DECODING MY MARMOTTE FILE
Putting theory into practice, Jim
Cotton analyses his data from the 2018 Marmotte, with help from numbercrunching coach Stephen Gallagher
Step 1: The basics Moving time: 7:03:04 Weighted average power: 214W Average HR: 140bpm Training load: 506 Relative effort: 776 Step 2: Pacing and sustainability Bracketed areas on the file indicate the key areas to assess consistency of effort — the four huge climbs. To survive a huge day like La Marmotte, it’s key to take all four cols at a reasonably consistent and sustainable pace.
“Your heart rate and power lines were quite consistent throughout all the climbs,” Gallagher reassures me, “and your endurance is good — the cardiac drift isn’t too bad. Look at the segments: 228W and 147bpm on the Glandon, and 215W and 149bpm on the Alpe d’huez. Losing only 13W and gaining 2bpm is actually pretty good.”
For a brief moment, I pat myself on the back — but then Gallagher moves on to the negatives.
My ride data reveals periods of rashness and over-exertion; the first circle shows a rapid heat rate increase at the top of the Glandon, indicating that I pushed too hard to reach the neutralised descent. Compare this, for example, to the relatively slow rise in heart rate on the Télégraphe — a more steadily paced climb. The second circle shows elevated heart rate in the valley section. When I should have been sitting pretty in the wheels, I worked hard to drive a group, and this marks an unnecessary burning of a match that I should have saved for the final hour. Step 3: Other factors
You’ll notice a decline in power on the Galibier, where my output drops despite my heart rate staying high (third circle). At this point, the altitude of a climb topping out at 2,600m is playing its part. “With the thin air and inability to translate effort into power, your output drops. However, there’s only around a 20W drop in your power from the start to the end of the climb, showing you tolerate altitude well,” remarks Gallagher.
The decline in my power on Alpe d’huez can be interpreted alongside the heart rate line (fourth circle). Gallagher explains that here, despite the rising temperature indicated at the bottom of the graph, the drop in power isn’t due to dehydration.
“Dehydration would have been illustrated by decreasing power and increasing heart rate. Instead, the way in which your heart rate line and power line decline together suggests muscular fatigue: you’ve simply started to peter out.” Step 4: Broader context
A training load of 506, and relative effort of 776, is huge, and clearly represents the duration and intensity of the ride. A load such as this requires significant recovery time — I felt incapable of doing much for many days after!
Before heading back for La Marmotte 2019, Gallagher advises some Strava-stalking: “Find those who did better than you this year, pick out some key moments from the ride, and see what they were doing.”