from Allen Lim, PhD
"Arrive Alive." That's been the tag line for the first two days here at the Tour – arrive alive. Despite Julian Dean getting caught up in a crash with a few kilometers to go today, everyone has been keeping that line in their heads, staying out of trouble, and finishing the last two stages feeling fit and relaxed.
One of the most interesting things to me over the last two days has been the amount of climbing the guys are accumulating over the very rolling terrain and the resulting power profiles. Yesterday, the guys did over 8000 feet of climbing, and today they did just over 6000 feet of climbing. In the mountain stages, we'll see totals in the 10,000 to 15,000 foot range, so the last two days as opening stages weren't trivial, especially since there weren't any really long climbs to speak of, just a lot of up and down. As a result, the guys had some big differentials between their overall average power that includes time not pedaling and their average power when just pedaling (excluding time at zero watts).
In a typical race, we see differences in the 20 to 30 watt range, between the overall versus pedaling power output. But in the last two stages, we've been seeing 50 to 80 watt differences, with the guys accumulating on average 50 to 70 minutes of "float" time (time at zero watts) in each stage. What that means, is the guys have either been totally on the gas or totally off the gas. If you've ever driven you're car this way, you know it's an inefficient way to burn fuel and hard on the engine. So in a nutshell, the last two days have been harder than average.
That said, the guys all feel better than average and have been coming on the bus looking a whole lot better than they did at the Giro. So in my mind it's been a good start. The last two days, we've also been spending a lot of time talking about looking after one another over the next 3 weeks. The Tour in so many ways is a hostile event, and we all know the only way we're going to get through this is to watch out for one another and to stay cohesive as a team. With that in mind, I give the guys a daily report with everyone's data for the previous stage - average power, peak power for different time spans, heart rate, etc - I haven't been censoring any of the data between the guys. Instead, I've been just putting everyone's numbers on one report for everyone to analyze and compare.
What's interesting to me is that the effect has been pretty positive, with riders contributing and commenting one another's data, looking for ways to maximize one another's potential. On the technical side, however, comparing numbers between guys isn't that cut and dry. Because all of the guys have different body weights, heights, and values for aerodynamic drag, you can't always directly compare one rider's power output and workload with another rider's. With that in mind, we end up talking about power in terms of power to weight a lot more than in absolute terms.
For most of the guys we've got at the Tour an average day on the bike will be somewhere in the 3 to 4 watt per kg range including zeros. If you don't include zeros, most of our guys will have a power output when pedaling of about 3.5 to 4.5 watts per kg depending on the course. In general, a hard effort for our riders starts at about 4 watts per kg (that's 280 watts for a 70 kg rider) – a power output they can hold for well over 3 hours if pressed and if fed properly (meaning a lot). At about 5 watts per kg, things start to feel very hard. It's the speed that the main field tends to roll at while climbing and a power output that our guys can hold for up to 1.5 hrs. At about 6 watts per kg, the leaders are off the front on the big climbs. This is a power output that the best climbers on our team can hold for 20 to 30 minutes. At this power and this time frame, we're talking an all out effort. And if sustained repeatedly over 3 to 4 major passes on a 5 to 6 hour mountain day, we're talking a Grand Tour winner.
Using the average power to weight for the day, we can also normalize the total work (Kjoules) to a standard body weight. In our case, we normalize everything to 70 kilograms by taking their average power to weight and multiplying it by 70 to get a normalized power output. It helps us compare a guy like Trent Lowe who is under 130 lbs with a guy like Magnus Backstedt who is over 180 lbs, allowing us to see who is doing relatively more or less work. In yesterday's stage for example, Magnus did an absolute workload of 4973 Kilojoules at an average power output of 295 Watts, while Trent did an absolute workload of 3232 Kilojoules at an average power output of 195 Watts. Because of their difference in size, they require vastly different amounts of energy to do the exact same course. But when we normalize to a standard body weight, we get a workload of 3855 Kjoules for Magnus and 3901 Kjoules for Trent. From this perspective, they both did about the same work.
This was also the case for our guys today, with each guy doing a normalized workload of about 3000 Kjoules. What was interesting about today's data though was some difference between our protected riders like David and some of our newer riders. David had the lowest normalized workload today, while Trent actually had the highest. Part of it was that as our smallest rider, Trent had to do much more work to fight against the winds today than our bigger riders who have relatively less surface area for their mass. But part of that difference between guys may also be experience and position, as our Tour vets seem to be doing less relative work compared to our rookies.
Seeing this data, our intent for tomorrow is to equalize things a bit more. As the Tour progresses, however, we'll naturally see bigger differences between the riders as roles become more defined and our super domestiques start accumulating more total work protecting the GC riders, while those GC riders start showing more time at peak power outputs above 5 watts per kg. Until then, we'll keep on looking after one another, take every opportunity that comes our way, and stay focused on arriving alive and well in Paris.