How Important is Anaerobic Energy in Cycling? Part 2
Friday, January 4, 2013 at 2:51PM 
We all know we use a mix of aerobic and anaerobic energy in cycling...and sometimes it can feel like our anaerobic efforts (and thus anaerobic training) are more important. In part 1 of this series, we defined anaerobic vs. aerobic phsyiological energy systems and analyzed how much a stage from the Tour de France required use of our anaerobic systems. In part two, we'll take a look at pro race files through the lens of Power Zones to see just how anaerobic or aerobic our sport really is.
To do this, we use the TrainingPeaks Power by Zones chart. The Power by Zones chart provides the percent of time pedaling in all power ranges during a training ride or race.
The seven power zones used to analyze each race file are from Andrew Coggan’s Power Training Levels. All levels are a percentage of Lactate Threshold (LT) power. The main source of energy for each training zone has been established using a percent of each rider’s maximal power outputs, compared to the primary energy system stressed on the “Training Specific Energy Systems” chart from part 1.
For this article, and slightly different than how Dr. Coggan calculates each training zone, I placed a numerical value for Zone 7 to further define anaerobic efforts within a race. Zone 7 is set to display power outputs greater than 226% of threshold power - equivalent to approximately 75-100% of each rider’s maximum power output range and mainly anaerobic (refer to article one for explanation).
Let’s analyze and compare two disciplines of road racing and two disciplines of mountain bike racing to show how much aerobic and anaerobic metabolism plays a role in each race.
Road Racing Files
Greg Henderson’s 2012 Tour de France Stage 4: Abbeville - Rouen 214.5km – Duration 5.5 hours
Greg Henderson’s 2011 Amgen Tour of California Stage 6: 24km Time Trial – Duration 33 minutes
As you can see by looking at Greg Henderson's (Lotto-Belisol) power data, 93% of the 214.5km stage and 83% of the time trial race took place between zones 1-4, showing that both race efforts relied heavily on aerobic metabolism. This is not to say that anaerobic metabolism does not play a role, it definitely does. 38% of the TT effort is spent between zones 4-6, compared to 12% for the 214.5km stage, showing that the TT effort relies on more anaerobic energy than a long distance road race but the majority of the race is still mainly aerobic.
It is important to note that Greg spent 29 seconds in Zone 7 during the 214.5km stage race, within the final minute of the race sprinting to the finish line. That represents .001% of the race so it is not displayed but it was a very important part of the race, if not the most important. He also spent zero percent of time in zone seven during the TT effort.
Mountain Bike Racing Files
Jeremiah Bishop's 2012 Cohutta 100 mile mountain bike race – Duration 7 hours
Jeremiah Bishop's 2011 Fontana City National - Pro XC – Duration 2 hours
When looking at both mountain bike races from Jeremiah Bishop, we see that 92% of the 100-mile Cohutta race and 76% of the Pro XC race was spent between Zones 1-4, showing that both of these race efforts relied heavily on aerobic metabolism, similar to both road race examples. You can see that for the 100-mile mountain bike race, 58% of it was spent between Zones 2-4 making this race effort the most aerobic effort of all the races. But on the flip side, 23% of the Pro XC race was spent in Zones 5-6 making this race the most reliant on anaerobic energy of all the race disciplines.
It is also important to note that Jeremiah spent four seconds at the Cohutta race and seven seconds at Fontana race in zone seven.
In conclusion, it is important to realize the large role aerobic metabolism plays in most, if not all, cycling disciplines. At the same time, it is also important to realize how much of certain intensity is needed to do well for each specific type of race. To do well in a XC mountain bike race, a well-timed focus to improve VO2 max and anaerobic capacity efforts needs to take place. If it is a road time trial race, a large focus needs to be placed on gaining endurance and power in zones 3 and 4. But underlying even the hardest efforts on the bike is the role of aerobic energy. It is not always about how hard you can go, but how often you can go hard – that takes aerobic endurance.
Don't miss: How Important is Anaerobic Energy in Cycling? Part 1.
