So, you think you’d like to try slacklining at Yosemite National Park? Have a look at this videoclip of the Lost Arrow Spire Highline and see if it doesn’t change your mind.

Libby Sauter, the young lady making her perilous way to and from Lost Arrow Spire in Yosemite National Park has 2,890 feet of air under her. Even with a safety line, that’s got to concentrate a person’s attention. This is what adventure sports addicts mean when they say “live in the moment.”

Slacklining originated in the late 1970s and early 1980s. Many trace the birth of the sport to Yosemite National Park, where serious interest developed and the sport evolved to highlining (see below). By 1985, Scott Balcom had completed the first highline walk at Yosemite’s renowned Lost Arrow Spire, the sport’s most revered venue.

Slacklining has an interesting history. At first, experimenters thought of slacklining as just a fun thing to do to while away time and improve balance and coordination. It took a while for the activity to evolve into a sport in its own right, and equipment improvements had a lot to do with it.

Early slacklining (as differentiated from circus-style tightrope walking) involved just walked loose chains and cables wherever they were encountered – in parking lots, or wherever. Then some people started using climbing web, which is flat and somewhat springy. Eventually, slackliners learned that they could get even better performance from a “threaded line,” which is a reinforced line created by threading 9/16" webbing through the hollow core of the normal one-inch webbing.

Many slackliners opt for the lower-risk variant of the sport that is practiced close to the ground (commonly called lowlining or tricklining). Highliners are slackliners who accept more risk by slacklining under conditions where unprotected falls are result in death or serious injury.

To keep risk within acceptable bounds, the vast majority of highliners (but not all) wear a climbing harness or “swami belt” with a leash attached to the slackline. Additional safety measures include doubling the slackline or running a climbing rope along the bottom of the line(s). Smart slackliners create bombproof anchors and pad all places where rigging can contact abrasive surfaces.

The sport is still in the relatively young, expansive, and experimental stage of its growth. New techniques/methods/tricks and equipment are being developed, new areas are being opened up to slacklining all over the world, and new records (especially for extreme height and length) are being set at a fairly rapid space.

If you want to see something truly insane, have a look at this videoclip of Dean Potter doing the Lost Arrow Spire Highline without security – that is, without using a climbing harness and leash. Unprotected highlining is possibly the world’s single most dangerous sport.