OF GUNSHOT AND APPLAUSE)
BANSE: After 12 laps, the race comes down to a furious sprint to the finish. U.S. Army soldier Paul Chelimo finishes in the top three to make the Olympic team.
PAUL CHELIMO: I was like, you know what? Let it be what it can be, you know. So I just - I just decided to push.
BANSE: Chelimo was the fourth army runner to make the Olympic team. All four were born and raised and started running in the highlands of Kenya. They got athletic scholarships to American universities. After college, they enlisted in the U.S. Army, which non-citizens with legal residency can do. Chelimo signed up for four years in 2014.
CHELIMO: Actually, my main goal was to represent the United States and being an Olympian is the best way to represent the United States.
BANSE: And so he joined the Army's world class athlete training program.
BANSE: That was the best program because I could - I could do my career as a soldier and also focus on my talent.
BANSE: Military service provides a fast track to U.S. citizenship. Chelimo and his Kenyan countrymen received citizenship after basic training, in time to compete for a slot on this year's U.S. Olympic team. Normally, naturalization can take five years or more. Soldier Shadrack Kipchirchir qualified in the 10,000 meters.
SHADRACK KIPCHIRCHIR: It's not about me. It's all about, like, all the soldiers that sacrificed their lives and, you know, dedication and hard work. I'm not going to let them down.
BANSE: The Army's head coach for track and field is a former Olympian himself and a major in the Oregon National Guard. Dan Browne explains why the Army created a unit where soldiers collect regular pay while focusing on Olympic and Paralympic training.
BANSE: They are great ambassadors for the army. They represent sacrifice, determination, loyalty, commitment - all of our ethos.
BANSE: It was Browne who convinced his superiors to let some of the Army runners relocate from their posts to his home town of Beaverton, Ore. That's far from the nearest Army base, but home to Nike World Headquarters and a cadre of other professional runners to workout with. Kipchirchir says training at the highest level and attending to Army tasks, like making recruiting appearances, is not easy.
KIPCHIRCHIR: You know, like, the Nike athletes - their job is just running. They concentrate on just running. But ours, like - soldiers first. We are soldiers first.
(SOUNDBITE OF U.S. OLYMPIC TRACK AND FIELD TRIALS)
UNIDENTIFIED ANNOUNCER #3: And Chelimo now behind Rupp and Hill and Mead.
BANSE: This year, the Army is sending a total of 11 soldier athletes to the summer games in Brazil. Those are four runners, a race walker, five marksmen and one competitor in modern pentathlon. In addition, two Army athletes qualified for the Paralympic Games for physically disabled athletes. For NPR News, I'm Tom Banse in Eugene Oregon. Transcript provided by NPR, Copyright NPR.