Chamrousse Trail analysis
The sun was out on the Belledonne massif at 8am on Saturday July 7, and I was there for my first trail in the TrainingSharp colors!
The Chamrousse course promised to be quite technical, with a string of stony singles, a mountainous profile (1850 D+ over 29 kilometers), and an absolutely splendid setting. It was the perfect introduction to trail running for me.
Figure 1: Profile of the Sportif course – 29 km / 1850m D+. The 4 climbs are identified.
The day’s winner, Jérémy GUILLOTEAU , won the race in 3h10:26 at an average speed of 9.14 km/h, a far cry from the average speeds of over 11-12 km/h seen at the French Trail Short Championships. This is due to the technical nature of the terrain, the altitude (1136-2248m) and the profile of the course (very few rolling sections). It’s difficult to make comparisons between trails, but we can guess that the level of a French Trail is higher than at Chamrousse (for the time being ;)).
I finished 2nd, +12:26 behind Jérémy, in a race in which I tried to manage as best I could an effort that was unfamiliar to me, being rather used to OC and its more intense, shorter, less traumatic efforts. I quickly realized that my muscular potential to withstand the shocks on the descents was limited – partly because of my choice of shoes (Innov8 XTalon 212), and partly because of my lack of specific training. Race management quickly boiled down to: “take it easy downhill so as not to destroy myself” and “manage my effort on the climbs so as not to burn out”. This management paid off, however, as I was able to take second place ( 😉 from cross-country runner Thibault MONDON), still having some gas in the final kilometers.
Let’s take a quick look at the data from the Stryd power sensor to see how it can help you manage your pacing.
The average power of 214 W (68% of CP) reflects the technical nature of the trail, or my lack of trail experience (take your pick).
- Now, let’s focus on the climbs, which I’ve divided into 4 main ones:
- Ascent to Lac Achard/Col de l’Infernet: fairly common but technical terrain, so progress is slow.
- Ascent to La Botte: the steepest part of the route, dré dans l’pentu! A lot of walking.
- Lac Longet climb: Same type of climb as the first.
- Ascent to La Grande Aiguille: The big climb of the course, with alternating running/walking sections. The decisive moment of the race!
Below are the data I collected, heart rate and power being the most interesting to discover:
The first climb is naturally the most intense, at 80% CP. There’s a dip in intensity on the second climb, which is completed on foot (average gradient 56%). The drop in intensity is noticeable with a reduction in heart rate of 4 bpm / 18 W, and on the ground, it’s Jérémy and Thibault who easily take the distance from me. So I’m left alone to try and maintain a decent pace, but the numbers don’t lie: I’ve clearly fallen asleep on this section.
Indeed, the 3rd climb, the shortest, was also the least intense period, at 72% CP and 154 bpm average (85% FCM), probably because I was looking at the scenery a little too much.
The last climb was my last chance to get back to the front, but fatigue made itself felt, and although I was initially able to maintain the recommended 250 W, I naturally weakened, without collapsing either. However, the averages of 234 W and 156 bpm reflect both my state of fatigue and my ability to manage with the strength I had left.
This data shows me the progress I need to make if I’m to compete with the good runners. The lower-than-expected intensity (72-74% CP instead of 80% uphill) shows my lack of endurance over 3 hours.
There are several reasons for this:
- Lack of motivation: no particular goal, so not really in a competitive spirit.
- Lack of specific preparation (particularly on the musculo-tendinous and mental aspects): Preparation focused on the French CO Championships two weeks earlier, where I came 2nd behind Vincent Coupat.
- Residual fatigue: exhausting session (with heat and dehydration) 3 days before the race.
- Poor nutrition: 1.5 L of water, 0.5 L of Coke, 1 gel, a little salt and gingerbread at the feed stations. So not enough carbohydrates to keep up with the planned intensity.
- Questionable choice of shoes: I preferred lightness to cushioning, as I’ve always been accustomed to running in lightweight shoes (200-250g) to preserve the dynamic aspect of the stride and encourage the foot to work hard. However, over a relatively long distance like this one, with a lot of downhill sections, a good cushioning seems preferable to minimize muscle breakage and keep a correct level of commitment throughout.
- Altitude tolerance: no prior acclimatization. However, you should be aware that altitude (1800m – 2200m) reduces performance by around 5-10% compared with the plain.
- Technical trails: My energy costs may not be optimal on technical trails.
This type of analysis is essential after each trail run, in order to draw up work prospects and identify areas for improvement that will be put to good use at future events. Here’s an example of what’s been put in place for my athletes!
A big thank you to the smiling volunteers who made the event such a success, and see you next year!
If you’re interested, I’ll present you with a microcycle based on this analysis to help you perform better on your next trail.
Stay tuned!
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