LUMBERTON — Thousands of local residents have gotten in line to do their part in trying to improve the health of Robeson County, which always ranks low in North Carolina in terms of overall health measures, including obesity. Planet Fitness, one of the country’s fastest-growing chains of fitness centers, opened Thursday at 2770 Roberts Ave., and company officials say it already has 3,000 members. The address is that of the former 95,000-square-foot Kmart retail store that closed in the spring of 2016, idling a key piece of real estate in Lumberton, at Roberts Avenue and Interstate 95. Two more tenants will be opening in the building soon, Big Lots and Ollie’s Bargain Outlet, according to Robert Britt, vice president of K.M. Biggs Inc., which owns the building. According to information provided by Planet Fitness, monthly memberships begin for as little as $10. The center, which will occupy 24,000 square feet of the building, has more than 200 pieces of brand new cardio and strength pieces, and features two separate areas of equipment that company officials say many gyms don’t offer. The center will offer a “a 30-minute workout space that consists of stations where members can ta...