New York (CNN) -- Wounded warriors will gear up Sunday and go into a different battleground -- the New York City Marathon.
Twenty-five disabled veterans will push through 26.2-mile route through the five boroughs, running, churning hand cranks, pushing wheelchairs and propelling prosthetic legs to the finish line in Central Park.
One of those 25 was in Walter Reed Army Medical Center three years ago, suffering from a lost limb, a reverse colostomy and two collapsed lungs that made it near impossible to breathe.
"I never thought I'd ever be able to run, let alone run a marathon, which was always a life goal for me," Michael Kacer said.
On Sunday, Kacer will be running in his 10th since 2009. He is a member of the Achilles Freedom Team, a group of wounded veterans, most of whom are motivated amputees and victims of traumatic brain injuries, who race in marathons across America.
Kacer, 29, who served in the Pennsylvania Army National Guard, will tell you in June 2008 he "got caught cheating at spades." Just as fellow army comrades caught Kacer hoarding his last heart card in a ritual game of spades, a rocket pierced his combat outpost in Zerok, Afghanistan.
He lost his left arm in the explosion.
"I'd love to, I'd love to, I'd love to, but I can't," Kacer recalled saying in labored breaths to Freedom Team recruiters at Walter Reed back in 2008.
Today, Kacer puts up the same fight he did on the battlefield.
"As long as you find that something that drives you, in my case it was running ... all that self-doubt slowly melts away," he said.
Kacer gained an extra measure of fame in June for for leaning over a rail and making a one-handed catch, with his hat, of a foul ball in Yankee Stadium.
"As soon as I saw the ball in my hat I thought, I have to make this look as nonchalant as possible," he told CNN. He gave the ball to his 13-year-old nephew, whom he had brought to the game as a surprise, during the weekend of Achilles' annual Hopes and Possibilities 5-mile run.
On Friday, a wisecracking Kacer greeted a bus full of suited-up athletes, patients of Walter Reed and their families. They were escorted through Manhattan by the "Nam Knights," a brigade of Vietnam and some Iraq vets on motorcycles who shepherd wounded warriors on their travels across the United States.
Joining Kacer on Sunday will be good friend and former patient Nick Koulchar.
A combat engineer with the Army's 1st Armored Division, Koulchar lost both his legs in a roadside bomb in Sadr City, Iraq, in August 2008.
He flashed an oversized flag tattoo on his right forearm, as he told CNN he was looking forward to an enjoyable weekend with good people, and getting 26.2 miles of New York City to himself.
"We get to see sights and places sometimes empty. Other people don't get to see it like this. It's peaceful."
This will be Koulchar's sixth marathon on hand crank, his first in NYC. The goal is to finish on the hand cycle in under two hours.
"Everyone takes there own path in life after Walter Reed, just as everybody had a different path before they came together there."
On the Freedom Team, former soldiers and patients reunite to take the path together again.
For Kacer and Koulchar, it's a "family reunion."
The Achilles International Track Club -- the name is an allusion of the Greek hero whose single weakness was his vulnerable heel -- was founded by Dick Traum in 1983. Traum in 1975 had become the first amputee to compete in the New York City marathon, at the age of 35.
In 2004, Traum paid a visit to WRAMC and asked veterans, recent amputees some three or four weeks out of Iraq, if they were going to do the NYC Marathon.
"Those kids looked at me like I was crazy," he said.
Since then, the Achilles Freedom Team has sponsored more than 1,000 veterans in various marathons, director Genna Griffith told CNN. She accompanies a recruitment team to the army hospital once a month to teach hand-crank clinics.
The hand crank, a low-to-the-ground, three-wheeled machine that operates like a bicycle pedaled by hand, is used by most vets on the Freedom Team.
Not everyone will, however. This year, Melissa Stockwell, the first female amputee from Operation Iraqi Freedom, will become the first female amputee on the team to attempt the NYC Marathon running on her prosthetic leg.
There are more than 1.4 million Iraq and Afghanistan veterans, according to Jo Schuda at the Department of Veteran Affairs. Since the war in Afghanistan began in October 2001, more than 46,957 have been wounded there and in Iraq, said Isabel Black, press secretary for the Iraq and Afghanistan Veterans of America. Of those service members, 843 Army soldiers alone have had major amputations, according to the Army Surgeon General.
Kacer said that for amputees coming home from the battlefield, "the biggest hurdle to overcome is believing it's not over, it's just a new beginning."
"Adapt, and overcome," he advised.
For Koulchar it's developing the patience to learn how to be independent again. Although relying on a wheelchair for everyday living is taxing on his chest and arms, he said he will keep doing marathons until his body tells him to stop.
"I don't know how many I have left in me," he said, "but I'll do them as long as I can stay healthy."
These men take solace in sharing battle stories. Not all wounds are surface deep.
"It's the unseen battle scars and injuries that take a bigger toll than what's there in the blatant open," said Kacer.
Kacer said he runs two races.
"The first is for me," he said. "When I'm finished, I go back out, find the last soldier on our team, and I bring him in."
CNN's Rod Griola contributed to this report.