The Army has a new physical training plan for its 145,000 recruits this year, and planners hope it will tackle one of the military’s most pressing modern problems: Recruits are overweight and out of shape. The most common reason a potential recruit is rejected is his or her weight, but even the recruits who aren’t too heavy usually arrive at basic training with less endurance and strength than in years past. So, many are injured as they try to meet Army fitness standards, including stress fractures from not having done enough weight-bearing exercise or eaten enough calcium and iron. The new regime is meant to counteract that: more stretching, more exercise for the abdomen and back, more balance training. Sit-ups have nearly disappeared, as have long runs. The new exercises are similar to Pilates and yoga, and are more related to the tasks soldiers will have to do on the battlefield.