Slovenian 12 hours

Lessons Learnt

Simen Holvik
4 min readJun 7, 2024

Below notes are my lessons learnt from the race. These are meant for my own use, but maybe you also find something interresting. Good read! And let me know if any questions and or comments. I also created a YouTube video with first reaction (right off the bat). Available from this link.

1. Negative

  • Opening pace too agressive. The first four-five hours I averaged at 4:29 min/km. I should have been between 4:40–4:50 min/km. Must be more at plan. (150km at 12 hours is 4:48 min/km pace)
  • My leg, specific my left leg, got really stiff and close to cramp many times after five-six hours. I suspect that this is due to Altra Vanish Carbon 2 being to stiff / agressive for my pace — and of course a too fast opening pace. Go back to use Altra Vanish Carbon 1.
  • I was slightly dehydrated (ref. below item)
  • The 250ml softflasks are making me drink less. Go back to use 500ml hard plastic (the big lid makes it easier to chug). And, do not use sportsdrink — but pure water in combination with 2 x Electrolyte capsules. Get energy from gel and chews.
  • Remember to use suncream
  • Need to get a singlet, t-shirt, long sleeve and hat in ligther color than black.
  • Issues with airpods for charging. The left airpod has issues. Need to be looked into.
  • Eyes on the road!!! I was unfocused and caused myself to trip over on a roadblock while I was looking at my playlist. Stupid me.
  • I got severe chaffing (blood) at the ancles after less than 3–4 hours.

2. Positive

  • No GI issues. Very happy with the carbloading — and the prerace breakfast. I used close to the same approach as for my last race, Ultrabalaton, except that I only had two days of carbloading instead of three days. Stick to this plan for the next race.
  • Consuming the gels and chews worked out very well.
  • Had a few caffinated gels at for the last four hours. Very good response (but maybe too much).
  • No intensive peeing at the start (which I struggled with at Torino). I peed only once during this race.
  • Support crew very good.
  • Socks, underwear, shorts and watch very good.
  • And a very good event!!!

— —

3. Pacing

Ref below pace chart. Some notes:

  • The first dip at 3h 40min was the first (and only toilet break)
  • Average pace was around 4:30 min/km for 4h 30min, then it slighlty drops
  • I had my fall at hour 6, but from the chart — I see that my pace had already dropped way off the required 4:48 min/km by that time). After that it was all about surfring in and do a best effort.
  • I give myself 1 out of 10 for the pacing strategy!

4. Fuel and nutrition

I consumed following. All products from Precision Fuel and Hydration.

  • 6 caffeinated gels = 180g carbs, 600mg caffein, 0mg sodium
  • 11 gels = 330g carbs, 0mg sodium
  • 7 min & lemon chew = 210g carbs, 0mg sodium
  • 4 original chew = 120g carbs, 0mg sodium
  • 4000ml sportsdrink = 240g carbs, 4000mg sodium
  • 250ml with Coca Cola = 26g carbs, 0mg sodium
  • 28 electrolyte capsules = 0g carbs, 7000mg sodium
  • 3500ml water

In total:

  • 1106g carbohydrates
  • 11g sodium
  • 7750ml fluid
  • 600mg caffein

This results in following key figures:

  • 92g carbohydrate per hour → Very good. As per plan.
  • 646ml fluid per hour → Maybe too low. It turned out to be very hot. Maybe I should have done 1000ml per hour.
  • 1419mg sodium per liter fluid → Very good. As per plan.
  • 8.3mg caffeine per kg body mass → Too high. Recommended consumption is 3–6 mg per kg.



Simen Holvik

A professional Norwegian ultra runner, adventurer, speaker and writer