Trail running

Trail running is a type of running that takes place on outdoor trails, often in mountainous terrain, and often includes significant ascents and descents. It is similar to both mountain and fell running (also known as hill running). Unlike road running and track running, it generally takes place on outdoor trails, often in mountainous terrain, and often includes significant ascents and descents. It is difficult to definitively distinguish trail running from cross country running. In general, however, cross country running is a discipline governed by World Athletics, which is typically raced over shorter distances. Runners often cite less impact stress compared to road running, as well as the landscape and non-urban environment, as primary reasons for preferring trail running. This move to nature is also reflected in a large increase in competitors in non-traditional/off-road triathlons and adventure racing in the 2010s. In 2013 International Trail Running Association (ITRA) was formed to promote trail running. ITRA's Performance Index and WMRA world ranking are used to rank runner's performances.