How is the performance measure in % computed?
The performance measure is computed based on the times realized, and only the times. In particular, the distance, the elevation gain, the type of terrain, the weather conditions, the spacing of aid stations, or the ranking, are not directly taken into account. Only the time matters. You are going to ask: "but how do you know if I have run fast, if you have no clue about the race itself?"
The answer is: by comparing your time to those of the other participants. A simple way to see if you have run well or not, is to compare yourself with a friend whose level you know. For example, if you usually achieve a time that is 10% higher than a friend, but at the last race you were only 5% away, you are going to think that you have run well.
Betrail does exactly this , but using all the participants in the race who already are in our database (and therefore for whom we more or less know the level) and taking the average, and not only those that you know personally. This makes the betrail performance measure much more robust.
To conclude, we take into account the times only, but of course, as the times realized during a race depend on the distance, the elevation gain, the weather conditions, and all that make trail running such a nice sport, we take all of those into account indirectly. This explains also why the same time realized at the same race with the same route another year can receive a different performance measure.
How is the Betrail index of a runner determined?
We take the best three performances realized during today and a year earlier, and we take the average of those three. If you have run less than three races, your index is computed, but you do not appear in the rankings. Your Betrail index can decrease when one of your good races becomes one year old.
What is the Trailcup index? How different is it from the Betrail index?
The goal of the Betrail index is to estimate the potential of a runner at its best. This is why we only take into account the best three performances. The goal of Trailcup is to reward those who run a lot, and fast. By a lot, we mean many races but also long races. Basically each race will earn you points. Your Trailcup index at any moment is the sum of all points earned during today and a year earlier. There is no minimum or maximum number of races.
The amount of points earned at a race are determined as follows. If you run the same race 20% faster, you earn twice as many points. If you achieve the same performance at a race that is two times longer (in terms of duration, not distance), you earn 50% more points.
How do you select which races to take into account for the rankings?
We take races in Belgium, longer than 15kms, which are mostly on non-paved routes, and where the autonomy is substantial (no aid station every 3k). You can always suggest us new races. All this is free of course.
How does this evolve over time?
As Betrail and Trailcup indices are based on races of the last year up to now, they will (potentially for Betrail index) increase with every new race, but also decrease with every race that becomes one year old. We aim at updating everything every week, so expect the rankings to change accordingly.
What does a 100% performance mean?
We have calibrated 100% so that it corresponds to a maybe humanly doable performance (say 2h00 for a marathon).
How is the flat-equivalent distance computed?
We have taken as reference that a 100% perfomance for a 2h00 time corresponds to a flat distance of 42,195 km. For all larger times, we estimate that doubling the distance means multiplying the time by 2.3 (for the same performance). For smaller times, we estimate that halving the distance means dividing the time by 2.1 (to obtain the same performance). These numbers (2.1 and 2.3) have been obtained by analyzing the world records from 3000m to 200kms.