Ran my first race over 100 km in September – Julian Alps Trail 120K (124 km, ~5,900 m, 9 pm start). Finished in 21:27.
Afterwards I went through my watch data in 200 m segments and compared the first 40 km with the last 40:
- Climbing: 662 → 584 m/h (−12%)
- Descending: 1,240 → 709 m/h (−43%)
- Heart rate: 145 avg first half, 122 second half
Compared to my own pace before km 75, I lost roughly 2.5 hours – about 1 h on descents, 1 h on flat runnable sections, and only ~20 min on the climbs.
Context: on short mountain races, descending is usually my strength. But I only started proper run training in June (mostly cycling before), so my guess is my quads just weren't built for that much braking. Engine fine, legs gone.
My plan after my next race: a downhill block, plus a simple test – same descent 4x in one session, compare descent 1 vs 4.
For those who've done a few of these:
- Did you see the same pattern in your first 100K/100M?
- What actually worked for you to build downhill durability?
I put the charts into a short video if anyone wants to see them: https://youtu.be/atUT833fvDo?si=_t2kcQrkF0o8ZKwL