Trail running is a cross between hiking and road running, and appeals to people for a variety of reasons. For some, hiking doesn't carry enough cardio oomph; others find road running unbearably tedious. Trail running is defined as running off paved roads; it could be jogging up a mountain, running on a dirt road or scurrying over rocks and roots.

Although the activity itself is similar to road running, trail running is a unique experience: There are no traffic lights, cars, horns or traffic issues to contend with; it's quiet; it can be beautiful; and trails appear to change every time you run.

"Pavement is pavement," says Nancy Hobbs, founder of the All American Trail Running Association (AATRA) and coauthor of The Ultimate Guide to Trail Running. "But mountains and trails are so unique. Even running them one way or the other or running them in various seasons makes them seem different each time."

Then there's the challenge of navigating the different terrain. You have to traverse grass, rocks, dirt and roots as well as uphill climbs and downhill runs. It's rarely monotonous.

How to Get Started
Two things to remember when starting to trail run: First, think time, not distance. Since it takes you longer to run on rolling hills, it's better to determine a length of time to run. If you usually run for an hour on the road, shoot for 45 minutes on a trail. Second, walking is allowed.

"Sometimes the trail dictates that you walk or hike based on the steepness or the terrain. Or, you want to check things out," Hobbs said. "It's not always about speed. It's about the experience."

If you're in a metropolitan area such as New York City, you're probably wondering where the heck you're going to find a trail. Granted, the Central Park reservoir trail is dirt; however, it's probably not what you pictured trail running to be like. But a quick ride on the Staten Island Ferry will bring you to the miles-long Staten Island Greenbelt. Its rolling hills will make you feel as if you're in the country without leaving the city.

To find trails near you, start with the AATRA Website, TrailRunner.com, which lists popular trails in each state as well as helpful related links. Or consult a local running club for information. Additionally, many publishers put out regional trail running guides. "Trails are available all over," Hobbs says.

Mastering the Technique
Rule number one is to watch your footing. Hobbs advises planning your footfall two steps out. "On the trails you have to be more alert, and you have to watch where you're going," she says. "I tell people, if you want to check out a view, don't look up while you're running. Stop if you want to see something, and then resume running."

Adam Feerst, who leads trail running clinics through his business, Run Uphill Racing, cautions that you should look down with your eyes and not bend at the neck. Keep your head in the direction you're moving. Bending at the neck, he warns, can restrict your breathing. His top tip is to be aware of your alignment.

"Certain key points in your body should be aligned: ankle, hips, shoulder and head," he says. "Almost wherever your foot hits the ground, you should be able to draw a straight line between those points."

The importance of aligning your body is not unique to trail running. However, running on trails tends to magnify your flaws. You might be able to get away with bad form on the road, but on the trail, those errors will sap your energy.

When running downhill you want to be leaning forward, Feerst says. Most people lean back, but that movement will stop your momentum. He suggests trying a gentle sloping jog. "When it starts to get steeper or more technical, slow your momentum down before you get to that point, and do a stutter step," he says, referring to a short, quicker step.

As for uphill technique, push off from the balls of your feet, as if you're climbing stairs. Do not bend over. "When you bend over, you're closing off the hip joints and your hips cannot move forward," Feerst says. To help guide your hips forward, you should drive your arms and shoulders back. You need more power to drive against gravity, and if you push your arms back, it propels your legs forward.

"Always maintain a steady effort level, especially in longer runs. Don't run uphill hard and downhill easy," he says. And always observe your comfort level.