For become a complete trail runnerit is necessary to develop a large number of cardiovascular, muscular, technical, mental qualities…
From a bioenergetic point of view, it is necessary develop the aerobic sector of the capacity center (being able to run for a long, long time) at the power pole (have an efficient oxidative machinery).
Between the two, that is to say from the fundamental endurance to the Maximum Aerobic Speed, is the concept of endurance which corresponds to the percentage of the maximum intensity that one can sustain over a distance or a duration data.
Depending on his specialty, are there areas to work on and others to neglect?
Absolutely not, in particular by virtue of the principle of training polarization. For some ultra-trailers, there is no need to work at the threshold (anaerobic) in a discipline where the average running intensity is less than 60%!
However, in a coastal situation, moreover at altitude, the anaerobic sector is quickly summoned via the use of fast fibers which will provide the necessary power. Short, the entire aerobic sector should be developed, and the anaerobic sector should not be neglected either.
From this perspective, we can better see the interest of combined trainingfor everyone, and especially for those whose training time is not extendable.
Let’s list some advantages of combined training:
- Preparation for race conditions (very changeable in trail running)
- Muscular conditioning (running flat, uphill, downhill)
- Cardiovascular conditioning (through the variety of intensities)
- Fun sessions
- Saves time, therefore increases training efficiency
The purpose of the training being to favor the adaptations of the body and the head to the solicitations of the discipline, the combined sessions respond perfectly to this constraint.
But be careful, do not leave aside the iso-intensity sessions which are essential to the progress of the athlete and which allow major central and peripheral adaptations. Combined training can be placed once a week or a fortnight.
The rules to follow for combined training
- The warm-up time remains the same, or even longer if the session begins with a series at high intensity
- The overall time of the session must not exceed that of a classic session
- Recovery times (and recovery intensities) must be adapted to the sector requested and the objectives of the session. They can therefore be variable.
- The return to calm is the same as for any quality session

Examples of combined sessions
- The pyramid session (rising series, descending series, or true pyramid). It is certainly the most classic and most used combined session, which can be done by time or distance.
Examples: 1-2-3-4-5 min from 100 to 85% VMA or PMA depending on the place of performance, with recoveries of 30s-1min-1’30-1’30 trot
Or 1500-1200-900-600-300m, from 90 to 105% VMA.
Note that in kind it is preferable to work over time!
Or 1min-2min-4min-6min-4min-2min-1min, from 100% to 85% VMA or PMA
These sessions sweep the intensities from the threshold to the VMA.
- The uphill/downhill session. Instead of devoting one session to the hills and one session to the descents, it is interesting to combine the 2 forms of work. This allows to work in concentric and eccentric, to have a varied biomechanical work (frequency-amplitude of steps) as well as very different speeds of execution (according to the slopes obviously)
Examples: First series of 10 x 50m uphill at 15-20%, second series of 10 x 80m on the same slope.
Or 10 round trips on a slope of 50 to 100m, directly linking uphill and downhill, and 30s of trotting at the bottom of each descent. To vary the neuromuscular work, you can change by taking the recovery time at the top and by linking descent-ascent as quickly as possible.
- The “speed-tempo” session. We put quotes because the notion of speed is relative here.
Examples: 5 x 300 – 5000m – 5 x 200m, with 1min trot between the 300m and before the 5km, then 2min trot after the 5km, and 45s trot between the 200m. this type of session can be declined indefinitely. The interest lies in the contrast between the gaits, the organism having to adapt very quickly.
In kind, this session can become 5 x 1min/1min + 20 min tempo at 80-85% PMA, + 5 x 30/30.
- The hill-flat-descent session, very interesting for trail runners. It consists of a climb at racing intensity (and a variable elevation depending on your specialty, from 100m d+ to 1000m d+), followed by a flat tempo, then a rapid descent on the same elevation. Here, we get as close as possible to race conditions. One can imagine a series of work on a well-defined short circuit, for example 100m d+, then 1 km flat, and 100m d-, with return to the start in recovery mode. This type of circuit is completed in 10 min for experts, and up to 15 min for the slowest. You can take advantage of this type of session to work on pacing; that is to say that the terrain varies, the speed varies, the muscular demands vary, but the intensity remains substantially the same.
The combination possibilities are endless. The more varied the session (within the limits described above), the more the body will be forced to adapt and better tolerate the constraints of the discipline. The multiple objectives of such sessions help to strengthen motivation and improve learning.
And then let’s not forget the virtues of fartlek, the combined session par excellence, but whose codes are to be created on D-Day according to the terrain and your desires. Fartlek means “racing games”, quite a program!
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