FORT LEONARD WOOD, Mo. -- For hours he had walked in darkness, navigating his way through the uneven terrain of the Ozark wilderness. Before dawn, on a crisp late summer morning, Staff Sgt. Chad Hickey and 15 Drill Sergeant of the Year competitors had completed combat readiness exercises, performed drills and marched along rocky trails at the western edge of the Mark Twain National Forest.

The staff sergeant had pushed his body to its limits until he felt weary and exhausted. The day before, he and his competitors had gone 20 hours without sleep, while engaging in fitness exercises and performing drills that could save lives in combat.

As the native of LaGrange, Indiana, sat in the bleachers of Fort Leonard Wood's Gammon Field Sept. 15 awaiting the Drill Sergeant of the Year contest results, he didn't think he had much chance of winning.

When Hickey looked back over the competition last week, he said there were many other worthy competitors. One was Staff Sgt. Sean Jolin, an athletic, decorated drill instructor from Fort Benning, Georgia. Jolin had graduated from the Army's ranger and sniper schools and served three tours in Afghanistan.

Another contestant, Sgt. 1st Class. James Calfa, had deployed in support of Operations Enduring Freedom and Iraqi Freedom as a mortar gunner and radio operator. Corey Irwin, a drill sergeant from Fort Jackson, South Carolina, had experience as an M249 machine gunner, infantry carrier commander and as a sniper section leader.

"Honestly, it was kind of intimidating," said Hickey, a 35-year-old senior drill sergeant at Leonard Wood. "There's a lot of highly-decorated people in there ... a lot of infantry; a lot of combat arms, a lot of people that have more experience in the Army than I do."

After a grueling 12-mile ruck march through the forest Friday morning, the competitors sat side by side at Gammon. Hickey looked at his competition and picked the two he thought would win. He didn't think he was one of them.

Then he heard the announcement on the intercom. Hickey was named the 2017 Drill Sergeant of the Year.

"I was very shocked," said Hickey, a correctional specialist who has been a drill sergeant for 15 months. "There was a lot of great competitors out there this year … I thought I wasn't doing that well in the competition."

Staff Sgt. Bryan Ivery, one of the competition's best athletes, earned Platoon Sergeant of the Year honors and the Tobias C. Meister physical fitness award and placed first among Advanced Individual Training platoon sergeants. Ivery tries to exercise at least twice a day -- once with family and once with his Soldiers. But even he found the physical demands of the contest daunting.

"I think we have stiff competition here. You don't end up here by chance," Ivery said. "It's definitely been trying -- challenging physically and mentally as well."

FORT LEONARD WOOD

Lying in the heart of Missouri's central highlands, Fort Leonard Wood is home to the one of the Army's basic combat training sites, along with the engineer, chemical and military police schools.

The rocky forests that fill much of the installation's 63,000 acres and surrounding woodlands are home to more than 600 animal species.

"I knew how tough the terrain was and I knew the training areas that they have here," said Sgt. 1st Class Brandon Laspe, who represented Leonard Wood in 2016. "You really don't find this much expanse of a base with so many different training areas anywhere in the Army."

Here Soldiers prepare for the most modern forms of warfare, taking updated training courses including operating and rigging recovery vehicles, or adapting to changing Army standards such as the new occupational physical assessment test, or OPAT, added to the Chemical Corps training.

EVOLVING CONTEST

Staff Sgt. Ryan Moldovan said he geared the Drill Sergeant of the Year contest to meet the changing needs and standards of the Army.

"The competition evolves just as the Army evolves," said Moldovan, the 2016 reserve Drill Sergeant of the Year and 2017 planner. "The regulations are constantly changing with the times, with the way our enemies are changing and evolving. And the way we fight is changing and the way we shoot is changing. So we wanted to make sure the competition was completely up to date."

Each of the 16 drill and platoon sergeants had done their part fighting America's wars on hostile battlefronts. Some, like Jolin and Calfa, had battled in combat. Others, such as Staff Sgt. Justine Bottorff, had treated the wounded as a combat medic. They had seen the ugliness of war before they began training Soldiers, as many drill sergeants do.

But in Fort Leonard Wood's rugged woodlands, they faced a different challenge -- an increasingly physical and mental contest, that had evolved from a standard evaluation and PT course in the early 2000s, to a survivor skills and endurance course. Last year's winners, Moldovan and Laspe, spent a year travelling to Army installations across the country, taking notes and watching which drills worked and which needed tinkering.

Among their priorities: create tests that push Soldiers to extreme limits by scheduling contrasting events after each other. Laspe and Moldovan broke up the land navigation course into two parts, one after a round-robin event, and scheduled the other at 2:30 a.m. The contestants, equipped with a compass and a map, had to scour through the night among the brush and pine for predetermined plot points.

"The land navigation course was very challenging and extremely unforgiving," Ivery said. "It chewed us up and spit us out. Some more than others."

"Being able to operate in an exterior environment with unknown circumstances, rapidly changing conditions … and still maintain your composure and execute your mission," Laspe said. "That's what being a Soldier is all about. They proved out there they have what it takes and they are the ones we need training these Soldiers for the best possible Army of the future."

During a surprise land obstacle challenge, the Soldiers again ran through the woods, navigating a winding course while remaining mindful of rocks and hills. The trail posed more challenges than the obstacles given to basic training recruits. After walking tight ropes, climbing over barricades and dodging obstacles, the Soldiers ruck marched to another surprise.

FINAL 'FIGHT HOUSE'

Moldovan called the last event the "fight house," where after complete exhaustion, a competitor must confront an enemy in hand-to-hand combat. Soldiers had to grapple with another Soldier in a base training gym.

"When you have nothing left in the gas tank," Moldovan said, "you still have to be ready to fight and finish the fight, because your battle buddies are relying on you."

The Army created the drill sergeant contest in the 1960s. Through the years, the competition has increasingly built greater standards. Command Sgt. Maj. Blaine Huston of the Army Reserve Command, who competed in the 2002 contest, said this year's class of drill sergeants and platoon sergeants faced greater hurdles from the competition 15 years ago.

"The most physical thing that happened was the APFT," Huston said of his competition. "And now you got drill sergeants out there having to have to hump a ruck down the avenue … They don't know when it's coming. Their mind never gets to shut off. Their bodies never get to fully recover and I don't think they get to fully hydrate."

This year the Army combined the Reserve Drill Sergeant and active-duty Drill Sergeant of the Year categories into one.

BOND AMONG DRILLS

On the contest's third day, as the contestants tackled the Army's new combat readiness test, Staff Sgt. David Shadmani reached the last few reps of the leg tuck exercise. Shadmani, a burly drill sergeant from the Drill Sergeant Academy at Fort Jackson, struggled to pull his knees to his elbows.

"C'mon, one more!" said Staff Sgt. Brittany Barfield, a platoon sergeant from Fort Eustis, Virginia, who stood nearby. "Give it all you got."

Drill sergeants, like many who wear the uniform, share an unspoken bond, Ivery said. During the course of the competition, these drill and platoon sergeants encouraged each other, and gave each other tips. They shared ideas to bring back to share with their home units and Soldiers.

"Just seeing everyone else who's here -- how hard they work, how much they study, the leaders they are," Bottorff said. "Just being around them makes you want to be better."

Hickey said he learned much about where he could improve during the APFT, but his knowledge of battle drills and tactical communication, moving under fire, and other warrior tasks helped him rise to the top of the competition.

"I personally am going to take the lessons I've learned here and take it back to the trainees and my fellow drill sergeants," Hickey said.