Giro 2011 - Etna Stage
It took 6 minutes 28 seconds for Alberto Contador to ride between km 6 and km 3 to the finish line, at the average speed of 28.1 km/h.
The VAM = 1821m/h on the average gradient of 6.5% required an average power output of 6.87 w/kg, equal to 426 watts assuming a body weight of 62 kg.
The ascent was affected by strong winds, therefore the expressed power was probably even higher, although it is quite difficult to quantify.
Furthermore, if we consider that the effort was done at above 1500m, where the partial pressure of oxygen is reduced by 19% compared to sea level, Alberto's performance over that distance is one of the best ones we've seen in the last few years.
In those 3 km, Contador gained 57" on his immediate chasers, that is 19" per km.
The group of with all the main rivals rode at a speed of 24.3 km/h, expressing a power that was 15.6% lower, equal to 5.79 w/kg.
Rujano was able to hold Contador's wheel for a bit, as drafting at such speeds would save him approximately 50 watts, expressing an average power of 6.06 w/kg, equal to 327w (assuming a body weight of 54 kg).
In the last 3 km of the stage, Alberto was not able to gain any more on the rivals, suggesting that the extraordinary performance of the previous 3 km was quite anaerobic, albeit supported by an exceptional aerobic power.