Being effective during a high mountain trail is fairly simple and can be summed up in two abilities
Running a long time
More seriously the first of these two abilities can be replaced by a VMA (Vitesse Maximale Aerobie) index and the second by a staying power index
VMA is the effort you can keep up for six minutes. In this case there are three VMAs : an upward VMA (depending on the runner’s capacity, the slope and the type of ground) a classical VMA (on flat ground) and a downward effort (not qualified as VMA because our aerobic system is not working at its full capacity). The ideal runner in this case will be able to run on all grounds.
Staying power index means to what extent the runner will be able to maintain a high VMA index throughout his running. It is interesting to note that women runners are generally more effective in terms of physical and mental endurance than their masculine counterparts. (see our article “Women trailers” http://www.wts.fr/trail-feminin/).