A fit physique may not be your main reason to head out for a run on trails, but it's not a bad side effect. Running on variable surfaces, such as trails riddled with rocks or roots--or even on smooth, twisty singletrack--forces your body to use stabilizing muscles (hello, core) and strengthen connective tissues (ligaments and tendons) that don't normally get recruited on road runs. And running hilly terrain on trails builds leg strength--working quads, calves, and gluteal muscles more than running on flats.
Plus, research shows that trail running can burn up to 10 percent more calories than running on a road or track for the same time or distance.
The varied terrain of trails engages small, intrinsic muscles situated deep within our bodies for balance, improving coordination by teaching us proprioception.
proprioception \'pr?-pr?-uh-'sep-shun\ n. 1. Awareness of the position of one's body, helpful to runners and all other living creatures.
Running trails has multiple benefits. Science says so!
- Studies show that walking on uneven terrain requires more energy than walking on smooth ground, engaging more muscle activity and metabolic expenditure. If this applies to walking, just think how it applies to running.
- Running trails--unstable ground, uphill/downhill, altitude--often strengthens balancing muscles, such as core muscles and small stabilizing muscles, normally not engaged in road running.
- Trail surfaces are softer than pavement and thus create lower overall impact and reduced pain while running.
- Running trails improves bone density that may help combat osteoporosis.
"Mechanically, trail running challenges athletes in all three planes of motion: sagittal (front/back), frontal (side/side), and transverse (rotational). This means there's a high degree of muscle control and strength, plus coordination and proprioception, required to trail run." — CHARLIE MERRILL, licensed physical therapist and competitive trail runner.
Trails compress, or dampen, to varying degrees with every step. That means that each time your foot hits the ground on trail, the impact is less harsh than on pavement or concrete. This minimizes wear and tear on your body--the same kind of wear and tear caused by the repetitive motion of running on a hard surface, which can lead to a multitude of overuse injuries. And the softer the surface, the more energy your body expends to rebound during your stride--a good thing. Running on very soft surfaces (such as deep sand) increases muscular strength and overall stamina.
"In the same way you go to the gym to get strong, running on changing terrain makes muscles, tendons and ligaments stronger. Compliant surfaces are great for muscles and joints because they store and return your energy. Running in the sand, which has a lot of dampening, works foot and calf muscles and burns a lot of energy. And running on uneven terrain makes your heart rate and overall energy cost go up." — DANIEL FERRIS, PHD, professor, School of Kinesiology, University of Michigan
Easy does it.
Doing too much too soon can shock your body and cause injuries. With any training program, easing into things is important. With trail running, gradually building up to more technical terrain will give your muscles, joints, ligaments, and tendons time to adjust and prepare them to become stronger than ever.