By JOHN MARSHALL

Associated Press

PHOENIX — Backpacking is a great way to enjoy the outdoors with the added bonus of getting a little exercise. Those packs are not light and it involves walking most of the time, so you definitely feel it at the end of the day.

The two-wheeled version of backpacking adds a more technical dimension.

An outdoor activity growing in popularity, bikepacking offers the same get-in-touch-with-nature vibe as its two-footed cousin, yet with an added physical challenge as you try to navigate a bike through the woods.

“It’s just fun,” said Scott Morris of Bikepacking.net. “It’s not really an adrenaline rush where you’re doing big jumps or whatever, but there’s still the aspect of being challenged technically where you’re riding rocks and it’s a question of whether you can cross a section or not. Hiking is just walking.”

Bikepacking is a bit like bike touring, but is usually done in the dirt and more lightweight.

Touring bikes usually have large racks and brackets on the back to hold large bags, with bigger bikes to handle the load. Bikepacking bikes are lighter — usually 10 pounds or less — and not nearly as wide, so they can move through narrower areas.

Bikepacking can be traced to the Great Divide Mountain Bike Route, an off-pavement cycling route that follows the Great Divide from Canada to Mexico. Riders who race the route or just do it as a challenge began to create lightweight bags for carrying their gear, and many of the major bicycle companies started to catch on, making bikepacking-specific bags.

Bikepacking got a huge boost in popularity in 2015, when Outside Magazine said it would replace backpacking as the primary means for moving through and camping in the backcountry.

“That was a big turning point, when it started getting real big,” said Logan Watts, of Bikepacking.com.

The idea of bikepacking is essentially the same as backpacking: Pack as much as you can into your pack while making it as light as possible.

While backpacking usually involves one pack, bikepacking has three main bags. One attaches behind the seat, another along the frame behind the handlebars and another roll bag on the front.

Though there are specialized bikes made just for bikepacking, most of the bags can be attached to any mountain bike.

“The bags are designed so you can ride through rugged terrain fairly easy,” Morris said. “You can’t have big bags if you’re going to try a tighter space.”

Some hiking trails are not designed for bikes or even allow bikes to be ridden on them. Bikepacking can be done on single-track mountain-bike trails, but as Morris puts it, “You may end up carrying your bike more than you ride it.”

Riders will often hit established trails, but also will follow dirt and gravel roads, where they can pick up the pace and cover more mileage. It also allows them to go into a town or find a gas station for food or medical attention, if they need it.

“You have the ability to bail out and get to towns to resupply,” Morris said. “It’s nice knowing that you can get to the next town if things get bad and get somewhere if you need to.”

Even when riding established trails, bikepacking can get technical. Hikers have to watch where they’re walking to avoid twisting an ankle, but bikepackers must pay attention to what’s on the trail and also what’s overhead, because impediments can come up quickly when you’re on two wheels.

“A lot of people who have been riding mountain bikes for a while already have that skill set, and are using it to ride into deeper terrain or use it to travel elsewhere,” Watts said. “But you can travel on dirt roads, gravel roads or trails and see different parts of the country, too.”

In this June 23, 2009 photo provided by Scott Morris, Lee Blackwell and Chad Brown are shown bikepacking a segment of the Arizona Trail, south of Flagstaff, Ariz. (Scott Morris via AP)

In this June 23, 2009 photo provided by Scott Morris, Lee Blackwell and Chad Brown are shown bikepacking a segment of the Arizona Trail, south of Flagstaff, Ariz. (Scott Morris via AP)