i don’t see how lying down straight on your back with your arms and legs straight is anything unusual or different? lots of people sleep this way. Personally, I find it near impossible to sleep on my back, however, everynight when i goto sleep i always lie on my back for about 5-10 minutes before laying on my side because it fixes my back up. If I try and just lay on my side straight away i will get small aches all over my back, which is why i always lie on my back for a while first… works wonders 