There was a 20% increase last year in the number of children aged up to 10 treated following violence, according to data from accident and emergency units.
A total of 3,402 children in that age bracket were treated in A&E units after violence in 2010 - up from 2,814 the previous year.
Across the wider population, incidents of violence appear to be declining - down by 37,000 in 2010, but the rise in the number of children being hurt “is a real issue”, researchers said.
Cardiff University professor Jonathan Shepherd said the 20% rise followed an 8% increase the previous year.
He said: “The trend is going on the wrong track. The question is why, but it’s hard to pin down,” he said, adding that recent changes making it more difficult and expensive to take children into care “may be a factor”.
“There may be children left in risky circumstances where they would have been taken into care before,” he said.
The figures, which come before the publication of British Crime Survey statistics later this week, showed an estimated 313,033 people were treated following violence in 2010, 37,000 fewer than in 2009.
The figures from Cardiff University, which collected data from 59 emergency departments and minor injury units in England and Wales, also showed that men aged 18 to 30 were at the highest risk of being injured by violence.
Violence-related hospital visits were most frequent on Saturday and Sunday, and peaked between May and October, the figures showed.
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