It’s a new outdoor showmanship sport that is gaining in popularity. “Slacklining” is an emerging phenomenon at local beaches and parks and creates plenty of attention with its daring tightrope-like acrobatic appeal.

But the activity has also begun to gain the attention of police and lifeguard officials, who are keeping a watchful eye on safety and permitting matters.

Slacklining involves thick, flat, colorful, nylon ropes stretched between two anchor points — usually trees or posts — and are used by performers to balance on or engage in acrobatic moves. However, slacklining differs from traditional tightrope walking. The rope used to walk on is a one-inch-wide nylon webbing and not tied taut like a common tightrope. The slack allows for stretching, bouncing and jumping.

Offering colorful entertainment, slackline performers frequently attract plenty of bystanders.

Among the popular slacklining meccas in Ocean Beach are Saratoga Park near Abbott Street, along with Brighton Avenue Beach, Dusty Rhodes Park and Robb Field. Each of these locations has plenty of mature trees or posts to tie off the slackline ropes.

Slackliners must, however, adhere to city permitting regulations. And many of the areas in Ocean Beach where slackliners choose to set up their exhibitions are not exactly legal under city law. Under the city’s municipal code, slacklining is prohibited in all areas of Mission Beach Park, Robb Field, Dusty Rhodes and all parking lots.

“When we notice slackline activity, we generally undermine it immediately, provided there are no water-based emergencies, which have priority,” said Sgt. David Rains of San Diego Fire-Rescue/Lifeguard Services. “If everybody was to put up ropes and barriers all over the place, it would post a big hazard, blocking or eliminating public and/or emergency access.”

For locations where slacklining is allowed, participants and performers should be aware the city’s municipal code specifies that:

• slacklines cannot be left unattended and are required to be easily visible with bright colors

• slacklines are not to exceed 40 feet in length or be higher than 4 feet off the ground

• spotters (assistants) need to be present and slacklines need to be removed before sunset.

• the use of cemented posts, young trees and other park structures for anchors is also prohibited and tree protection like cloth or carpet is required at all tie-off points

Other areas where slacklining is prohibited include walks, roads, streets and highways; all beaches by the ocean, including adjacent parks and perimeter sidewalks south of Sunset Cliffs Natural Park and Torrey Pines.

Permits for slacklining at community parks and beaches can be obtained at the local recreation center for a fee, which is based on the number of participants in the group.