Forty-five minutes and several runs later, we steered toward Knightslayer, the area’s premier downhill run. The map showed two black diamonds on it: experts only. It was a slender trail snaking through a forest of maple trees and studded with jumps built from mounds of dirt. The most ubiquitous were “tabletops” — steep six-foot-tall ramps, topped with a plateau and ending in another plunging slope. The best riders zip up the ramp, fly over the top and land on the far side. The less brave jump onto the plateau and roll down. At the first tabletop, I barely worked up enough nerve and speed to creep up and onto the top. At that moment my biggest fear was losing so much speed that I would stop on the ramp and fall over backward — an embarrassment I narrowly avoided.

But halfway down the hill, something clicked as I approached another tabletop. The pressure of decelerating as I started into the jump gave way to a brief moment of weightlessness as I became airborne, ending with a satisfying thud as I landed on top and rolled down the far side. I repeated the maneuver on another tabletop, then sped behind Ms. Ide off a four-foot drop, landing with surprising softness.

An hour and a half after class began, she declared us graduates of “Gravity 101.”

We had 45 minutes before the deadline to return our bicycles. I tagged along with a group from Ottawa as we raced to the chairlift like elementary school students rushing to recess. The next few runs down Knightslayer were a blur of whoops and cheers. “I feel like a kid,” said Luc Chabot, a 44-year-old librarian, as he peeled off his body armor in the rental shop, where we arrived five minutes late after squeezing in one last trip down the mountain.

I rode my own, decidedly less souped up mountain bike into East Burke, a tiny village in the trails area. Cars bristling with rooftop bikes filled dirt parking lots. Packs of Lycra-clad cyclists lounged in front of the general store or stood in line outside Chappy’s Ice Cream. Families splashed in the east branch of the Passumpsic River just behind East Burke Sports, the village bike shop. A sign next to the swimming hole read “Please Do Not Wash Bikes in River.” French was as common as English, adding an international flavor. With the Canadian border just 40 miles away, Canadians — many from French-speaking Quebec — accounted for nearly half of the 51,000 visits to the trails in 2011.

The rise of biking has been an economic boon in this remote, hardscrabble part of Vermont. Once largely dependent on fall-foliage watchers and the modest Burke Mountain Resort ski area, inns and campgrounds now advertise mountain biking packages. East Burke’s population of several hundred can swell to over a thousand on a summer weekend.