Running season is approaching in the northern hemisphere and I happened to notice an interesting research article in regards to trail running. It has been written by Glen Björklund as  first author with whom  have performed one study in Finland at our Turku PET Centre research institute. The study has been published in Frontiers of Physiology, so it is freely available to everyone. It’s major conclusions are that maximal oxygen consumption, vertical running speed and fat percent are important predictors for trail running performance. Performance between runners also varied the most on downhills throughout the course, while pacing resembled a reversed J pattern. But they are discussing also many other things and this paper also has nice introduction to the topic, so it is worth reading if trail running interests you!