It will take six months before Nick Ashill is able to walk again.

Left for dead on a remote US highway, Kiwi ultra-runner Nick Ashill​ looked down at his body "smashed up with bones sticking out" and cried out for help.

Despite being on a different continent, his wife Sarah was the first to respond - he could hear her voice coming from the phone which had been thrown from his backpack after a pick-up truck had deliberately run him down.

Nick was running across the US for charity on August 2, and while on a call to his wife and daughters on holiday in Cyprus, he noticed a dark-coloured ute hurtling straight towards him.

"There was no wobbling or deviation from the white line of the shoulder," said Nick. "This individual knew what they were doing, and I really struggle with that when play it through my mind."

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As he realised the ute was gunning directly for him, he tried to throw himself over a small fence but the ute struck him, throwing him high into the air.

SUPPLIED The impact left Nick with severe injuries - including a smashed pelvis, compound fracture to his right femur and bowel perforation.

The 53-year-old landed in a ditch, his right leg and pelvis taking the full impact of his fall. "I remember looking at my leg and it was smashed up with bones sticking out," he said.

"Although my phone was thrown from my pack, it was still on and I heard Sarah."

He had run a massive 3949km in 81 days to raise money for pulmonary fibrosis, and was only 922km from the finish line.

His wife and two youngest daughters were due to join him and their eldest daughter Emily - who was part of his support crew - in New York to watch him complete his goal of 5400km.

They would often talk hands-free on Skype while he was running - his phone strapped to his Camel backpack so his family could see what was around him.

As the horror unfolded that morning Sarah could only see grass as the phone rolled along the ground.

ABC6/SCREENGRAB Sarah Ashill is asking for the motorist who hit her husband to turn themselves in.

"I just somehow clicked into gear while the two children standing beside me were hysterical," said Sarah.

"I tried to work out where the blood was coming from, and I actually said to him 'I'm concerned you're going to bleed out while you are talking to me so lets deal with it'."

Nick can remember Sarah asking him questions which kept him conscious through the intense pain.

SUPPLIED Nick and Sarah are keen runners, seen here on the 50km Eco Trail in Paris.

"But after a time the pain left and I felt very, very tranquil, I think I was starting to lose consciousness," Nick said.

"Then I realised that I have got to get out of this ditch. There's nobody to help me and I need to get on the road so I'm visible."

But as he tried to move his hopes were quickly dashed. "I realised my pelvis was completely smashed so I couldn't lift myself up," he said from his hospital bed in the US.

SUPPLIED Nick and Sarah (right) with their four daughters before he embarked on the mammoth charity run across the US.

"I just lay there and I can recall crying for help again. It felt like within a couple of minutes I heard the voices and footsteps of the local patrol guys.

"That was an incredible feeling, knowing that I had been found. It's hard to describe."

The couple, originally from Wellington, are adamant had they not been on the phone, it would have been a different outcome.

It was the combined efforts of Sarah and daughter Emily who between them liaised with local troopers to track down his location.

"I think the one question that saved him was when we asked 'have you seen any aeroplanes today?', he said no."

That meant the troopers could figure out where was in relation to where he started, she said.

"My call cut out at 46 minutes, and they found him five or six minutes after that."

It took Sarah 35 hours on four connecting flights to reach Nick at the hospital in Columbus, Ohio.

"He was in critical condition when I left. I think some people go to pieces in a crisis and some people get cold and collected, and I'm one of them - then fall apart afterwards," she said.

That moment came for Sarah weeks later after doctors found an infection in Nick's left leg which had spread to his scrotum and belly.

"When they rushed him to surgery I didn't know what they were going to find when they opened him up," said Sarah who trained as a nurse in the emergency service response unit.

"That really got me knowing that I might lose him all over again. I locked myself in one of the bathrooms at the hospital and rang my girlfriend in Golden Bay, and balled my eyes out to her."

Through an "amazing level of expertise" the surgeons managed to put Nick back together, and he will be joined by his two youngest daughters on Sunday.

Despite being in hospital for a month their insurance company has yet to confirm if it will cover the costs, which have already escalated to over $500,000.

It will take six months before Nick is able to walk again, and will require intensive rehab. The family currently live in Sharjah in the United Arab Emirates, but they are yet to decide where they will be based next.

"Not knowing whether we were going to be covered and have some money, or whether we are going to be struggling for the rest of our lives is really hard," said Sarah.

"We will have a family conference once everyone is here - it's going to change our lives for now."

A relative has set up a Give a Little page to raise money for Nick's ongoing treatment.

Police are yet to arrest anyone in relation to the hit and run, but have told the family they believe the vehicle involved was a 1992 to 1998 dark-coloured Chevrolet or GMC ute.

"What's hard for me right now is knowing this jerk is still out there on the road, and I wonder if it's happened before," said Nick.

"I play it through my mind every day. I'm here because of Sarah, the credit has to go to her, she was amazing."