Chris Horner's VAM on the Sierra Road climb in the 4th stage of the Tour of California was equal to 2015 m/h: on a 5 km climb at 10.6%, between an altitude of 50m and 580m, this means a power output of about 6.73w/kg.

Andy Schleck, second at the finish ahead of Leipheimer, yielded 1'15" with a VAM = 1870m/h, corresponding to 6.23 w/kg.

 

Alberto Contador's VAM on the hardest 6 km (10% average gradient) of the long Grossglockner climb was 1800 m/h, at an altitude between 1301m and 1908m, corresponding to 6.00 w/kg.

Only Rujano was able to resist to his acceleration, while the main rivals all had to give in about 1'30".

 

There is no doubt that Horner's performance was superlative, but we should make some observations in order to correctly evaluate these 2 efforts:

 

- Horner rode basically at sea level, whereas Contador was at an average altitude of 1600m; Alberto's performance therefore must be adjusted by +8%, getting up to 6.48 w/kg.

 

- Horner climbed the Sierra Road in 15'47", almost always out of the saddle, helped by a strong tailwind, while Contador climbed the 13 km of the Grossglockner in rainy and cold conditions, at the 13th stage of a tough Giro d' Italia.

 

Taking into account these differences, the average power output expressed by both cyclists could be considered very similar, at around 6.7 w/kg for efforts of about 15 minutes.