Health professionals have voiced concerns as the Runit Championship League makes its debut in Auckland.
The controversial new combat sport has players running full force at each other.
Stacey Mowbray, Headway CEO, says this sport presents high risks of brain injury - and the research agrees.
"One thing that worries us is - have these people been fully informed? Listening to people involved in it, they didn't actually seem to realise there was a difference...we want to educate people."
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