Manawatū Area Commander Inspector Ross Grantham said Satterthwaite suffered a serious head injury when tackled, and was taken to hospital by his friends.

“The tackle game played by the group of friends was based on a social media-driven trend, where participants compete in full-contact collisions without protective gear. While this was an impromptu game among friends, not a planned event, this tragic outcome does highlight the inherent safety concerns with such an activity.”

Grantham said police urged anyone thinking about taking part in a game or event like this to “consider the significant safety and injury risks”.

“While this is not a criminal matter, Police will continue to undertake enquiries on behalf of the Coroner,” he said.

Police Commissioner Richard Chambers told reporters on Tuesday afternoon that Satterthwaite’s death was “a huge tragedy”.

“A young man lost his life as a result of participating in what I understand to be a social media frenzy,” he said.

Chambers said police would work to understand what happened, and stressed that police discourage any activity that could result in harm.

The run it straight game originated overseas, through the Australian-based RUNIT Championship League competition.

The competition is built around actions seen in rugby union, rugby league, the NFL and AFL. Opposing individuals – a ball runner and a tackler – stand at each end of a 20m x 4m field, and run full speed at each other with the goal of trying to bowl each other over.