Athletic parents who've been through it have some advice for those embarking on parenthood for the first time: Don't fret, you'll still get your sweat on. But new parents may have to adjust their workout routines -- what one optimistic Dad refers to as ''cross-training.'' The kid-friendly workouts are no less rewarding -- although the benefits are less about distance and time, and more about building healthy family habits.

''This is such a teaching time,'' said Heidi Hill, of Waterbury, Vt. ``This is a time that [children] model their parents and look up to their parents.''  HOW-TO BOOK Hill wrote a how-to book to assure active adults that, as new parents, they can keep on exercising through the baby years. In Fit Family: The Infant, Toddler and Preschool Years (Vitesse, 2008), she explained how to hike, bike, run, cross-country ski and even kayak with small kids.

Hill, 37, and her husband, Tom Thurston, 45, have done many of these sports while towing along daughters Ava, 5, and Julia, 3. She says parents must persevere through these early years because as the kids get older and more self-sufficient, exercising as a family becomes more rewarding.

''At the get-go, a lot of it can be miserable,'' said Hill. ``You really have to persevere and know that you're teaching a lifestyle.'' Will Chin, 47, of Seattle, is living that fit family dream right now. An outreach administrator for the outdoors company REI, Chin and his wife have three kids, ages 7, 8 and 10.

The kids now want to pursue sports that exceed his own, Chin said. He likes to road bike, and his kids want to mountain bike. He likes to cross-country ski, they want to learn snowboarding. 'They want to take it to the next level,'' Chin said. It wasn't always that way. When they were toddlers, Chin had to modify his workouts to include them. He cut back on his 30- to 50-mile rides and took up ''fast walking'' with a jog stroller -- an athletic downshift Chin cheerfully calls ``cross-training.''

He advises new parents to concede that their outdoor adventures may change, but not necessarily for the worse. He and his wife went from driving an hour to reach a trailhead to taking the kids to Seattle parks and festivals. 'Suddenly, you're seeing things that are close to you that you've never explored before,'' he said. ``The thing is to just stay active.''

WELL EQUIPPED The right equipment makes all the difference, said Hill, who recommends buying both new (bike helmets) and used (the baby jogger). 'Get good equipment for transporting your kids,'' she said. ``Clunky equipment -- a baby jogger that's more for walking, not running -- it's hard to push, and then parents end up not doing it.''

Chin recommends investing in a trail-a-bike, a one-wheel contraption that attaches to the back of a parent's bicycle, allowing a small child to learn the mechanics of cycling while the parent does all the motoring. CHANGE OF PLANS Above all, Hill said, make the most of athletic outings that go sour. She and her husband were excited to take their girls cross-country skiing this past season, but their first time out lasted only a few minutes.

The family went out for lunch instead. 'It's just knowing that some days aren't going to be great, but we're going to put a positive spin on it,'' Hill said. The workouts may require extra planning, different expectations -- and taking along snacks -- but in the end, parents really need to get past their own mental roadblocks.

''I think people tend to find a lot of excuses -- too busy, too much money, the kids are crying,'' said Hill. ``You just really have to educate yourself, and do it.'' Chin recommends checking websites for information about family-friendly hikes and other activities. REI has retail stores in 28 states that post lists of family-friendly local hikes online, he said. Some of the stores sponsor an outdoor school, with some classes geared toward families.