i stretch on the floor and it feels good but as soon as i get up my core feels stricken. i used to haul boxes of books from the basement of the brown elephant on a luggage carrier several blocks to my apartment in ukrainian village and then haul them up three flights to sort and then haul them back to myopic books to sell. at the same time i hauled heavy photo equipment the same way. finally i got a hernia and stopped everything. that being said i know i've slouched a lot and spent too much time reading in bed. my side is sunken from continuous occupation. there's a lesson in all this: use your head, not just for reading.