The Verticale du Grand Serre, in the commune of Cholonge in Isère (France), belongs to the very narrow circle of the world's fastest vertical kilometers. Over 1,811 horizontal meters, it climbs exactly 1,000 meters to reach the summit of Grand Serre at 2,147 meters altitude, with an average gradient above 55%.
A direct line through meadows and grassy slopes, the course leaves no respite. No carved steps like at Fully, but a sustained line of effort where every second counts. The regularity of the gradient makes it an ideal playground for pure performance, provided you can tolerate the intense burn.
This is where Rémi Bonnet, in 2018, broke Kilian Jornet's record (30:25 in 2015) with a time of 30:13 that still stands. The following year, Axelle Gachet-Mollaret set the women's world vertical kilometer record there in 34:01.
The race takes place every year in late September, organized by the Vertik Sport association. The benchmark time for elite runners, under 35 minutes, has become a reference point for the discipline.
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