New research on concussions has shed light on how rugby head collisions affect community players.
The collaborative study includes research by Otago University and data from local and international rugby governing bodies.
It used smart mouthguard technology - obligatory in training and elite matches from next year.
Research scientist Janelle Romanchuk says it measured 17,000 incidents across 300 players.
"86 percent of that data would be relative to what you might experience jumping on a trampoline or what you might experience on a roller coaster."
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