Trail du Moucherotte analysis

A new approach to trail pacing

Introduction

Last weekend saw the Multisport Festival du Vercors in Saint-Nizier du Moucherotte (the village where I grew up), an event featuring over 18 sporting events, including the Moucherotte trail. Unlike last year, the weather was rather capricious (hail and rain on Saturday, cold wind on Sunday with a temperature of -8°C felt at the top of Moucherotte!!), but for once a sporting event is taking place in Saint-Nizier, I felt obliged to take part!

At 9am on Sunday morning, I set off on the Trail du Moucherotte. A 19-kilometer course with 1300 meters of ascent awaited us. With the route at an average altitude of over 1600m, we were hampered by the snow remaining on the course following a rather generous winter, making progress rather complicated on certain sections. The previous day’s rain didn’t help either, making the descents particularly muddy and slippery.

It was a great trail all the same, and this is an opportunity to give you an analysis of my approach to preparing for the race!

Current state of play

Before starting any race plan, it’s important to take stock of the athlete’s current level (myself in this example) so as to make as few mistakes as possible in the race plan.

The first thing I evaluate before a trail run is the critical threshold (or FTP, CP…). And more specifically, the critical threshold on a hill (at over 10%), which will be much more representative on the trail than the FTP on the flat. The image below shows my performance profile on hills. As a reminder, an article on critical power is available HERE. This is a “physiological” value that I follow closely for long-distance events like trail running, as it reflects the athlete’s aerobic capacity and takes into account his endurance (unlike the measurement of MAP, which is strongly influenced by the anaerobic pathways).

On race day, my critical threshold for hill climbing is estimated at 300 W (see image above). I used this value as a basis for my race plan.

Let’s take this opportunity to review my training since the beginning of the year (to understand how I analyze training, an article is available HERE):

Overall, training was very good in phases 1 and 3, i.e. January and February-March. However, I had some big gaps in my training due to illness (10 days of flu in phase 2 at the beginning of February, and 3 weeks of allergy/fatigue in phase 4 in April). Thanks to the good training phases 1 and 3, I was able to build a solid foundation for the long term. The competitions at the end of April – beginning of May (the legendary Tiomila relay with my Swedish club, and above all my French middle-distance OC title????) helped me regain confidence in my training, despite a complicated April. My form is therefore on the right track, but aware that it was far from optimal, I opted for a fairly cautious race, far from any objective results (well, you never know in trail running ????).

External factors to be taken into account

It should be noted that my critical threshold on hills is essentially based on performances achieved below 1000 meters altitude, living in Grenoble (220m). My 300 watt base is therefore to be adjusted according to environmental conditions, in this case, it’s altitude that will have the biggest impact (temperature too, but that’s more negligible…) on my aerobic performance.

To adjust pace according to altitude, I refer to the work of Péronnet(https://www.ncbi.nlm.nih.gov/pubmed/2010398). To sum up, and without going into too much detail, up to 2500m, aerobic power drops by 1% for every 300 metres of ascent.

On the Moucherotte trail, the average altitude is around 1,600 metres. That’s a theoretical drop of 4-5% compared to Grenoble (220m), or 5% to put it more broadly!

Taking these 5% into account, my critical threshold is no longer 300 W but ~285 W!

My pacing plan

What percentage to choose in relation to this critical threshold?

It’s quite individual and depends a lot on specific trail training, especially hill work. I’d say between 75% and 98% CP depending on the course profile and the athlete’s level/training.

As far as I’m concerned, and given the profile of the race with climbs of 20-30 minutes maximum, my specific training (fairly low), and my complicated month of April, I opted for a fairly cautious pacing.

My plan was to respect a range between 85% minimum and 95% maximum of my estimated critical power, except at the start, where I allowed myself a few minutes above the threshold (a word of advice: avoid staying too long above your CP as this leads to heart rate drift with a drop in your muscular output, and therefore the onset of premature fatigue) to position myself at the start of the race.

My hill pacing range for this trail was therefore planned to be between 242 W and 270 W. My aim was obviously to get as close as possible to the high value of 270 W!

Trail analysis

The snow on the heights disrupted my pacing plans on certain sections, but overall I was able to stick to them. The aim was to stay below 270 W (except for the first climb) and above 242 W. I stuck to this plan pretty well, averaging 262W, 262W and 253W on the 3 main climbs of this trail. In terms of sensations, I had the impression of being able to deliver a fairly constant effort over the majority of the course. The heart rate confirmed these sensations, with good stability around 160-165 bpm.

The graph above shows that I stuck to my plans, with a peak power distribution around 260-270 W and good consistency. There was a slight drop (253 W) on the last climb, however, which can be explained by the onset of fatigue, the altitude (highest point of the course), and the few snowy sections on the trail.

My heart rate also confirms the good regularity, with an average heart rate of 161 bpm over the entire course (only -2 bpm between the first hour and the second, bearing in mind that there was more downhill on the second part).

Conclusion

I’ve noticed that a lot of trail runners don ‘t know how to manage their pace, often starting out too fast for their ability! This is quite normal, given that you don’t have many reference points when you start out on a trail, so it’s a bit of a mad dash in the first few minutes after the start.

My method, and thanks to the Stryd power sensor, makes it possible to adjust pacing to the athlete’s performance level. This helps to avoid certain pacing errors, and therefore to improve performance in the end!

As proof, at the shepherdess’ pace (after 30 minutes of racing), I was in 8th/9th position. Following my pacing, I hardly faltered, while overtaking all those who had made a kamikaze start. I even caught up with the third-placed runner at the top of the Moucherotte… and then got stuck in the mud trying to keep up with him on the descent (I strongly advise against Hoka Speed Instinct on muddy terrain ^^). I settled for a very respectable 4th place (3rd senior) behind the day’s rockets (see the rankings HERE), but above all satisfied with having followed my race plan!