In college, to make the Ranger Challenge team we had to make a 10k run with full combat load, including m-16 and a 60 lb rucksack. As you finished the run you dropped the rucksack and immediately had to do twelve chins. Our normal PT consisted of calisthenics a 3 mile rucksack run, the chins and electric chairs. We always did PT in combat boots. Three days a week we would follow it up with battalion PT. I dropped from 190 to 172 pounds on a 4k Calorie diet and lost a lot of muscle but I was a machine when it came to strength and endurance.