You know Warnaco (WRC)? The apparel maker owns a bunch of midsized brands like Calvin Klein, Chaps, Olga bras and Warner’s underwear. And one other very relevant brand: Speedo, the maker of the swimsuit that’s helping 23-year-old Olympian Michael Phelps smash all those world records.

Speedo’s new LZR Racer happens to be the most technologically-advanced swimsuit in history. My friend Susan Casey describes the suit in a smart and very entertaining story, “The Quest,” in Sports Illustrated. “If there ever was a low-tech sport, you’d think it would be swimming,” she writes. “You’ve got water; you’ve got the human body. But wait: There’s the suit.” Casey explains that the full-body LZR Racer is made of a new fabric covered in denticles, like a shark’s skin, to reduce drag in the water. Designed with help from NASA, it’s laminated, trussed, bonded and welded to assure that the contours of the human body are “wrestled into sleek submission.” Casey adds, “To call this a swimsuit is to call the Space Shuttle a plane.”

A front-page story in Tuesday’s New York Times notes that the LZR Racer is viewed by some as technological doping — the closest thing to performance-enhancing drugs ever to come out of the apparel industry, Nike (NKE) included. Nine of the 10 world records that have been broken through Tuesday night at these Olympic Games have been by swimmers wearing the new Speedo. Phelps, who wears the LZR Racer, has shattered three of those records.

Scanning Warnaco’s quarterly results that were released last week, I’m surprised to see that Speedo isn’t performing as well as the company’s other businesses. While sportswear revenues rose 29% to $249.4 million, thanks to a reenergized Calvin Klein business, swimwear sales increased just 2% to $81.7 million. Last I visited Warnaco, it was led by Linda Wachner, the rough-and-tumble boss who still likes to boast that she is the only woman who pulled off a hostile leveraged buyout and was the second woman ever to head a Fortune 500 company. (Katharine Graham of the Washington Post (WPO) was the first.)

In 2000, I wrote a story, “Seventh Avenue Smackdown,” about the vicious battle between Wachner and Calvin Klein himself. The brand-name designer charged that Wachner was destroying his brand image by distributing his jeans in low-rent discount outlets. For Warnaco, wranglings with the SEC, a Chapter 11 filing, and Wachner’s ouster followed. It took a while for new management to recover from all that trouble. But the lesson may be that investing in old brands, like Calvin Klein and Speedo, can make a company relevant again.

P.S. Susan Casey, who wrote that SI story about Michael Phelps, knows water like no other author. Her best-seller, “The Devil’s Teeth,” is a riveting story about sharks and the scientists obsessed with them. She’s now working on a book about the quest by the world’s greatest surfers to ride the first 100-foot wave. Waves that size didn’t used to exist, she says. They do now, thanks in part to global warming.