For the third stage of the race, the runners crossed 40 km of mountains and rocky terrain, enduring freezing rain and heavy winds. Normally dry riverbeds had turned into rushing rapids due to the heavy rains. Chow injured his knee during one ascent, popping it when he crouched to "answer the call of nature."

"I called it 'crapper's knee,'" Chow said.

Sometimes, Chow would run with his friends, and other stretches of the race he would complete by himself, navigating the terrain and embracing the isolated nature of the region.

"There were many hours I would be by myself. It's really a fascinating experience when you run by yourself in a foreign place with harsh conditions and you're tired. You really get to know who you are and what drives you and what pushes you. It's almost a spiritual feeling that one gets," Chow said. "It's 80 percent mental and 20 percent physical."

Injury notwithstanding, Chow began the fourth stage in good spirits, but the rain that had chilled the competitors the day before had turned into blistering hot sunshine. The stage required the runners to cross 47 km of valleys and gorges. At the end of the day, Chow watched as fellow runners treated their suffering feet, draining blisters under their toenails with syringes they had brought along.

On the fifth day of running, Chow said he began to question the sanity of racing across the Gobi. The stage, dubbed "The Long March," took Chow across 80 km of 1,500-foot sand dunes and rocky riverbeds that were sometimes full of "foot sucking mud traps." It was then that his knees failed and running became impossible. However, Chow soldiered on, teaming with a French group of runners for the last 30 miles, following a trail of glow sticks in the dark.

It took Chow nearly 16 hours to complete the stage, arriving at the campsite at 2:30 a.m. The sixth and final stage was 11 km into the heart of Kashgar. The runners boarded buses that took them to the edge of the city, and the competitors ran through the winding streets and alleys to end in front of the 400-year-old mosque in the heart of the old city. After the long bus ride, Chow said his swollen knees had locked up, making what should have been a relatively easy stage into one of the most difficult parts of his journey. Crossing the finish line, Chow said he felt euphoric.

"A long race of this sort is almost like a microcosm of life. In your life span you go through all these different stages of hardship, of joy, elation, ups and downs in the way you feel physically and spiritually," Chow said. "But as long as you know the general direction of where you want to go and as long as you are moving forward-you will eventually get there. It's a matter of persevering."

Chow finished in 64th place, with a time of 47 hours, 52 minutes and 7 seconds. Of the 172 runners, 157 completed the race. Following the race, Chow visited Beijing, and then traveled to Xiamen to meet some of his relatives for the first time. The trip was Chow's first to China, though his father was born in Xiamen and his maternal grandparents also lived in southern China. Chow said he "absolutely" plans to make another trip to China, study Mandarin and reconnect with his heritage.

The next desert race Chow said he plans to tackle is the Sahara in 2008, and he has set a goal of finishing in the top 20 percent.

"I can't be lazy in my training. I have to cut another 13 hours off my time," he said.

(Reporting from New York)

Racing the World's Deserts Hong Kong-based RacingThePlanet over the past five years has organized a series of 250-km self-supported footraces across the world's most remote regions. The group's 4 Deserts series takes runners across China's Gobi Desert, the Atacama Desert of Chile, the Sahara Desert of Egypt and Antarctica. There is also a fifth annual race that takes place in a different location each year. This year, the group will travel to Vietnam. Runners from all over the globe compete in the races. The average age of competitors is around 38 years old, and 80 percent of competitors are male. Some have completed the course in as little as 25 hours. Many use the race to raise money for their favorite charities. "We wanted to start a world-class sporting competition and, at the same time, take people to really far-out, pristine, culturally interesting places," said Mary Gadams, CEO and founder of RacingThePlanet. "We want to give people a chance to experience these places before they change, and as you know, places like China are changing quickly." The desert races are unlike any other sporting competition, and often competitors who sign up for just one race end up returning for other races in other deserts, Gadams said. Runners must carry all of their own supplies, except for water and tents. Competitors as young as 21 and as old as 73 have participated in the desert races. "Most people wouldn't trade the experience for anything," she said. The group also supports the local communities where the races take place, supporting charities and schools and raising awareness of local needs. In addition to helping others, racers also achieve many benefits for themselves, she said. "After you've pushed through your physical and mental limits, you realize that you can do a lot more than you thought possible. Confidence is the first thing you gain, and then secondly, a whole network of friends and business contacts in virtually every continent in the world," she said. The races continually are growing in popularity, but Gadams said the group wants to limit the size of the competitor pool to around 200. The smaller group benefits the runners by giving them a more intimate, solitary experience and minimizes effect on the local environment. For more information on participating in any of the desert races as either a runner or a support volunteer, visit the organization's Web site: www.4deserts.com, Gadams said. (Corrie Dosh, reporting from New York)