I'm a Light Infantry Soldier who for a living carries heavy loads on my back (120 pound ruck sack, 40 pound machine gun) I am 28 and have been a soldier for seven years. When I say over- train I mean run up to 16 KM in the mourning, swim for an hour at lunch, wieghtlift an hour after lunch and box for two hours a day. I train like this for 5 days a week and weekends off.(Unless I'm in the field or on tour). My back pain seemed to come from nowhere and feels tight all the time. Are weaker abs a reason??. If someone has insight it would be great.