10k in a day – on a slackline

Endurance Slackline World Record over the Aare River in Bern, Switzerland

Link to a Newspaper article (German)

Link to media report (German)

Link to Crowdfunding for sustainable slacklining in Bern.

Timelaps of the day:

10km on a slackline (waterline) in a day from SLACKATTACK – Slackline Crew.

Saturday, 30.06.2018, 3am

It’s not my strength to get up early, but I knew it was the key to go for 8k on a slackline, especially since we would try this over the river on waterlines.

This 8k mark was set by

  • Joshua Leupolz,
  • Lukas Irmler,
  • Samuel Volery,
  • Quirin Herterich and
  • Alexander Schulz

in Mai during the first Highline FundRACE in Zürich, Switzerland where 12 Athletes walked as many meters as possible on 6 parallel 140m Highlines. At the FundRACE 100m segments were taped and the athletes walked back and forth between those, walking the highlines 80 times or 8k in a day. I have no clue if anyone has tried to walk more than 8k in 24h or one day. This nr. just popped up during this event.

Picture from the Highline Fundrace, organised by Swiss Slackline and the ISA.

The idea was to try something different, but still comparable in terms of distance, here in Bern. For ourselves, but also as publicity for our crowdfunding campaign to build large slackline and waterline posts along the river at our favourite spots in Bern.



Nick arrived by foot and i came by bike to our spot at Dalmazi in Bern, Switzerland. As we were making the connection of the lines on the bridge, the police stopped in their car, a policewomen asked me what we were doing. I breefly refrained from talking, but before I could answer she said – «Its just the slackliners». I laughed and answered we were starting out early today.

They left and it was still dark, the street lights and the reflections in

Setting up the lines in the dark, we did not use a headtorch to attract attention.

the river gave us enough light to rig the 3 lines for this 8 kilometer attempt:

  1. 45m and later 40m PES Balance Community Feather with about 5m sag (rodeoline)
  2. 35m and later 30m PA Slacktivity Pinktube with about 4m sag
  3. 26m PA Landcruising Sonic with about 1.5m sag

This means that the forces on all the lines and anchors was usually somewhere between 1.5 and 3.5 kN (150-350 kg) with us on it.

The segments we taped were:

  1. 28 and later 21.5m
  2. 25 and later 17.5m
  3. 15.6m

We did not rig the 65m because one tree is in bad shape, and not meant for such sessioning. This is one reason why we need slackline posts along the river (link to the crowdfunding). The segments were shortened due to changes in the length of the lines after a couple hours. Also there is a large no-fall zone on the riverbank side, and we also avoid having to turn in the immediate start and end zone where the lines were steep. This meant we had to turn more, we were willing to take that chance. Each of

us did several hundred turns during the day.

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We finally stepped on the lines for the first time. But shortly before that I smashed my finger during warm up and was bleeding before I stepped on the line. Then I also miscalculated the tension on the rodeoline, which meant I landed in the river on the very first try, not a good start. I wanted to begin with dry feet, since I knew they would suffer the most, especially if they got wet alot.

I also wore knee pads during the day to keep my knees warm all the time – they can definitely become a weak point when endurance slacklining. I wore a hat and sunglasses. I protected my ears from a sideways impact with a waterproof music player, which I used to listen to music, although I did turn it off from time to time. The hat, walkman and sunglasses were attached to a headband with a short string.


Breakfast, we both felt tired and progress was slow. A nice steady wind is one of the key factors that can make a line easier to walk. This is especially noticeable on longer lines, but I now also felt the difference after sessioning these smaller lines without the slightest breeze. We also decided to add no windstoppers, if not necessary. I also decided to go for shorter sessions, with lots of pauses and do more of those – instead of going for a couple long sessions.


All we did so far was walk, eat and drink, we had very little pauses. We reached about 2.5k and where exhausted already, our knees and shoulders were beginning to hurt a bit. We thought about giving up for the first time. My feet were burning, I switched to using soleruner shoes. Nick continued on bare feet. I took a 15 min speednap.


With 3.5k each the progress was slow, we talked about giving up for the second time and thought about chilling during the afternoon… we did not. The light reflections from the river made us walk with full sun protection. Nick started to complain about his feet hurting.


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It was hot, record temperatures for Switzerland with about 30 degrees celsius. We used lots of sunscreen and were wearing hats. The cooling river was near, but I knew with every fall my skin would get soggy and therefore weaker.

We both had two involuntarily falls into the river throughout the day. In total together we caught the line about 20 times, almost every time right after turning.


We were at about 6.5k each and the 8k felt within our reach. Giving up now was not an option, we knew that it would be harsh from this point forward. Sometimes it felt like low energy and therefore high efficiency speedlining, staying relaxed was important.

We documented the laps with lists at every anchor and a gopro time lapse with pictures. For future tries I would recommend a high precision tracking (gps, bluetooth, wlan, etc.). What I found before the record attempt was not good enough due to low precision or high cost. If you can think of a solution for this one let ISA Sport know.


We ended up only walking the 26m line (or 15.6m segment) in sessions of 40-50 laps each back to back. Nick and I reached 8k. Oli, our regular guest and juggler congratulated and left. I felt fine, maybe it was the pasta I was eating all day long, maybe

Nick and Tom after 8k, Tom continued for another 2k

the lentils Anita made for me, but it could also just be the sugar from the dates. We definately had too many magnesium tablets. I decided to continue and go for 10k. Nick’s feet were burning, he decided to stop after 8.1k.


The last 500m were painful. It was turning dark slowly and I was in a delirium. I finally finished the last laps and was exhausted – only two people were left for the celebration. Later I found out that i miscalculated and walked more than 10.7k….. We still had to derig and pack all the gear and ride home with the bike. Thanks to Nick, all the helpers, the deriggers, Anita for the massage and the food! At midnight I was happy and sound asleep within 30 seconds.

I challenge everyone to try walking 10k in a day, plan well and come prepared, but basically you can do it with your 15m slackline kit 😉

Written by Thomas, corrected by Marc, pictures by Killian and others, Maggie for the Posters, video by Nick, thanks!