Many runners who've spent years running "serious" road and track races tend to look suspiciously on the recent growth and popularity of trail running events. After all, how can you possibly set a new PR on a course that offers hills, uneven footing, narrow trails with little room for passing and even – gasp – non-certified courses?
Even training out on the trail may seem a bit too casual, after all, serious runners should be out on the track or measured road courses where you can keep track of your pace and time and compare the efforts, right?
Injuries are the bane of every committed runner. There's nothing worse for a runner (or anybody who lives with that runner) than being injured and unable to indulge in their favorite pastime.
Trail running surfaces are much softer than the asphalt or concrete you'll find when running around town. Softer surfaces mean fewer injuries, not only due to lower impact forces, but also because you'll build more strength in the muscles that help stabilize your lower leg. These muscles help absorb impact forces and provide more support—no matter what surface you're running on—and that can add up to fewer injuries.
Studies show that running on uneven terrain causes you to take shorter, quicker strides and land more on the forefoot than the heel. These adjustments are helpful when you're running on any surface. Shorter strides, a faster stride rate and mid-foot landing requires less energy and allows for faster acceleration than heel-toe running with longer strides.