By Landon Hall

The Orange County Register

(MCT)

Shay Sorrells did it. The Newport Beach, Calif., social worker lost nearly half her body weight, got to revel in her accomplishment on "The Biggest Loser" finale again, and deposited $52,000 for her efforts, courtesy of a Subway promotion. She's earned some time off.

Yet she's taking on Subway's next challenge: running a marathon (with fellow Subway pitchman Jared Fogle, no less) by the end of the year. If she accomplishes it, the sandwich chain will double the money it gave her for losing $1,000 a pound in the run-up to the "BL" Season 9 finale last week.

On the finale, when Fogle suggested the idea, she said "Yes! I'm in." A week later, she was still game. "It's for real," she said Tuesday. "It's absolutely for real. We're doing it."

Sorrells weighed 476 pounds when she started on Season 8 last year and had never run a mile in her life. She tried once, in a P.E. fitness test in high school, and vomited. After that, she always brought a note from her doctor, saying her asthma made running unwise. In the season debut, she completed that distance (half of it on the beach), ditched the inhaler in Week 6, and never looked back.

Today the 5-foot-8 Sorrells is 252 pounds and goes on two short runs a week (3-4 miles on the treadmill), then a long run (7 miles) outdoors. She's also been swimming and biking intensively. But is she ready for the toll a grueling 26.2 miles will take on her body?

Jimmy Summers, assistant manager at A Snail's Pace running store in Laguna Hills, Calif., is concerned. He's run two marathons, and many more half-marathons and 10Ks, and as part of the chain's "running academy" he helps runners of all ability levels train for marathons. "There's always a price to pay if you're not prepared for it, if you haven't trained for it," he says. "The potential for injury — to legs, shins, feet, knees, back — is very real."

Summers says runners should be logging 5-6 miles per run three times a week for six months, even before they begin serious training for a marathon, which can last another six months. But Shay has been on a fast track from the start.

She says she's got many smart people helping her, including "gait doctor" Christopher Powers of the University of Southern California. She said she's not worried about how many hours it'll take to complete the marathon, and that she may end up walking part of it. (Summers says walking 26.2 miles takes training too). And she points to other "BL" alums who have competed in marathons and triathlons. "Biggest Loser has blown away the statistics and people's expectations."

"I'm gonna go out there and do my best," she says, "and I know I'll finish. ... But I'll do it carefully."