I have heard this before and it makes sense but I do think babies have the ability to communicate whether they are comfortable or not which is what I try to follow. I would like to read more about the exact differences between how the body is supported when on back compared to front, there are babies that seem very comfortable on their front so that sparks my curiosity about how it was determined that back was the right way! Currently DD2 usually begins sleeping on her back but through the night seems to complain till she settles quickly on her tummy, I know I get uncomfortable staying in the same position for extended periods so this is why I have tried to follow her cues on how she would like to be but am very keen to understand better how this might be inaccurate logic on my part. DD2 (and DD1 back when she was little) doesn't spend much time out of my arms whilst awake so am also wondering how this might relate to baby wearing/carrying? What would be the most 'natural' position in that sort of environment? What about the incline in carseats?

It is very interesting although I will continue to listen to my baby and the instinct from that, I am motivated to read some more. Both my babies have had what I consider abnormal head strength straight from the womb (no wobbly head, it is almost creepy) so that might be influencing my thoughts somewhat. DD2 especially is just a very big and strong baby, she has been rolling for a while so the tummy time thing is a bit mute for us now but would still love to know more. I would never keep a baby in a position they were actively protesting and don't think tummy time should be 'forced'.