Mike Schultz brings more than 10 years of racing and training experience from national endurance and ultra endurance events, mountain bike stage races, and 24 hour solo cycling events. Mike is the head coach and founder of Highland Training. He is certified with the National Strength and Conditioning Association (NSCA) as a Strength and Conditioning Specialist (CSCS), Personal Trainer and as a USA Cycling Certified Coach. He continues to compete in endurance and ultra endurance events on a regional and national level to further study the science behind sports specific training and practice what he preaches. Mike resides in the Laurel Highlands, Pennsylvania, where he coaches and trains full time and year round. Follow Mike on Twitter @Highland_Mike.
Reader Comments (7)
Does the analysis of the hill stages suggest similar energy system contributions?
This was a very interesting article, however it would be interesting to see the data presented from riders much slower in these same events as a comparison. Also as these riders used are at an elite level, it may be interesting to see differences between them and the efforts of those less conditioned to cope with such high intensities such as semi-pro and non-pro riders. I only mention this as the athletes used will have such highly tuned and conditioned systems in order for them to rely on more efficient muscle fibers (type I) and oxidative capacities while also possessing highly tuned thermoregulery systems thus allowing more efficient energy supply, distribution and production. By this, what I mean is would the data and the energy system reliance be similar in lesser conditioned riders. I only mention this I imagine the majority of readers may not be at an elite level and therefore this article may provide some misconception to those wishing to improve their performance through training, in that the article suggests aerobic training would produce better results, however as you will know yourself, training at and near peak outputs such as anaerobic threshold and lactate threshold produce significant results in improving aerobic capacities significantly faster than steady state aerobic training due to the body being stressed with such high demands and having to adapt to these stresses in order to try and regain some level of homeostasis. Besides this, the data presented was interesting, although it would be interesting to know if the power meters used are the same as different models have been found to over and under estimate outputs in correlation to that of the SRM system used as the gold standard.
Jason,
Great question and yes. Jeremiah's 100 mile Cohutta race file shown above is a good example of a file with a lot of climbing with about 12,000 vertical feet of elevation gain for the day.
Mike
Philip,
You also present great questions. It would be interesting to analyze race day power files of all abilities, from amateur to elite for the same event. This article focused on comparing four different styles of cycling racing to show how aerobic the sport of cycling is and the best way to do that was to compare files from elite riders who can produce similar power outputs.
I agree, elite athletes are highly conditioned and can produce greater power outputs while working aerobically compared to non elite athletes. Elite athletes can also work anaerobically more often due to the size of their aerobic engine.
Non elite riders are going to be able to train and race within the same energy systems but with less power to weight ratio and for less durations compared to an elite rider. It is the goal of the non elite racer to recognize strength and weaknesses towards their specific goals and work on those weaknesses to improve. The files above are great examples of what type of energy it takes to do well in a specific race discipline.
Even when you are working at your threshold levels, you are still working with a large amount of aerobic energy (This is shown in Article 1). You are correct that by working at or near your threshold you produce significant results. The only problem with working at or near your threshold power is that it is hard to train there all the time. Training there too often can also lead to an over trained state.
This article is not to suggest that you can produce better results through aerobic training, it is to show how important training aerobically is to the sport of cycling. Depending on your goals, a well timed use of threshold training will produce great results. But keep in mind the bigger your aerobic engine is, the more often you will be able to train at and near your threshold when it is time.
Hope this helps.
Mike
It would be interesting to compare a criterium and a cross race to the other types.
Mike
What can you give as an example of "working in" zone 5&6 workouts after a winter base leading into first race of the season.
I am sport class MTB (1.5hr races). Approx.5-7hrs a week on bike. Usually 3 dedicated workouts. 48 hrs between workouts.
Thanks in advance
Scott
Scott,
To work zones 5&6 it requires super hard efforts from 20 seconds to 5-6 minutes. You could figure out your current power ranges and then target zone 6 with all out 20-30 second, up to 1-2 minute efforts, and zone 5 with 5-6 minute efforts. For short efforts under a minute, I always recommend to not look at power numbers and just work a super hard effort. Looking down at the handlebars, and not focusing ahead can take away power from a short effort like that, especially when standing. But for your 5-6 minute efforts, you can figure out your zone 5 power ranges and then work those ranges, or beyond those ranges for the duration if your feeling stronger. You could work short efforts one day, longer efforts another or mix them together for a day to work it all. Another way to work a mix of efforts like this is to go on a competitive group ride.
Hope that helps.
Mike