TdF 2013 - Part III
22 Jul 2013
Chris Froome's accelerations on the ramps of the Mont Ventoux greatly impressed both riders and commentators alike, more or less competent and serene in their assessments.
The adjectives, not always flattering, were pouring through, but only a few times, in my opinion, have been adequate to the actual performance.
Let's start by assessing the time to climb the last 15 km (1389m of altitude at 9%) of the ascent:
- Froome, 2013: 47'12 "- VAM = 1765 m / h - 6.08w/kg = 401W
- Armstrong, 2002: 48'33 "- VAM = 1718 m / h - 5.92w/kg = 438w
- Contador 2009: 48'57 "- VAM = 1702 m / h - 5.87w/kg = 364w
The climb is very exposed to highly variable winds and therefore performance comparisons over different years are always approximate, but we can hazard a guess that Froome has delivered a performance similar to or slightly higher than those of Armstrong and Contador, all in all in line with those developed by the best athletes in recent years.
What has caused a sensation and suspicion is the cadence held by Chris when climbing.
At 400w the ideal uphill cadence is between 90 and 95 RPM: Froome, when deeply engaged in the effort, is used to pedal on average over 100 RPM, with a cadence higher than that of Lance, who also developed higher average power outputs by about 40 watts (ideal cadence of 95-100 RPM).
But even more wonder have raised the pedaling cadences of 120-130 RPM expressed by Froome in the three short (15-20") accelerations that demolished the opponents.
If you want to accelerate violently on an uphill incline, even in a car, you need to downshift the gears and increase the number of "engine revs", in order to express the maximum power in a quick time.
Given the acceleration and speed (almost double that of the opponents) developed by Froome, I estimate an average power of about 700W for those 20", which correspond to an ideal cadence of 125 RPM. So the choice of Chris is the best, if you want to drop rivals off your wheel.
Of course such violent and repeated accelerations are possible only if the athlete is not already in "oxygen debt", displaying clear fitness superiority over the rivals who were sapped by the previous pace.
Particularly skeptical observers have noted that such high pedaling cadences require, for the same wattage, an increased consumption of oxygen due to the cost of "spinning the legs." It is a correct observation, considering that Froome is adopting cadences that are higher than those considered ideal for the power he generates.
With his "alien" physical morphology, very thin, with long, thin arms and legs, Chris compensates such higher cost by minimizing the weight of his rotating limbs.
The obvious muscle hypotrophy reduces internal friction and the probable decrease in strength is offset by the use of high pedaling cadences, which require, for the same wattage, a lower force peak at each push on the pedals.
The intake/supplementation (perfectly legal) of nitrates could further reduce the consumption of oxygen (Acta Physiol 2007; 191:59-66), improving mitochondrial efficiency (Cell Metabolism 2011; 13:149-159).
Even the rhythmic reclining of the head by Froome, interpreted by most as the continuing need to scrutinize the power meter on the handlebar, may be a breathing technique, already used by the British marathon runner Paula Radcliffe, to ensure an optimal pulmonary ventilation.
A few days ago, in Monte Carlo, another Englishman, Mo Farah, a specialist of the 5000 and 10000 meters, managed to improve the European record of 1500m, which was holding on for 16 years (Cacho, 1997): 3'28 "81, improving by more than 5 seconds his personal best.
Just like Froome, Farah, as well as for the outstanding performances, impresses for the ghastly, unhealthy thinness.
Achieved how...? Only with a particularly strict diet?
This is the question those who care about the physical and mental health of the athletes should try to answer to.