How do you run 26.2 miles if you have trouble making it around the block? With good coaching, discipline, and lots of group support, as NOVA shows when it follows 13 generally sedentary people through a training regimen designed to prepare them for an ultimate test of stamina and endurance. Created in cooperation with the Boston Athletic Association, which granted NOVA unprecedented access to the 111th Boston Marathon, and Tufts University, Marathon Challenge takes viewers on a unique adventure inside the human body, tracking the physiological changes that exercise can bring about.

Former Olympian and three-time Boston Marathon winner Uta Pippig offers advice and inspiration to NOVA's runners throughout their training. And veteran Tufts University coach Donald Megerle guides them week-by-week through an onslaught of physical and psychological challenges. NOVA's runners range in age from 22 to 60, and they come to the endeavor with a wide range of medical histories and backgrounds. They share one thing in common: none has ever run a marathon before.

Team NOVA includes Betsey, a hospital administrator who became substantially overweight while recovering from surgery; Jonathan, a hard-charging CEO and father of five whose marriage is breaking apart; Sama, a reformed smoker mourning the recent death of her mother to a hit-and-run driver; Larry, a social worker and 14-year survivor of a serious heart attack; Xenia, a woman turning 40 and struggling with being an "aging sedentary physician"; and Steve, a Harley-riding former NFL linebacker who sees the marathon as a novel challenge for someone used to running only a few yards before tackling an opponent.

Together with their teammates, they undergo a battery of physiological tests conducted by Tufts scien¬tists to gauge baseline levels for weight, maximal oxygen uptake, and other health and fitness factors. These same tests are performed again at the completion of the training to chart each runner's response to increased activity

And increase it does, albeit slowly and under the watchful eyes of Megerle, Pippig, and other exercise specialists, who shepherd the novices from relaxed workouts to demanding long-distance runs. Injuries take a toll, but the group meets faithfully every Sunday for nine months to prepare for the big race. Physical conditioning is only part of the process; equally important is the psychological support that team members get from their coaches and from one another. "We have a lot of fun. It's almost like a love fest," says Pippig.

As marathon day approaches, the forecast calls for pelting rain, gale-force winds, and the possibility of snow—conditions that daunt even experienced marathon runners. On the day itself, April 16, 2007, those who have made it through training arrive at the race's starting point in Hopkinton, Massachusetts sheathed in ponchos, with dry shoes in plastic bags. Then, at 10:30 a.m., the starting gun fires, and they join 20,000 other runners for the epic race to Boston—a journey that few on Team NOVA ever dreamed possible.