BLAZING OWN TRAIL

After they see his wife running downa rocky trail at a good clip at a race, her pregnant belly bouncing under her sports bra, they usually approach Scott Livingston "The spectators get concerned about her," Scott said in an e-mail. "They often ask what her doctors think. I've told them that the doctors

Debbie Livingston of Bolton is an ultra-marathoner and national class trail runner. She has been racing 50Ks and 50-milers for years and ran her first 100-mile trail race, the Javelina Jundred, last fall in Arizona, finishing as the second woman and ninth overall in 20 hours, 17 minutes. She has outright won trail races such as the Vermont 50K.

Debbie, 34, trained and raced when she was pregnant with her 3-year-old son, Shep. The Livingston's second child is due Sept. 19 and Debbie has raced and trained through this pregnancy, too.

A decade ago, there were few guidelines for pregnant elite athletes. Some doctors were reluctant to allow pregnant women to surpass a heart rate of 140 beats a minute while exercising, a guideline the American College of Obstetricians and Gynecologists set in 1985. In a later report, the heart rate limit was eliminated and the ACOG stated that most women "can exercise moderately to maintain cardio-respiratory and muscular fitness throughout pregnancy and the postpartum period."

In 2002, the ACOG issued new guidelines, stating in part, "Generally, participation in a wide range of recreational activities appears to be safe during pregnancy; however, each sport should be reviewed for its potential risk and activities with a high risk of falling or those with a high risk of abdominal trauma should be avoided."

So running is fine. But where does that leave Debbie, a trail runner who runs through woods, down rocky slopes, up mountain paths studded with ankle-twisting roots?

She is not worried, even if others might be.

"When you fall, do you ever just throw your arms out and fall flat on your belly?" she said.

"Not usually. There's so much amniotic fluid, it's so padded and protected, you'd have to hit pretty hard and just right for anything to go wrong."

A fitness instructor, Debbie knows her body. When she's not pregnant, she runs 50 miles and bikes 30 miles a week. She teaches yoga and Pilates and is constantly monitoring her balance and how she feels.

And she has fallen. She raced the Mount Greylock (Mass.) Half-Marathon trail race ? for the eighth time ? June 21 on a rainy day.

"It was very slippery," she said. "I fell once forward, but it was knees down, hands down.

Or you tuck and roll. That's the normal instinct if you're used to doing trail races. Maybe someone else might not have that instinct.

"As I was getting bigger, I wouldn't bomb [down] those hills like I normally do. People were actually able to stay with me on a hill. Uphill is a different story. The lung capacity, the quads just don't have it. Fuel intake was also a concern. I drink a lot, eat a lot, bring a lot more food."

With the pregnancy, Debbie has gained 18 pounds. A new doctor she saw recently was concerned about the low weight gain, she said. Debbie is not concerned. She is 5 feet 1. Her husband is 5-5. Shep is small; he was 5 pounds, 5 ounces at birth.

"We're going to have a small baby," she said. "I weigh 100 pounds, normally. With Shep, I gained 19. It was a consistent increase but not what the doctors are used to."

Dr. James Pivarnik is the president of the American College of Sports Medicine and a professor of kinesiology and epidemiology at Michigan State whose research involves exercise and pregnancy. He wrote in an e-mail, "Now we are saying that the athletes can continue what they were doing within reason, as long as they keep their doc in the loop and be wary of symptoms."

Pivarnik referenced the 2002 ACOG guidelines, which also state, "In the absence of contraindications [including risk of premature labor and certain health conditions], pregnant women should be encouraged to engage in regular, moderate intensity physical activity to continue to derive the same associated health benefits during their pregnancies as they did prior to pregnancy."

The guidelines also state, however, "The information on strenuous exercise is scarce; however, women who engage in such activities require close medical supervision."

Debbie recently stopped racing, but she still works out.

"It's all relative," she said. "I cut back a lot, compared to what I normally do. I'm biking 16 miles, running 5-10 miles a week. We'll go for a walk or hiking an hour or two. There's yoga, four classes a week.

"The best thing for me is to inspire other women. They don't have to do it to the extent I'm doing it. At trail races, some of the women say, ?That's so great for you to be out here.' Other trail running women are like, ?It makes me feel more comfortable, knowing if I get pregnant, I can still do what I want to do, and it will be OK.' " "We are accustomed to pushing ourselves to the limits of endurance and often in each other's company," Scott said in his e-mail. "We have shared experiences in extreme conditions. That training is what makes her unique and why she can do things at seven months pregnant that others couldn't dream about. I share her sense of adventure, and I'm pretty certain that our kids will, too."