At 7pm next Saturday a group of Glasgow Warriors players will sit in the dressing room in Dublin's RBS ground and gird themselves for the second half of their RaboDirect PRO12 final against Leinster.

At exactly the same moment, Hefin O'Hare will embark on a rather more strenuous challenge.

For while the Warriors will have 40 minutes of pain and effort to look forward to, their former winger will be contemplating the 24 hours he is set to spend on the West Highland Way, running the equivalent of four marathons in a bid to raise money for the Yorkhill Children's Hospital. If all goes well for the Glasgow boys, their endeavours will end in glory; if he still has the stamina, O'Hare might just treat himself to a pint in Fort William.

O'Hare spent six years on Glasgow's books, a period that came to an end two seasons ago. Since then, he has established himself in his second career as a building surveyor while also turning out on the wing for GHA, but his appetite for bigger challenges had already found expression in the Lands End to John O' Groats cycle ride he undertook - also for Yorkhill - a few years ago.

"When I did the bike ride it was great to be able to give the money to those guys," O'Hare, now 34, explained. "It's really good to be able to give something back to people who can't help themselves. I've got two children of my own, and it's really humbling to go in and see those kids at Yorkhill. What they are going through can be really tough, so it's nice to be able to do something that helps them even just a bit."

O'Hare, who represented Wales at rugby league and also played for the Scotland sevens side, might have been improbably slight for a modern rugby winger, but that more diminutive frame will be a blessing as he slogs through the night along the banks of Loch Lomond to Rannoch Moor, Glencoe and beyond. Yet it also served him pretty well for the Warriors in his professional playing days, never more dramatically than in March 2010 when he scored a dazzling solo try against Leinster at the RDS, one of the most spectacular individual scores the Celtic competition has ever seen.

If inspiration is required, Warriors coach Gregor Townsend could do worse than replay that footage to his players in the build-up to Saturday's game. O'Hare's own focus will be on getting his preparations right for an adventure he will undertake in the company of friends Steven Porteus and Rangi Jercevich.

Porteus is a sub-3hr marathon runner, and O'Hare jokes that his biggest fear is that he won't be able to keep up. For his part, Jericevich, like O'Hare, is more usually spotted on the wing at Braidholm than on Scotland's best known long-distance footpath. "They are both fit lads," O'Hare explained. "They's nice guys, too, so it will be good to do it together.

"It's quite hard to train for something like this. What do you do? You don't go out and run 100 miles every day. I just try to keep my legs ticking over by going out for eight-mile runs, 10-mile runs and cycling to work, which is 20 miles. I've just been trying to build up my endurance.

"There is nothing that is going to stop you hurting on the day. It is just about trying to mitigate that and make it the smallest amount of pain you can get, so I've been trying to run every day and keep myself as fit as I possibly can by doing a variety of different exercises."

It is not quite a step into the unknown, as O'Hare has already cycled the length of the West Highland Way. Or rather, he cycled as much as he could. "There were seven of us doing it and we had to carry the bikes for about 20 miles," he recalled. "You can't cycle the whole way, and there was a lot of pushing, especially on the east side of Loch Lomond.

"We actually went up the Devils staircase at about 10 o'clock at night, coming up to pitch-black, and went down the other side with head torches on. This time, we are planning to set off at about seven o'clock. The idea is to get the night part out of the way while we are still quite fresh, and then we will do the majority of it during the day."

Major food stops are planned at Tyndrum and the Kings House Hotel, but beyond that they will only eat what they can carry.

Yet, as he pounds out the 96 miles of the Way, O'Hare admits that part of him will be in Dublin with his old team-mates. "I had some great years at Glasgow and made some great friends," he said. "I'll be thinking of the lads, Al Kellock and all the rest of the boys. We got to the semi-finals while I was there, but it's wonderful that they've now gone one better.

"They lost to Leinster in the semi last year, so I think they feel they have something to prove. I think they can do it. I really think that this is going to be their year."

n Donations in recognition of Hefin O'Hare's West Highland Way run can be made online at: