1. Equip your soldier with a medium size bag, like a kitbag, and load it to the half.
2. Equip the soldier with a medium weight wepon such as 5.56mm MX or Katiba.
3. Equip the soldier with a medium weight vest, load it to the half. Also get a helmet.
4. Now try to sprint more than 10-15 seconds. Soldier is extremely fatigued, and you will be just able to walk so slow, almost like pressing the W+S walk mode. Gaining stamina is almost impossible if you need to move