"I like the way you're working with her today," an instructor told McKinnon.
"Yeah, she's calm today," McKinnon said.
And McKinnon looks pretty relaxed when riding her horse, named Minnie.
"Minnie and I have been working on this for a long time," McKinnon said.
It was Minnie who lifted McKinnon out of the depression she fell into after she was wounded.
People at Walter Reed say the first time they ever saw her smile was on this horse.
"I'm an animal lover at heart," McKinnon said.
Spc. John Thomas, one of the ceremonial guards who walks with the fallen, now walks with McKinnon.
"When they come here, they're hurt and you get to help them rebuild themselves," Thomas said. "It makes it a little better, instead of just doing funerals all day and seeing the worst side of the war, you can see the better side of things."
Nick Paupore had never been around horses.
"I wasn't sure, and they talked me into coming," Paupore said.
He never expected Wylie's steady gait would help him learn to walk again.
"It's really hard because your mind is thinking you don't have that leg and so your mechanics are all screwed up and so when you sit on a horse it kinda re-teaches your mind how to walk again," Paupore said.
But the body still has to do the work.
"I want you to think about stretching up through the abdominal area and through the rib cage and lifting everything up," an instructor said.
"It's a great exercise because you gotta hold your core muscles together," Paupore said.
And much to his surprise it turned out to be fun.
"I never thought I'd like riding horses, but it's a wonderful feeling, like every little boy wants to be a cowboy," Paupore said. "I had to do it the long and hard way."
The horses of Arlington: they lend dignity to the final journey of the dead, and hope for the wounded on the road back.