Over 1,000 athletes will take part in Saturday's trail runs and Sunday's mini triathlon event.
But on Sunday, there will be some participants that will be easy to pick out of a crowd.
They will be competing wearing gas masks, cutting their oxygen intake by as much as 20 percent. They are part of Team X-Treme, founded at this event in 2009 by a former Marine looking to pay tribute to his fallen and wounded comrades.
West Point native Jeremy Soles is the founder of Team X-Treme. This year, his team includes Sgt. Johnathan Mozingo, a fellow Marine and Tappahanock native who has served three tours of duty in Iraq and Afghanistan.
Mozingo was wounded during his last tour in Afghanistan and lost part of his left leg below the knee. But that won't keep him from participating in both events this weekend.
"I'm always ready," Mozingo said of his preparation for this weekend. "I've been riding trails in Northern Virginia. There's nothing I can't overcome and that we can't overcome as a team."
Mozingo credits his involvement with Team X-Treme and training for the XTerra event as a huge factor in his physical and mental recovery. He has noticed that getting involved and focused on any athletic event has helped not only him but other wounded veterans as well.
"To have and prepare for a goal and then accomplish it is rewarding" Mozingo said. "Having that to focus on instead of your injuries makes it a lot easier. I tell guys in the hospital all the time: sitting around doing nothing is not going to get you anywhere. You have to set yourself a goal, find an obstacle and get over it.
"It gives the guys hope for something more."
Mozingo is one of six "X-athletes" that will run the 21-kilometer race on Saturday and take part in the 17K bike ride and 7K trail run on Sunday. The events are all part of the XTerra festival which will start early Saturday and Sunday mornings on Brown's Island.