In the weeks before his 14,000-foot-hike up Washington State's Mount Rainier, Paul Klingenstein's training was unconventional, but highly effective.

He would strap his 3-year-old child to his back (about the weight of his Rainier gear) and climb to the top of California's 2,500-foot Mount Tamalpais — twice.

"This seemed like the obvious way to get ready," says the San Francisco Bay Area-based venture capitalist.

When Klingenstein, now 44, did his nine-hour climb four years ago, he was ready, thanks to simulation training.

Whether your goal is a marathon, triathlon, a gargantuan hike, a three-day cross-country ski trip, or a historic trek across Antarctica, simulation is the key to successfully training for the big one.

Liv Arnesen, 47, and Ann Bancroft, 45, who are about to set off for their historic crossing of Antarctica, have turned simulation into both an art and a science. To prepare for the experience of pulling a 250-pound sled through the snow, each woman harnesses herself to three tires, grabs her ski poles and pulls for hours. The three tires weigh only 150 pounds, but the friction of objects grinding on a snowless surface makes up for the missing 100 pounds.

"We move at the same 1 mile per hour that we would if we were doing the real thing," says Bancroft. "This is as close as you're going to get in summertime."

Simulation training for a major physical event is a challenge. We work out in parks and sweaty gyms, which may not be anything like the snow-capped mountain or wild river that we'll encounter during that climb or race.

Even Klingenstein's preparatory hike up Mount Tam lacked the sub-zero, fully glaciated conditions of his snow-streaked expedition. According to Wayne Osness, Ph.D., a University of Kansas exercise physiologist, your training has to be both as specific as possible and general enough to ensure you're a well-rounded physical specimen.