A typical slackline is 10 -20 meters long. But what if a possible line is burning itself into your eye, which extends this dimension? Two beautiful trees in the middle of a lovely meadow. How far apart are they? Will it be possible to tie a line in between and walk on it?
The search for the answer to this question creates the appeal of long slacklines. But longlines have to offer a further unique fascination: they are extremely powerful and dynamic. Once you gain the ability to control this kind of power packet, the game of playing with gravity and strain in order to create a flow is highly addictive.
The term longline is used for lines that are more than 40 meters long. A longline typically has much higher tension and a larger sag in the middle, which influences the walking behaviour of the line.
The ends of a longline are very rigid; very odd for the typical slackliner. Relatively big heights (1.5 to 2.5 meters) add to the challenge. Now, if you mastered the first part of the longline another phenomenon awaits: the mass of the longline starts to swing. This causes a wave which moves through the whole line to the ends, and then bounces back towards the longliner. This swinging needs to be controlled or, better still, minimized. The next challenge is the middle part of the line which is very soft. Because of the big sag in the line, every 'false step' causes the line to swing very widely. Physical exhaustion, especially felt through tightened shoulders contributes to the difficulty. To prevent injuries, it is important to learn a safe technique for falling off the line. Once you leave the middle part of the line behind, it is necessary to stay relaxed and not lose concentration. When you finish the walk, you are rewarded with a burst of intense relaxation, and you feel great satisfaction to have made it across.
How long can a longline be?
Its not easy to find an answer to this. In the first years between 2006 and 2010 an increase in the length of a line was mainly accomplished by an increase of the slacklines pretension. A preliminary end of this strategy was the first 300 meter long slackline walked in 2010, that had a pretension of over 25 kN. This level of tension together with the great length has a high safety risk.
Safety is the central topic when it comes to longlining. The longer the tensioned webbing the higher the stored potential energy, that transforms into movement energy in case of material failure. Flying metal and razor sharp webbing are a serious threat to the slackliner and all living beings around. Therefore, with all the fascination of length, the objective analysis of the physical coherences must always be preserved. Safety is the first priority.
Another approach is to keep the pretension low by walking it with a lot of sag in the middle. The last years showed that this way caused an increase of performance. Limiting is now the amount of sag that is still safe to walk. Naturally the line has to be anchored higher in order to reach more sag. Higher anchors result in higher higher falls wich means more risk of injury. That is why people are searching especially for longline spots with have a favorable height profile, like a huge symetric dip.
However, with great length it becomes increasingly difficult to find such a suitable profile in nature. A limit which does not apply to highlines. For this reason, longlines haven been overtaken by highlines. An astonishing development of which one had not dreamed in the early years of longlines. The provisional end mark for the "classic" longlines (no leash and no backup in jump height) lays a little over 600 meters sice 2015. The top mark of highlining is developing continously, and crossed the 1000 meter barrier in 2016.
It will be exciting for the future to push the markstone of the possible.
Longlining has one great advantage - you can walk for a long time without having to turn around.