Tour stage 6: Power-to-weight ratio

Featured athletes: Danny Pate, Magnus Backstedt

Provided courtesy of Saris Cycling Group

As the terrain begins to go upward, as it did in Stage 6’s uphill finsh, it is important for the riders to be able to maintain a high watts-per-kg or power-to-weight ratio. Watts per kilogram is power output normalized to body weight. The reason we like to normalize power to body weight is that going up a hill, two people might be going the exact same speed, but if they aren’t the same size, they won’t be putting out the same power.

Today on the stage to Super Besse, we saw Christian Vande Velde attack with 5 km to go. Allen reports:
From the team’s perspective, the final KM’s of the stage were hard. Christian had good legs today and went for the attack. It was a planned attack to either 1) catch people off guard and go for a great win, or 2) string it out and set it up for David Millar. So it was pre-mediated.

The team’s top GC guys like Christian, David, and Ryder maintained 5.5 to 6.0 watts per kg on the last climb, with each of their last 5 minutes in the range of 6.0 to 6.5 watts per kg.

On the other hand, after doing work for the team early on, Danny and Magnus cruised the last climb at grupetto pace which was 4.0 watts per kg for the last 40 minutes of climb. These two riders are very different in terms of size: Magnus weighing in at 94 kg on his 6′4″ frame and Danny weighing 70.3 kg on his 6′ frame. If we take a look at the two riders power files for the last climb of the race, they look quite similar:

Danny Pate:

Magnus Backstedt:

For the 40-minute climb, Backstedt had an average wattage of 346 white Pate averaged 286 watts. Backstedt’s watts were quite a big higher than Pate’s. However, if we calculate the power-to-weight ratio for the two riders, we get 3.68 watts per kg for Backstedt and 4.09 average watts for Pate. So we can see why watts per kg becomes a more relevant number for climbing.