Traveling in America on an adventure holiday you therefore actually spend a lot of time sat down - on coach rides along the seemingly endless highways; during plane trips from state to state; and on taxi journeys in the city. And after many hours sat sedentary racking up the miles, you get a real urge to stretch your legs a bit.
To give you some ideas for where to stretch your legs, here's a guide to some of the USA's most famous hiking routes.
John Muir Trail, Yosemite National Park
Branded as the premier hiking trail in the USA, the John Muir Trail (or JMT as it is known) was actually named after a Scotsman, who was part of the Sierra Club, an environmental group founded in 1892 that devised the route.
Visitors to Yosemite National Park can walk part of the 210-mile route from the Happy Isles, a group of small islands in the Merced River that act as the northern terminus for the JMT.
Heading south from the Happy Isles, you'll pass Half Dome, one of the park's most iconic landmarks, and Tuolumne Meadows, a lovely sub-alpine area of meadows and pine trees. From there you follow the Sierra Nevada mountains to the park's boundary.
Nankoweap Trail, Grand Canyon National Park
Regarded by the National Park Service (NPS) as the most difficult of the named trails in the Grand Canyon, Nankoweap was devised by the soldier and geologist John Wesley Powell in the 1880s.
He was obviously an adventurous soul with a head for heights as the Nankoweap Trail features some very narrow paths with huge drop-offs to the side, as well as the largest total rim-to-river drop (5,640ft) of any trail. In one section, aptly named 'The Scary Part', negotiating the narrow ledge under a sheer cliff is a real test with a full backpack. To add to the challenge, hikers have to carry and cache their own water as there is none along the route.
The reward for all this hard work: "magnificent views, excellent chances for solitude, and fascinating human history", according to the NPS.
Angels Landing, Zion National Park
If reading about the Nankoweap Trail didn't bring you out in a cold sweat you're probably safe to hear about the route to the top of Angels Landing, a 5,790ft-high sandstone rock formation in the Zion National Park.
Although there are some handrails, the trail features extremely narrow sections with a sheer drop into the canyon below, so this is another potentially vertigo-inducing route.
However, once you reach the summit you're rewarded with a simply breathtaking view of Zion Canyon stretching out before you, flanked by enormous cliffs, making all the effort on the steep and exposed trail seem entirely worthwhile.
Unlike the Nankoweap Trail this route is also very doable in a day, so you don't need to worry about camping out or carrying lots of water and gear.
Whichever trail you choose to do, make sure you've got suitable clothing and footwear, let someone know your route and check the weather forecast before you set out. If it's going to be hot and sunny, leave early in the morning and take plenty of water.
Photo credits: [ThinkStock - iStockphoto]