1. Running on trail is easier on the joints. Most trails in the Northwest are dirt/earth and woodland trails which are very soft and easy on the knees. A quick Internet search would let you know that the best type of surfaces for runners are in the following order: grass, woodland, earth, cinders, synthetic track, treadmill, asphalt and then concrete. That being said, there are lot of road shoes that help soften the landing.
2. The landscape. Often trails are in remote locations away from the cities. You get to be the in the middle of nowhere, surrounded by beautiful mountains, trees, rivers, wildlife etc... Those trails photos automatically make you an epic runner.
3. I found trail running revitalizing . In my opinion, it is easier on the mind and body to be away from noise, pollution's and the crowd that can be found in urban environments. You don't have to worry about getting hit by a car or a cyclist. I found it easier to run trails at night than running a dark alley in a crowded city.
4. I believe you get a better work out trail running because most trails are seldom flat. If you don't have big hills which force you to walk, you often find rolling hills which provide the best work out. Not having to stop for light is also a plus. Trail surfaces are also not smooth which forces runners to strengthen those small stabilizer muscles that are not often used during road running. You also keep your mind sharp so you can quickly react and catch yourself if you are about to twist an ankle or slip/trip.
5. Finally, being able to run trails allows you to have more options in terms of training and races as you have more places to run. Often, trail races can be less expensive and you can choose among longer distance races such as ultras. It's usually easier for race directors to get permits and they don't have to have cops at each traffic intersection.
For friends that are new to trail running, I usually recommend them the following gear list:
1. Trail running shoes. Trail specific shoes usually come with a rock plate to protect those feet from sharp rocks, aggressive lugs for better traction on slippery trails or slick rocks, and upper material that are more durable.
2. Hydration vest. I always recommend a vest or pack as you are able to carry fluid/food for your run and extra layers in case the weather changes on you. A small emergency kit and a headlamp are great to have in case something happens and you don't have phone reception to call for help. Unlike road running, you don't have the luxury to call of a lift or go to your local bakery shop for a pick me up.
3. Maps/GPS/phone so you can stay on the (correct) trails and find your way back to your car.
Despite loving trails, I still run and find myself racing on roads. I like to mix my racing schedule with trail races as well road races. Roads are more consistent and chances of twisting an ankles or tripping are much lower than on trails. Road running allows you for higher turn over/cadence and a more consistent and faster pace. Running a nice and flat marathon every year like the Eugene marathon allows me to easily gauge my fitness level. Unlike roads, all trails are unique and the same trail can be different based on trail maintenance and weather so it is hard to get a good benchmark. Finally, every runners can run on the roads so it is easier to bring friends that are new to running.
