A wattage expert from TrainingPeaks compares Luke McKenzie’s ride in Kona to Michael Rogers’ Stage 16 Tour win.
by AJ Johnson
This article has been borrowed from ironman.com as it’s a fantastic example of how using power can help you evaluate and quantify your training.
Despite the busy IRONMAN weekend behind us, this weekend also saw the culmination of another feat of endurance: the Tour de France. Triathletes and cycling fans might be asking themselves what the differences are between a top professional triathlete riding 112 miles in Kona, and top professional cyclist winning a stage of the Tour de France. It’s hard to compare, but we took a look at the Quarq data from Luke McKenzie’s blazing 4:21 ride in Kona (the second fastest of the day), and compared that to the SRM data from Michael Rogers’ 6:03 ride to win Stage 16 of this year’s Tour de France to see where they differ and what they have in common.
When it comes to power, there are three key metrics, Average Power (AP), Normalized Power (NP) and watts per kilogram (w/kg). AP is simply the mathematical average of the numbers. NP uses an algorithm to give the true physiological cost of your effort. Using w/kg, you can compare riders’ wattages on an apples-to-apples basis. AP, NP and w/kg. are also used to calculate other key metrics.
Before diving into the numbers, it’s important to understand some differences in their challenges. After his ride, McKenzie had to run a marathon, so he needed to keep some energy in reserve. Rogers was racing for a victory at the end of the stage, with no running, so he could “leave it all out there” on the bike. However, Rogers had already ridden 16 stages and a total of 1,775 miles before his victory. For McKenzie, drafting is illegal—Kona is a 112-mile individual time trial. Rogers, on the other hand, is encouraged to draft. He did get in a breakaway early with 20 other riders, so there were times when he didn’t have the benefit of others. Finally, McKenzie climbed 5,459 feet, while Rogers had to climb some of the toughest mountains in the Tour, gaining 9,594 feet over 145 miles.
The most impressive aspect of Rogers’ data is his w/kg power output. Rogers was able to hold 4.20 w/kg for over six hours to McKenzie’s 3.87 w/kg for 4:21. Again, McKenzie still had to run after his effort—and he ran a fantastic 2:57 marathon—but Rogers had already pedaled 1,775 miles in just 16 stages. For Rogers to have this type of power output after so many consecutive days of racing is nothing short of amazing.
For McKenzie, the goal is to produce power evenly over 112 miles. The Variability Index (VI) shows how smooth or variable a rider’s power output was. This is calculated by dividing NP by the AP. A key to a strong IRONMAN bike is to have a VI of 1.05 or less, and McKenzie’s VI is 1.05 (295 / 281 = 1.05). Rogers is not concerned with VI in any way. In cycling, you have to respond to the attacks of the other rider(s), and then beat them to the line, there’s no run afterwards to catch anyone. This often leads to a surge and recover type of racing, which leads to a higher VI. Rogers’ NP was 346 watts and his AP was 296 watts, giving him a VI of 1.17 (actually fairly low for this type of racing). For most stages, Rogers’ VI was 1.25 or higher. If McKenzie had Rogers’ VI, he’d be cooked coming off the bike and would struggle through the run. If Rogers’ had McKenzie’s VI, he’d be at the back of the race. In short, each man executed well for their needs.
Rogers was in a small breakaway group from the beginning, which had to ride hard to stay away. His peak one-hour power was an amazing 387 watts, or 5.35 w/kg. Compare that to McKenzie, whose peak one-hour power in Kona was 306 watts, or 4.22w/kg. Shorter, harder efforts show an even bigger contrast. For Rogers to win, he had to attack his breakaway companions. After riding for 147 miles and with only three miles to go, he put in his race winning move. Rogers pushed 377 watts, or 5.21w/kg, and averaged 31 mph for 4:35 to drop the two riders left and cross the line first. McKenzie has no need to put in an effort that hard as it would burn up his glycogen and leave him with nothing left for the run. The fact that his peak 5 minute power is 344 watts, 4.74w/kg, is a testament to smart racing.
They do have some aspects in common. First is their Intensity Factor (IF). IF is a measure of how hard a ride was compared to the athlete’s peak one-hour output, or Functional Threshold Power. For McKenzie, his IF was .81, meaning he rode at 81 percent of what he could hold for one hour for over four hours. Rogers’ IF was .82 for the over six-hour ride. Granted, Rogers held his for two more hours than McKenzie, but if he didn’t have to stop and run at the 112 mile mark, McKenzie could likely hold that intensity for another two hours on the bike.
Another commonality is the fact that both men were burning approximately 1,000 calories per hour during their ride. Rogers expended 6828 calories over his 6:24:29 ride while McKenzie burned through 4411 calories over 4:21:27.
As we can see, it’s tough to compare these files as they aren’t apples to apples. McKenzie had to run, and run fast for 26.2 miles, off the bike while Rogers had a tremendous amount of fatigue before his ride. One rider needed to be even while the other had to attack, recover and repeat. Really, the takeaway is that both men are extremely talented at what they do. The power they produce and they way they execute their strategy to accomplish their goal makes them top professionals in their sport.
To check out more Tour de France and Kona files follow the links below.
AJ Johnson is the Editor of the TrainingPeaks blog.