FORT JACKSON, S.C. | At 5 a.m. on the Army's largest training base, soldiers grunt through the kinds of stretches, body twists and bent-leg raises that might be seen in an "ab blaster" class at a suburban gym.
Adapting to battlefield experience in Afghanistan and Iraq, the Army is revamping its basic training regimen for the first time in three decades by nixing five-mile runs and bayonet drills in favor of zigzag sprints and honing core muscles.
Trainers hope the switch will better prepare soldiers physically for the pace of combat, with its sudden dashes and rolling gunbattles. They also want to toughen recruits who are often more familiar with Facebook than fistfights.
The exercises are part of the first major overhaul in Army basic fitness training since men and women began training together in 1980, said Frank Palkoska, head of the Army's Fitness School at Fort Jackson, which has worked several years on overhauling the service's fitness regime.
The new plan is being expanded this month at the Army's four other basic training installations — Fort Leonard Wood, Mo.; Fort Sill, Okla.; Fort Benning, Ga.; and Fort Knox, Ky.
"We don't run five miles in combat, but you run across the street every day," Mr. Palkoska said, adding, "I'm not training long-distance runners. I'm training warriors" who must shuttle back and forth across a back alley.
Drill sergeants with combat experience in the current wars are credited with urging the Army to change training, in particular to build up core muscle strength to walk patrols with heavy packs and body armor or to haul a buddy out of a burning vehicle.
One of those experienced drill sergeants is 1st Sgt. Michael Todd, a veteran of seven deployments to Iraq and Afghanistan.
On a recent training day Sgt. Todd was spinning recruits around to give them the feel of rolling out of a tumbled Humvee. Then he tossed on the ground pugil sticks made of plastic pipe and foam, forcing trainees to crawl for their weapons before they pounded away on each other.
"They have to understand hand-to-hand combat, to use something other than their weapon, a piece of wood, a knife, anything they can pick up," Sgt. Todd said.
