Standing just over 5 feet, Army Specialist Karen Arvizu is barely a foot taller than the anti-tank missile she carries in both arms and loads into an armored vehicle. She stands on her tiptoes to wrestle open the 300-pound top hatch.

“I have to step on the seat to get the missile into the launcher,” said Arvizu, 24, a soldier from Los Angeles. “It’s half my body weight.”

Arvizu typically drives Humvees or transport trucks at Fort Stewart in Georgia, but for the past three weeks, she and 59 other women soldiers have been getting a taste of what it takes to serve in combat.

By spending their days lifting 65-pound missiles and .50-caliber machine guns, all while wearing 70 pounds of body armor, they’re helping make history as part of an Army study that will determine how all soldiers — including women, for the first time — will be deemed fit to join the front lines.

The Pentagon ordered last year that women must have the same opportunities to serve in combat jobs as men, with thousands of positions slated to open to both genders in 2016. An Army survey shows only a small fraction of women say they want to move into combat jobs, it also revealed soldiers from both genders are nervous about the change.

With roughly one in five Army positions considered combat-related, commanders are turning to science to find a unisex standard to judge which soldiers physically have the right stuff to fight wars.

Focus is on battlefield tasks

Testing at Fort Stewart and other U.S. bases is breaking away from the Army’s longtime standards for physical fitness — pushups, situps and 2-mile runs — to focus instead on battlefield tasks, such as dragging a wounded comrade to safety or installing the heavy barrel of the gun mounted on Bradley vehicles.

David Brinkley, deputy chief of staff for operations at the Army’s Training and Doctrine Command at Fort Eustis in Virginia, said some people think the Army is coming up with unrealistic requirements while others believe standards will be lower to let women fight on the front lines. “We intend to do neither. That’s why we based this on the actual thing you have to do,” he said.

At Fort Stewart, a volunteer group of soldiers — 100 men and 60 women — are spending a month drilling on the most physically challenging tasks demanded of infantrymen, cavalry scouts, mortar launchers and tank crews. In March, scientists from the Army’s Research Institute for Environmental Medicine will have the troops perform those tasks while wearing heart rate monitors, masks that monitor oxygen intake and other equipment.

One of the volunteers, Specialist Artrice Scott, said she has no intention of trading in her job as an Army cook to join an infantry platoon or an armor unit. But she sees the testing as a great opportunity to lead the way for women.

“The heaviest thing we lift in the kitchen is boxes of frozen chicken, 45 pounds,” said Scott, 29, of Mobile, Ala. “And you don’t have to lift those over your head.”

During a training session, Scott shaved 45 seconds off her previous best time carrying two anti-tank missiles into a Bradley armored vehicle and loading them into the turret. Army commanders say there are no doubts that women have the mental and technical abilities needed. Only their ability to perform the most arduous tasks has been questioned.

Nagging stereotypes persist

The survey released Tuesday found there were nagging stereotypes. Male soldiers fretted that their unit’s readiness will be degraded because of pregnancy and menstrual cycles. Or they worried that women incapable of the physical demands still would be brought in.

However, the survey also showed that only about 8 percent of Army women said they wanted combat jobs.

Maj. Gen. Mike Murray, commanding general at Fort Stewart, watched as coed groups set up heavy mortars on a practice field. Murray said it’s time to open combat jobs to women and “this is going to get studied to death” so the Army can prove to naysayers that women soldiers are physically capable.

The volunteers at Fort Stewart include a mix of combat veterans and newcomers, but it didn’t take long for the group to jell.

“It was almost like a high school dance where you had the guys over here and the girls over there,” Murray said. “A week later, it was amazing how fast teams form.”

Exactly what sort of fitness tests or standards will come out of the Army’s study remains to be seen. There are no current fitness requirements for serving in combat beyond the Army’s standard physical fitness test for all soldiers, which grades men and women on different scales.

Arvizu said she found the heavy lifting humbling. And though she felt encouraged by her male colleagues, she had no desire to give up driving a truck and join a combat unit. “It’s not that I came, I saw and conquered,” she said. “But I came, I saw and I did my best.”