FORT JACKSON, SC — More sedentary recruits prompted the Army to update basic training for the first time in 30 years.

About 27 percent of young people in the United States are too overweight to join the military, according to a report released late last year by Mission: Readiness, a nonprofit organization of 89 senior retired military leaders. The report also found that nearly 15,000 potential recruits fail the military's physical fitness entrance exam every year because they are too fat.

To prevent injuries during basic training, the Army will gradually increase soldiers' fitness levels so they'll be ready for more rigorous training later.

“We are seeing more stress fractures, a greater body fat percentage and a decline in the ability of many new soldiers to perform one minute of push-ups, one minute of sit-ups and make a one-mile run,” Lt. Gen. Mark Hertling, Training and Doctrine Command's deputy commanding general for Initial Military Training (IMT), said at the Army's recent IMT forum.

Army statistics show that 16 percent of soldiers are non-deployable this year, mainly because of health problems. Defense Department records also show that between 2006 and 2008, bad backs, strained knees and other ailments increased from 1.4 million cases in the overall military to 1.9 million.

Stress fractures and other serious injuries are partially responsible for a rise in the attrition rate for new recruits, which is between 10 percent and 15 percent, according to the Army.

Additional calisthenics to build core body strength, agility and strength will be a part of the new standardized basic training regimen, Frank Palkoska, head of the Army's Fitness School at Fort Jackson, SC, told the Associated Press.

The new 10-week basic training system is expected to be in place by July. Additional focus also will be on marksmanship.