6000D SPELHER Glacier Olivier Allamand

The ski resort of La Plagne sits 2,000m high in the French Alps, just a medal-winning ski-jump from Albertville, home of the 1992 Winter Olympics. In fact, from the highest village on the hill, you can see the Olympic bobsled course twisting its way down the mountain.

As MR arrives on a warm summer’s evening, it’s hard to imagine the place caked in snow and humming with thermal-clad snowsport enthusiasts, clomping about in between sessions on the slopes. The place is deserted but for the odd wispy looking figure sauntering from hotel to deserted eatery. Plenty come here to ski down. Far fewer are mad enough to run up.

That’s what we’re here for, though. This is the eve of the 6000D, a 66km slog through the mountains, testing the toughest ultra runners to their limits with some 4000m of ascent.

Alongside this monstrous challenge, the less taxing 22km Trail des 2 Lacs is also taking place. A taster, if you will, of the real McCoy. And it’s this shorter version that MR has come to run.

We’re picked up early next morning along with a lithe-looking fellow from a French trail-running magazine and deposited in the next resort down the mountain. No amount of course map study can give a clue as to which direction we’ll be heading once we’re through the giant start arch, but once we’re under way, the challenge begins immediately to reveal itself.

The course opens out after two or three switch-backs to reveal a vast, open grassy plain and jaw-dropping views of the mountain range set against a crystal blue sky.

Grass soon gives way to stone and the next uphill trudge reveals itself as a trail of runners stride their way up a sharp left turn. The altitude soon becomes apparent as we start to pass piles of snow either side of the track before reaching the first checkpoint of the race. A crowd has gathered at the first summit of the course where we’re scanned by the race marshals prior to beginning a welcome descent.

The descent leaves the road rather abruptly becoming a single track peppered with unstable rocks and trickling streams. This is where my mountain-running naivity is betrayed as others hop from rock to rock, zipping down the treacherous path while I crab my way down like a drunk at a wedding trying to make it to the bar before last orders.

The bare rockscape has given way to lush greenery at on the valley floor with the soft squelch underfoot allowing welcome influx of ice-cool water into my shoes.

The respite doesn’t last long before we’re confronted with a mini-waterfall to clamber up and another smaller checkpoint marking the end of the ‘easy’ part of the course. The next rocky climb awaits.

A line of towering ski-lift pylons plot our way to the last summit of the day. The final descent is far less technical, presenting only the simple trade-off between the speed at which I want to plummet and the amount of damage my quads and feet will incur as a result. The finish eventually appears as I cut through a space between two chalets. A 22km run has taken me 3hrs and 45 minutes.

The Trail des 2 Lacs finish is nought but a mere checkpoint for the 66km runners. As I fill my face from the food table, the ultra athletes are gathering what they can before carrying on. I feel a bit of a fraud as I wait for the bus back to my hotel and a warm shower.

Suitably clean and seizing up by the minute, I make it to the main town to watch the 6000D finishers filter home, some hand in hand, others with the rictus grin of the utterly spent.

The town truly is the centre piece of the finale to an epic day. Once the last few runners have found their way across the line, a crowd gathers on the green to see the various category winners crowned.

As well as the 6000D and Trail des 2 Lacs, there is also an 11km event and kids’ race. This an event for hardcore ultra runners that strives to cater for all the family. Just make sure the kids have got plenty to do while you’re hauling yourself through the mountains; you might be some time.

The 2014 6000D Takes place on July 26 and 27, http://www.la6000d.com/