Toolbox: Building VO2max Capacity
Cycling is an aerobic sport. Sure, it’s nice to have a strong sprint, but climbing with the pack, riding in the break, and getting to the finish line with the leaders are all crucial to success. How do we go about building the aerobic engine and VO2max beyond simple “endurance” rides?
The challenge is that when we bring up the idea of “aerobic” in cycling, many people immediately think endurance training or some form of long, slow distance riding, but we want to focus specifically on improving your maximal aerobic power or VO2max.
VO2max represents the maximum amount of oxygen that can be utilized by the body. There are two components to VO2max: the heart’s ability to pump blood via stroke volume and heart rate (central) and the muscles’ ability to extract and use that oxygen (peripheral).
VO2max interval training primarily affects stroke and pump volume (central), while providing some ancillary benefits to oxygen extraction and utilization (peripheral), which is best achieved through more steady-state efforts.
VO2max Interval Training Basis
An athlete working at VO2max can typically sustain the effort for 5-8 minutes at best. Going as hard as you can for 5-8 minutes is exhausting, and repeating such an effort would be unrealistic. But if you break down that effort into 3- to 4-minute efforts separated by periods of active rest, the athlete can typically repeat it for 18-20 minutes at the same pace, significantly increasing the total volume of work at VO2max and building VO2max capacity.
Full gas prologue effort from Damien Gaudin in the Tour de Luxembourg
The Role of Specificity
VO2max plays a specific role in endurance sports. Simply put, it is the size of your aerobic engine, dictating how hard you can go for how long.
By training at or near Vo2max, you can increase your VO2max capacity, and maybe even increase the actual power you put out when riding at or near VO2 max. But most importantly, you can lift your threshold. Why? VO2max is the ultimate cap to an athlete’s threshold (FTP, MLSS, LT2), and threshold is in general the greatest indicator of endurance sport success.
Once an athlete has completed enough steady-state work to raise aerobic power and threshold to the highest level possible, VO2max intervals are the way to continue that growth. Specifically targeting power at VO2max increases will not only give your FTP more room to grow, but will better prepare you for the physiological and psychological demands of racing.
To demonstrate the effect of VO2max training on mFTP, let’s take a look at the growth of an athlete’s modeled VO2max and increase in mFTP. The chart below is an illustration of the way small gains in VO2max translate to larger gains in FTP, as long as correct training methodologies are used.
The Role of Overload
Once you begin to complete VO2max intervals, it is crucial to focus on overload. VO2max work will create rapid response; typically most adaptation happens in 3-4 weeks. To maximize this window of rapid response, you must continue to increase the overload in a progressive fashion, tracking total time at VO2max. Build from an initial VO2max workout target of 7-12 minutes at or above (achieve 95% of VO2max power) to 15-17 minutes at the same target. You can build on this progressively by adding more time at VO2max power each interval workout (or at least most of them). You can progress intensity also, but focus more on progressing time at VO2max.
Interval Intensity Targeting
There are numerous ways to test and determine power at VO2max. The most precise is in a lab, but by using power meters (and some modeling magic), power at VO2max can be modeled fairly accurately. TrainingPeaks’ WKO4 uses the power-duration model developed by Dr. Andy Coggan to supply both modeled VO2max and power at VO2max. This gives us an excellent starting point for targeting individualized VO2max intervals. A general target can be determined simply by testing Functional Threshold Power (FTP) and using a target range of 105-120% of FTP for intervals.
VO2max Interval Length
Since VO2max can typically be sustained for 5-8 minutes, I recommend intervals that range from 2-5 minutes for criterium, road, cyclocross, and mountain bike and 4-8 minutes for time trial and triathlon events. This is not an absolute, just some general guidance. It will generally take about one minute for your body to achieve VO2max, meaning that if it’s done at the correct power, a 4-minute interval will generate approximately 3 minutes of time at VO2max. Based on the overload principle mentioned above, it is possible to start out attempting to achieve 7-12 minutes of time at or above 95% of VO2max and progress to 15-16 minutes total. For example, begin with something like 5 x 3 minutes on followed by 3 minutes recovery, which should result in a total time of 15 minutes in that training zone and about 9-10 minutes of time at or above 95% of VO2max (assuming correct intensity).
VO2max Interval Types
I can tell you a secret: many athletes place too much emphasis on finding the perfect approach to building intervals. Once you correctly target the right physiological system, there are lots of way to achieve success in both interval length and format. I focus on two key formats of VO2max intervals.
These are standard, simple, easy to design, and highly effective. Using the methods above, intervals should target a total time in zone of between 12-24 minutes with the goal of achieving 7-15 minutes at or above 95% of VO2max. These intervals typically have a 1:1 interval-to-rest ratio. An example of this type of interval is 4 x 4 minutes with 4 minutes of rest between intervals.
Tabata or Micro Style
Following the same general guidelines for overall targeting, tabata or micro intervals are typically 4 minutes in length and feature a 20-second hard / 10-second recovery intermittent intensity with a 1:1 interval-to-rest ratio (so a total of 4 minutes of intermittent work followed by 4 minutes of active recovery). This protocol has demonstrated increased improvement in neuromuscular power and anaerobic capacity vs. the steady-state version but will result in lesser time at or above 95% of VO2max.
As a coach, I use both of these formats, taking into consideration periodization, athlete demands, event demands, and athlete preference. Remember, there are lots of ways to achieve success here as long as you target the correct physiological system and plan the appropriate time, intensity, and recovery into the intervals.
This is where the ability to track power and, more specifically, time at VO2max is crucial. Let’s take a look at the chart below of a VO2max workout (the athlete is a UCI MTB pro). This was a solid VO2max workout completed during the first week of an intensive VO2max cycle. It is a 7 x (4 minutes on, 3 minutes active rest) interval set, during which the athlete averaged between 440-450 watts for each interval. Note the time above 95% of VO2max: 16:37. This is a solid workout, hitting and slightly exceeding the desired target of 12-16 minutes at this level. We can further see that during these efforts, the athlete was full on VO2max for almost 5 minutes.
Based on athlete fitness, an intensive 3-5 weeks of VO2max efforts is a solid starting point for scheduling, with 2-3 VO2max workouts planned each week along with some FTP maintenance and aerobic endurance riding.
For a deeper looking into building VO2max / Max Aerobic Power, view this free recorded webinar:
Tim Cusick is the TrainingPeaks WKO4 Product Development Leader, specializing in data analytics and performance metrics for endurance athletes. In addition to his role with TrainingPeaks, Tim is a USAC coach with over 10 years experience working with both road and mountain bike professionals around the world. You can reach Tim for comments at [email protected] [email protected] To learn more about TrainingPeaks and WKO4 visit us at TrainingPeaks.com.