The sport of slacklining and highlining has deep roots in Yosemite National Park, going back 40 years. Early pioneers like Chongo Chuck, who some call the godfather of the sport, practiced walking tensioned one-inch webbing between tree trunks. Slacklining is about balance and movement, and as Chongo walks the line, his frame swings gently back and forth over the ground. It may look effortless, but slacklining requires a strong core and hours upon hours of muscle memory.