I've come to this realization that my core has let me down (or that I've never really payed attention to my core). To be honest, I've never payed my core it's due -- 20 sit ups were a chore -- always ...
I have started regular strength and core training for the part few weeks after years of no exercise. For the last 2-3 days I notice that I wake up in the night with a back ache that involves muscles ...
I went to defence forces 4 months ago and have had intense training and stuff without no good physical base before. Had to carry a 60 pound bag for miles on my back etc and now having lower back pain ...