Fell race courses are often longer than cross country running courses, steeper and unmarked when out on the hills (with a few exceptions). Fell running also overlaps with orienteering. Courses are again typically longer but with less emphasis on navigation. Fell running does sometimes require navigational skills in a mountainous environment, particularly in determining and choosing between routes, and poor weather may increase the need for navigation. However, in most fell races, the route or sequence of checkpoints is published beforehand and runners may reconnoitre the course to reduce the risk of losing time working out where to run during the race. Category O events and Mountain Marathons (see also below), test navigational ability, attracting both orienteers and fell runners. Other multi-terrain events, such as the Cotswold Way Relay and the Long Mynd Hike, also qualify as fell races under Fell Runners Association rules.