There was a study (1) done in 2016 comparing 30 road cyclists with 30 mountain bikers and 30 non-cyclists. The cyclists in both groups had been cycling for 6 years and were of similar age and experience.
The road cyclists showed significantly greater thoracic kyphosis and trunk inclination than did the mountain bikers and non-cyclists in a standing posture.
This is the normal standing posture of the spine
On a road bike, the cycling posture was characterised by greater lumbar flexion and…