Some 10-year-old children are already showing signs of damage normally seen in adults with bad backs.
Back pain affects 50% of us at some point
Detailed scans of more than 150 Scottish children revealed slight tearing and bulging of the discs that cushion the spinal vertebrae.
None of the children had back pain - and the researchers say the damage may not mean they go on to develop it.
However, with no obvious cause, researchers in Aberdeen suggest that an inherited gene may be to blame.
The link between the type of spinal disc degeneration spotted on these scans and bad backs is by no means certain.
Many adults with damaged discs do not have back pain, although scans on those with problems often reveals damage of this kind.
In the latest study, 154 children from the north east of Scotland were scanned in a magnetic resonance imaging machine, which can clearly pick out different types of tissue in the spinal column.
In 9% of them, or 14 children, clear signs of damage emerged.
Dr Francis Smith, from Woodend Hospital in Aberdeen, told a conference in the US: "We found degenerative changes in the spine much earlier than we ever would have suspected.
"This study revises our thoughts on when we should begin preventive back care.
"Proactive steps should begin early in life, even before puberty."
Approximately half the population will suffer back pain at some point in their lives, and the problem costs the economy and NHS many millions each year.
In the genes
The finding supports other studies which have suggested that genes may be responsible for some cases of spinal degeneration.
Dr Smith went on: "There is no history of poor nutrition, obesity, or any other known disease in these children.
"We suspect there may be genetic causes, although unrecognised trauma in sports or at play could also be a cause."
Dr Tim Spector, a consultant rheumatologist from St Thomas' Hospital in London, said that it was by no means certain that these children would go on to suffer back pain later in life, despite the "damage" to their spines.
However, he told BBC News Online: "In general, it's certain that children aren't doing enough exercise.
"People should be looking at whether their parents or grandparents suffered from back pain, and take action to reduce the risk to themselves if they have a family history."