I know that the lower back loses stability when stretched out, i.e. sitting in poor posture, but is the same true for the rhimboids/lower traps? I'll slouch in my seat at school while reading/etc. so as to not get super close to whatever I'm reading and stretch out my lower back, but my last workout, when I would feel my upper back tight, it looked arched/in flexion. Should I just do supermans to be sure? Should I not stretch my hips at all with a rounded back (hard to do)? Should I just sit up straight all day (hard to break the habit)?