The 'Run It Straight' challenge went viral for teen boys. It's already killed one of them.

19-year-old Ryan Satterthwaite loved his mates and playing rugby.

He was polite and kind. Someone who "would do anything for anyone".

He had his whole life ahead of him.

On May 25, Ryan and his friends took part in a viral social media trend, the 'Run It Straight Challenge'. It was the last thing he ever did.

It started off harmless. A fun game to play with friends. Only it had deadly consequences.

Last week, Ryan's family made the devastating decision to switch off his life support after the teenager suffered catastrophic head injuries playing the game.

The rapidly growing social media trend has amassed millions of views. The objective is clear: two players run at each other at speed and collide as hard as they can in a rugby-league-style tackle, aiming to knock the other over. The player left standing is the winner.

Watch a clip of people playing Run It Straight. Post continues below.

The trend is inspired by Australian-based organisation RUNIT Championship League, which describes itself as "the world's fiercest, new collision sport".

"Born to go viral, built to break limits, it has taken social media by storm with tens of millions of views," its website states.

"RUNIT is fast, intense, and raw. It rewards strength and grit. Designed for live crowds and global broadcasts, RUNIT delivers real athletes and the biggest collisions."

It's held events in Australia and New Zealand and says it's a professionally arranged sport, with cash prizes on offer. It's enlisted the help of former NRL heavyweight George Burgess to take it global, with plans to expand to the US, Saudi Arabia and Britain later this year, according to the New Zealand Herald.

Following Ryan's death, RUNIT issued a statement saying it did not encourage any copying of the sport, stressing RUNIT should only be done under "strict conditions".

"This is tragic news, and our hearts go out to the family and friends of Ryan," it said, per Stuff.

"Any contact sport like boxing, martial arts or combat-style activities should only be held in highly controlled environments, which include professional medical supervision and support."

The league said its events screen participants, follow strict guidelines about where and how to tackle, have medical staff on hand and conduct medical assessments before and after the competition.

Ryan suffered serious head injuries playing Run It Straight with friends. Image: Instagram.

Other "Run It Straight" events are being held by another organiser, Run It Straight 24, which RUNIT says it has no affiliation with.

In one video shared by the organiser, a man was knocked unconscious and appeared to suffer a seizure as children watched on.

These types of videos are reaching our young people.

Impressionable kids and teenagers, bored or eager to impress, are turning to this potentially deadly trend for "fun", unaware or ignorant of the potential cost to their lives.

Police, New Zealand Rugby and experts have all come out to raise the alarm about taking part in such a trend.

"It doesn't look like his head has hit anything hard, hasn't hit the ground or his mate's body or head. It's the movement that has caused this injury," Manawatū area commander Inspector Ross Grantham told RNZ's Checkpoint.

"It is that simple, it is that easy to create an injury which can be fatal."

New Zealand Rugby has warned people not to take part. Image: Facebook/New Zealand Rugby.

You only have to look at what we know about contact sports to see the risks involved.

Take soccer, for instance. Studies have found that frequently heading the ball isn't as harmless as it seems. Players who often use their heads to control the ball have shown measurable changes in brain structure, akin to those seen in mild traumatic brain injuries. These changes are linked to declines in verbal learning performance, raising concerns about long-term cognitive effects.

Then there's American football. Studies indicate that a significant number of former players exhibit signs of chronic traumatic encephalopathy (CTE), a degenerative brain disease associated with repeated head impacts.

In fact, one-third of surveyed former NFL players believe they have CTE, highlighting the potential long-term consequences of the sport .

Australia isn't exempt from these concerns.

The Australian Sports Brain Bank has identified cases of CTE in former players of Australian Rules football, rugby league, and rugby union. Notably, the disease can manifest years or even decades after the initial brain injuries, making it a silent threat that emerges long after the final whistle.

The concern about brain injuries has led to stricter rules in sports. In 2021, the AFL introduced the minimum 12-day return to play protocol for players who suffer a concussion, meaning players will miss at least one match. In the NRL, there's a minimum 11-day stand-down period.

Ryan's family want everyone to be aware of the dangers and hope his death can at least serve as a wake-up call.

After seeing reports of "Run It Straight" competitions in New Zealand, Ryan's uncle Peter Satterthwaite knew someone would end up hurt. He never expected it to be his nephew.

"It's just a stupid idea," he told the New Zealand Herald.

"Just don't do it. A little bit of fun has lifelong consequences."

Let's heed their warning.

Mamamia has contacted Run It Straight 24 for comment.

Feature image: Facebook, TikTok/yana_clutch, Facebook.