As America was sending its sons and daughters into battle a decade ago, the U.S. Army’s expertise was based largely on the conventional philosophy of tank versus tank, foot soldier against foot soldier.

That changed in a flash. The invasion of Iraq’s capital of Baghdad, led by Fort Benning’s 3rd Brigade Heavy Combat Team, would give way to years of war fought often in smaller towns and cities.

Shadowy terrorist figures — mixing in at times with locals — replaced the uniformed Warsaw Pact adversaries the military had long trained to fight against in a major conflict. Improvised explosive devices (IEDs), or homemade bombs planted on roadways or worn by suicidal individuals, quickly became a deadly threat aimed at not only killing U.S. soldiers, but keeping them on edge and wounding morale.

The Army knew it had to adapt — and fast — with its ranks swelling with civilians-turned-soldiers, many of whom were deploying within 90 days of completing their basic and advanced combat training.

Naturally, those changes rippled swiftly to the Home of the Infantry at Fort Benning, changes that are entrenched in the way recruits are taught today.

Staff Sgt. Jesse Murray, who entered the military just before the U.S. invasion of Iraq in 2003, knows the lessons learned from Iraq — and subsequently from Afghanistan — as well as anyone. The Fort Benning Drill Sergeant of the Year deployed to Iraq three times and today is among those training troops how to survive in harm’s way.

“When I was a private, a lot of my squad leaders and leadership did not have any combat experience. And I remember during my first deployment to Iraq, there was a certain kind of anxiety,” said Murray, who was with the 2nd Infantry Division at Fort Lewis, Wash., when the Stryker — a speedy armored vehicle and troop carrier — made its appearance in Iraq.

Contrast that to today, when virtually all of the drill sergeants Murray works with have seen action in either Iraq and Afghanistan and have their combat infantryman’s badge.

Specifically, Murray said, one station unit training — which combines basic and advanced combat training into one continuous stream of instruction — shifted away from trench warfare and firing rifles from foxholes to using various shooting positions from barriers and around building corners.

Less emphasis was placed on the use of nuclear, biological and chemical masks, with more time spent using night-vision goggles and devices. The term “weapons immersion” also entered the Army’s terminology.

“When I went through originally, the only time we touched our weapons is when we went out to the range,” the drill sergeant said. “Now it’s a constant thing. Privates have their weapons on them all the time, and that reflects what they’re going to see in Iraq ... A lot of times they try to overrun the bases and we don’t have time to run back to our rooms, grab all of our ammo, get suited up, and run back out to wherever we need to be.”

Training on improvised explosion devices also ramped up and easily grabbed the attention of recruits, particularly with news stories from the warfront detailing how a mundane foot patrol or drive from one area to another ended up with soldiers losing an arm or a leg, and for some, their lives.

“Whenever we talk about IEDs, that’s generally when I’ll talk about the real-life effects where soldiers that I know have gotten hurt or injured permanently,” Murray said. “When we talk about (rocket-propelled grenades), I have a story that specifically relates to that. What I think it does is help make it real to them ... They do soak that up because it’s something that they know absolutely nothing about.”