Tom Dumoulin in Grand Tours (van Erp et al 2019)

Some of the best pro cycling research in the last few years has come out of Team Sunweb thanks to sports scientists Teun van Erp and Dajo Sanders. They have had access to Sunweb’s power files for several seasons of racing and have written several detailed analyses of the differences between men’s and women’s racing, the relationships between different training load measures across different stage types, the influence of race category and results on intensity, and several others.

The most interesting work was done by van Erp in collaboration with three other researchers, and was published in November 2019 in Medicine and science in sports and exercise as Load, Intensity, and Performance Characteristics in Multiple Grand Tours. The pdf can be accessed at that link.

Their work analyzes four grand tour performances by Tom Dumoulin where he was the GC leader for Sunweb/Giant-Alpecin in the 2015 Vuelta, 2017 Giro, 2018 Giro, and 2018 TDF. As the paper notes, Dumoulin finished 6th, 1st, 2nd, and 2nd in those tours and won at least a stage in each. Not included in the analysis were three other grand tours in the time period where he DNF’d as the focus was on his performance while contending for GC throughout.

Their data set was Dumoulin’s power data on the finishing climbs throughout the Tours. In this case, they had 33 climbs ranging from short efforts like Mur de Bretagne in Stage 6 2018 TDF to longer efforts like Mount Etna in the Giro. They supplemented the power files with information about the climbs (gradient, distance) and stage conditions (temperature, altitude climbed prior to final climb).

The main findings were that the three different grand tours had broadly similar requirements to win in terms of load and intensity characteristics. The power requirements over 33 final climbs in those tours averaged 5.9 watts/kg +/- 0.6. And those power outputs were impacted significantly by the duration of the climb and the amount of climbing prior to the climb on the stage.

Ross Tucker and others in less formal analyses have shown before that watts/kg in the high 5s/low 6s are required to contend for grand tours in the mountains, so it is great to see that replicated with actual power data from a World Tour team. Ross quotes the work of twitter climb timing expert Ammattipyoraily in a 2015 article here showing estimated watts/kg for Tour winners using Michele Ferrari’s equation; he showed Armstrong averaging 5.92 watts/kg or higher in his last six Tour wins, with more modern winners like Contador, Nibali, Wiggins, and Froome in the 5.87-6.07 watts/kg range.

Mike Puchowicz has also posted graphs of relative power output for the top contenders in 2013 and 2014 TDFs here. You can dig into Ross’s archives on the Tour analysis here and read Mike’s work at Veloclinic.

Returning to the paper, the most interesting part of this work is when they analyze a range of variables and how they impact the power output on a climb. Obviously I would love to see this with more than one rider, but their results fit the smell test and give us some coefficients. Their three factors influencing power output on final climbs are:

  1. duration of the climb (length is negatively associated with power output)
  2. gradient of the climb (steepness is positively associated with power output)
  3. total elevation gain (TEG) before mountain (a lot of preliminary climbing is negatively associated with power output)

The log duration in minutes of climb is such that a 15 minute effort is ridden at 0.8 watts/kg higher than a 45 minute effort. The gradient (in %) is such that a 5% climb is ridden at -0.6 watts/kg lower than a 10% climb. And the total elevation gain is such that a climb after a comparatively flat stage before a climb (TEG of 1000 meters) is ridden at about 0.45 watts/kg higher than a climb after a comparatively mountainous stage before a climb (TEG of 3000 meters).

This certainly fits with what you would assume; a short, steep climb at the end of a flatter stage (think the typical wall finish in a Vuelta) would be ridden at a high watts/kg, while a long, grinding alpine climb at the end of a tougher climbing day would be ridden at lower watts/kg.

They also show Dumoulin’s maximum power profile over each race, which shows 20 minutes efforts of 6.0-6.2 watts/kg and 60 minute efforts of 5.1-5.6 watts/kg across the four races (page 11). They also plot each of the 33 finishing climbs with the climb duration (X axis) and watts/kg (Y axis) to show his relative power output (page 12). He likely peaked in these four races in stage 14 of the 2018 Giro on Mount Zoncolan where he was bang-on 6.0 watts/kg for 40 minutes in finishing 5th on the stage.

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