'JUST a cycle, followed by a run, then a paddle, with another wee cycle to finish," says Greg McEwan, reciting the quote emblazoned across the home page of the Epic 2012 website with some deliberation.

Breaking a challenge into more palatable segments is an established psychological practice and, after half an hour discussing details, it is only understandable that the 30-year-old requires recourse for reassurance. After all, what he and two friends have planned for this June goes beyond understood physical capabilities.

The scale of what McEwan, Garry Mackay and Lee Peyton are proposing is such that distances and times involved almost lose meaning, but let us borrow their own coping mechanism and consider the component parts.

Beginning at Gallie Craig – the southern point of the Rhins of Galloway peninsula – on June 17, the trio will cycle the 120 miles to Milngavie, before running 13 miles of the West Highland Way and hopefully arriving in Drymen as night falls. In itself, an epic undertaking and one worthy of praise, a pint and a few days rest. Not for these boys, though. The following morning, they will rise early to run a minimum of 53-miles north along the famous trail, the aim being to leave no more than 30 miles of the route remaining to complete the day after. Again, well done, above and beyond, we'd have sponsored you for just the first day etc etc.

But hang on. Day three will not be finished until the intrepid trio have climbed Ben Nevis and returned to their Fort William base for some food and a few hours' sleep ahead of two days' kayaking the 60-odd mile stretch of Loch Ness through the Great Glen to Inverness. "Once we get there, my mind tells me it's job done," says McEwan, pausing briefly to enjoy the moment before being disturbed by the reality of the 130-mile, final-day cycle on exposed roads from the Highland capital to the finishing line at John O'Groats.

So, just a normal six-day, boys' holiday then? "Well, I've got a day off before I need to come back to work," says McEwan, who works in marketing and also manages GB 400m runner Eilidh Child. "Actually, even thinking about it I get excited and on the first and last day I reckon I'll be like a kid in a sweet shop."

That exuberance will be tempered not only by the reality of the challenge but also the motivation behind it. Mackay and Peyton are experienced endurance event competitors, having won the 100-mile Yukon Arctic Ultra race together, but McEwan's background is in 800m running, and it was the death of his grandfather that moved him to try something different.

A Land's End to John O'Groats run was disregarded on the grounds that it would be too monotonous before the current plan began to crystallise and, with it, the notion to raise the £60,000 required by Yorkhill Children's Foundation to purchase equipment used to help knit bones back together after serious trauma injuries. "We could have just said we were going to raise money and handed it in but we wanted it to be for something specific," explains McEwan, who has previously run half marathons to raise money for the hospital and will run the Berlin event in September. "We didn't want it to be a fresh coat of paint in a reception; we wanted it to mean something to people, to the families of these kids."

The exiled Fifer speaks as someone who has experienced the anguish that those relatives experience. As he stands on the start line, McEwan will allow himself a moment to reminisce. "When I was 11 or 12 I lost my cousin John, who was like a brother to me," he explains. "He had a heart illness, went down to Newcastle for an operation and didn't pull through and I've never felt my world fall to bits like that. I carry it with me every day because I wear a ring with his initials and date of birth on it and it would actually be his birthday the day after we start. I'm doing all this for him, too."

That tribute brings clarity of purpose whenever the 20-mile training runs hurt, whenever the welter of logistical considerations clouds his consciousness, whenever he worries that one kayaking session is not enough, whenever his attention is diverted by the gala dinner the trio will host on June 30. So too, though, does the fear of letting down his colleagues, a pair of firefighters inured to difficult circumstances.

Rather than be cowed, though, McEwan is using those concerns to his advantage. "The numbers have lost meaning for me now," he says, explaining how he has had to unlearn all he knows about running and slow himself down to four or five mph. "The first thing I did was scare myself because I needed my body to hurt so, one morning early on, I drove to Milngavie and ran the 25 miles to Drymen and back off road. I was far too quick and it was sore but I knew then that my body could handle it, but if I look at the numbers, they do scare me."

The physical challenge has become a psychological struggle. Just as well McEwan has his mantra to fall back on.

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