First the men and women gathered in the gym of the Pentagon took off their prosthetic legs. Then they ditched their wheelchairs for the smooth surface of the floor. Their canes were thrown to the sidelines.

“For all of you that have not played it, it’s a little more complicated than it looks,” Army Sgt. David Hall said Thursday as he stood before his team waiting to take on fellow service members in a game of sitting volleyball.

Hall, a bit of a cheerleader and all-around motivator, soon took on the role of unofficial captain for his 11-member team. And he had never played the game.

About 50 athletes representing the Marine Corps, Army, Navy, Air Force, U.S. Special Operations Command and Department of Veterans Affairs scrambled, dived and scuffed along the court for the third annual Warrior Care sitting volleyball tournament. The program was created to help service members and veterans remain active after injury and illness.

“It just gives the service members confidence,” said Donna Seymour, acting deputy assistant secretary of defense for the Office of Warrior Care Policy. “If they build confidence in the physical arena, they can build confidence in emotional arenas with employment, with education and all kinds of other things that are now different in their lives because of their injury or illness.”

Several of those participating in the tournament had lost legs and arms during the war. Others were battling cancer or working through post-traumatic stress disorder.

Some had never played sitting volleyball — which is played like the traditional sport, except everything from serving to sliding to hitting the ball over a lowered net is done with at least one hip on the floor.

Many found the game harder than they had expected.

“When I was originally asked to play, I thought it was going to be so easy,” said Hall, whose spine and pelvis were injured in Iraq. “I’d come out here and hit the ball back and forth. But now I see it’s actually complicated.”

Hall, who also has PTSD, took over the court, talking to his teammates, who were soldiers and veterans he had never met before. They huddled during time­outs and strategized between plays.

“It’s these team sports that bring us all together,” said Ryan Harshman, 28, a Marine from Hagerstown, Md., who suffered a head injury after an explosion in Iraq.

“You can bring a guy that is 6- foot-5, 300 pounds and he’s completely athletic,” said the staff sergeant. “You get him on the volleyball court and play sitting volleyball, and he’ll get destroyed by a guy with no legs, missing an arm. It builds that confidence — it’s like I’m better than you at something.”

Melissa Garcia, a 27-year-old medic with the Air Force, was diagnosed with breast cancer in January. After surgery, chemotherapy and radiation treatments, the Baltimore native was ready to show her teammates — and her 7-year-old daughter, Isabella — that cancer could not stop her.

“I wasn’t going to let it keep me in the house and down and blue,” she said. “I thought it was very important for her to see that Mommy has cancer, but she can still get up and do everything and stay strong.”

The Marine Corps won the championship — for the third time. But for Marlon Bevans, a retired Navy technician from Norfolk who had to learn how to walk again after a 2010 motorcycle accident, the Marines weren’t the only champions on the court.

“Just being out here, participating, motivating each other, that’s winning to me,” he said. “As long as you get somebody off the bench and make them happy, and show them not to give up hope, that’s winning to me.”