As I have stated, the question I am asking is, "Was Luke McKenzie's change to 90+ rpms on the bike, a big reason for his dramatic improvement in Kona?"
Of course, there are many other factors that contribute to a race, and proper pacing is probably one of the biggest. So let's look and see how the pacing went in these races, and if that played a role in the differences in the placings for Luke in Kona.
How can we assess pacing? In Kona, perhaps more than any other Ironman, the first hour matters a lot. The first hour on the bike matters in all pro Ironman races, but in Kona it includes the town loop, with climbs on Kuikini and Palani, packed with screaming fans, and the desire to make the lead pack onto the Queen K, given the legal drafting benefit, and the mental push of having the athletes around you to keep the pace high.
Considering Luke has always been a top swimmer, he comes out with the lead group and tends to stay with them early on the bike and throughout much of the race. The first hour of his bike will bring him well past the 25 mile mark, meaning they are traveling over 25 mph! In fact, the range of distance covered in 2011-2013 through the first hour is 26.1-27.8 miles! That's fast, and with the early surges and climbs in the town, you can bet there isn't much room for error. So I was curious, did Luke just pace himself better in 2013, than in 2012 and 2011?
Variability Index, (VI), is a measurement in TrainingPeaks which helps us see how much variance there was in the power output of the athlete. It is basically average power divided by normalized power. If the athlete rode perfectly steady, VI would be 1.0, meaning normalized and average power would be nearly identical. If it is 1.12, that means the power varied 12%. A typical pro variance is about 1.05 or less for an entire Ironman bike.
So let's isolate the first hour of the bike, and see how volatile the pace was, with surges up the hills, and staying with the pack. (Click on all images to enlarge)
You can see that usually the pace is quite varied early, and is much more settled down in the last hour. What is really interesting here is that I was expecting to see that in Luke's best performances, he likely paced himself better, limiting the surges. But what we actually see is the exact opposite! Luke's two biggest VI's were in his two best performances in Kona! His worst performance of the three, 2012, was a significantly lower VI and more steady, much better paced, in the first hour.
So what was different about these three samples, that sets 2012 apart in terms of best pacing, but worst performance? Let's review the basic data from the three rides again.
In the above chart, you can actually see that his OVERALL VI was higher in 2012. But don't forget, it also was his largest power fade of the three years. See the next chart. (Click to enlarge)
When your power output drops nearly 30% from the start, and you've paced yourself without surges extremely well at the beginning, the effort to produce the watts is too much to maintain. So was it fitness, or the execution of the ride, in terms of cadence vs. force on the pedals?
Remember, his FTP in 2012 was 360, same as 2013, and he actually produces a lower IF, and lower TSS in 2012 than 2013. Usually, that means less taxing or stress on the body, which would signal a better opportunity to run well off the bike. But that didn't happen in 2012 at all.
Part of pacing is also knowing that the intensity you're riding at is correct, not just surges. So let's compare Luke's hour 1 VI in Kona, with the IF from that first hour, to see if he just rode too hard, even if not varied.
Here you can see he actually had his highest IF in 2012, in that first hour, but only 4 tenths of a percent more than 2011. And 2011 was MUCH MORE volatile in that first hour. In 2013, he was rather volatile, but the actual intensity of the watts relative to his FTP was lower than the prior 2 years by about 4%.
(Just for reference, the first hour of 2013 World Champion Fredrik Van Lierde was 1.05 VI, and 0.79 IF).
Lastly, let's look at how he rode those watts, relative to force/cadence, with a quadrant analysis, isolating just the first hour of the bike each year, and then compare that with the QA breakdown for the entire race.
QA Hour 1
QA Entire Race
Here we can see that Luke actually increased his Q2% in that first hour in 2011 and 2012, compared with how he rode the rest of the race. Remember, Q2 is high force, low cadence, below 90 rpms. But in 2012, he spent a significant more amount of time in Q2, than 2011. In 2013, he actually spent less percentage of time in Q2 during the volatile first hour than he spent the rest of race. He even spent more Q4 time spinning over 90, in that first hour, than the rest of the race, percentage wise. He spent the same percentage of time in Q1 in 2013, in the first hour, as he did the entire race.
- In the most volatile hour of the 2013 race, Luke spent over 76% of the time over 90 rpms, which was more than he actually did for the whole race
- Luke's 2012 first hour of racing, his lowest cadence year, was actually less volatile the first hour than 2011 and 2013
- Luke's 2012 first hour was about the same IF as in 2011, but about 4% higher than 2013
- Luke's Q2 time in the first hour of 2012 was significantly higher than the other years, being more than twice 2011, and nearly 10 times more than in 2013
- Luke's biggest power and cadence fade came in 2012, despite the lower volatility in the first hour, and similar IF to his excellent 2011 performance
Basically, from this data I think we can say pacing made very little difference, as his small VI and similar IF early in the ride don't prove poor pacing on his part. (Although his IF in hour 1 was lowest in 2013, and 4% might have made the difference).
So what was the big difference in the performance? Was it that he was better able to tolerate the volatility based on his higher cadence he rode in 2011 and 2013 in that hour, compared with 2012? Did his mashing, high Q2 time, catch-up with him and sap the run out of his legs?
Yes, the sample size here is very small, but these are questions which coaches and Ironman athletes need to ask themselves.