Trail running has grown in popularity and is enjoyed through the United States. Trail running takes place along paths that are often inaccessible by road, except at the trailheads. A typical trail traverses through rough terrain, mountains, hills and forests. Common distances in races are between 10 km and 50 km. Participants often ascend and descend thousands of feet through steep grades. People in the Mountain States, the Western US and California are avid trail runners.
Trail runners use specially designed shoes, which have stiffer soles and are more rigid and protective than normal shoes used for road running. Shoe manufacturers in the US like North Face, Nike, Salomon and Vasque specialize in trail running shoes.
Trail running shoes are geared towards keeping the feet dry in wet conditions and comfortable on slick terrain. They are also designed to grip on ice and stablize the feet. All running shoes are designed to provide biomechanical protection from injuries. Road-running shoes are built to provide cushioning and motion control to prevent repetitive movement or overuse injuries such as over-exertion, shin splints and knee pain. Trail-shoe design generally emphasizes on stability, a feature that protects against acute ankle sprain, which is the chief cause of injury in trail running. Trail shoes are tested on a wide variety of surfaces, including single-track, fire roads, jagged technical trails, gravel paths and even pavements.
The industry standard for the lifespan of a running shoe is between 350 and 500 miles. Different models offer varying results. A runner averaging 20 miles per week could expect a pair of shoes to last from 16 to 25 weeks, or about 4 to 6 months. Many factors affect how long a shoe would last, including the runner's weight, the runner's style and the surfaces run on. A trail shoe is required to be sturdier than normal shoe because of the greater wear and tear involved in trail running. Therefore, it is recommended that trail runners wear shoes that are especially designed for trail running.