A friend of mine thinks the spine should either be very slightly curved or not curved at all with a good posture. He showed me military posture which seems to show that’s the case, however all the “normal” posture things I’ve seen show the spine is more naturally curved.
So my question is the military posture the correct one and should our spines be mostly straight or no? If not any evidence for this so I can show them?
No. The cervical and lumbar spines are curved in (lordosis) and the thoracic spine is curved out (kyphosis.) Straightening of these as seen on x-ray is a sign of severe muscle spasm.