In my previous post (The S:6 Testing Protocol, Part 1) I talked about the importance of testing to track the progress of your training. Through testing we look to see improvements in power outputs at specific interval durations over 6-12 weeks between testing. I explained how we prefer to test over FOUR different durations:
One longer one at a specific sub-maximal aerobic heart-rate, to identify Aerobic function
Three shorter maximal efforts to identify ones Anaerobic Power.
I also introduced the concept of identifying your Fatigue Rate. This sheds light on where your aerobic fitness, or endurance, is compared to your top-end strength/power. With this data, we can then track improvements in power as well as improvements in fatigue resistance (ie. endurance). Through testing and training we attempt to maximize both ends for peak performance.
The goal with training is two-fold: maximize your power output & resistance to fatigue, ie. endurance. The tricky part is, improvements in one usually results in the decrease in the other; and what gets tracked, gets trained.
Improve your Aerobic Power to improve your fatigue resistance.
The first part of our testing protocol is our Aerobic Threshold (AeT) Test. This includes a 20:00 sub-maximal interval for best average power at your AeT Heart Rate.
What’s your AeT Heart Rate?
Your AeT HR is approximately 80% of your Max Heart Rate. This is the rough point where your energy production, or fuel source, reaches the balance point between fat burning and sugar burning. In general, below this HR we’re burning more fat for fuel, and above this HR we’re burning more carbs for fuel. Training just below our AeT HR we are maximizing our fat-burning aerobic energy system and creating endurance. The faster we can go while maximizing fat for fuel extends how far and how hard we can go in a race. Improved aerobic fitness preserves precious glycogen stores and allows for more power over greater durations. Maximizing aerobic power is a goal for every endurance athlete.
Your Aerobic energy system comprises your longest training durations.
These are your 3+ hour rides at a steady but low intensity. These sessions build your aerobic infrastructure (heart, blood vessels, mitochondria, etc.), and fat-burning capabilities. Your Aerobic Threshold (AeT) energy system, is “next level” fat-burn training while improving the power you can produce while remaining aerobic. Your AeT power would be the max power you can achieve for around 2-2.5 hours. However, our test interval is only 20:00 minutes in duration, so the power number you achieve in the test is not your true AeT Power, because your power would continue to decline if you were to stay at the target HR for another 100 minutes. This 20-minute aerobic power number you see in your test is still valuable as a metric to improve over time as you build your aerobic fitness.
Using our Training Zone Calculator spreadsheet, you will see your 20-minute AeT Power from your test result, as well as your true AeT Power calculated from both your Fatigue Rate and the rough guideline of 85% of FTP.
Identifying your Aerobic Threshold power is part 1 of our 2-part testing protocol. Part-2 is identifying your Anaerobic Power and rate of fatigue as you increase output durations.
Find your Fatigue Rate, here’s how we do it…
After a solid warm-up from the AeT Test interval, we do a 1:00, a 2:00 and a 4:00 test for max power; each with 4-8 minutes recovery between test efforts. With the doubling durations we can calculate the percentage that power drops off between the 1:00 and 2:00 intervals, and the 2:00 and 4:00 intervals. This percentage of decline in power is referred to as your Fatigue Rate. For the moderate to well-trained athlete, this Fatigue Rate remains pretty constant as you extend outwards in doubling durations. Example: 4:00 to 8:00, 8:00 to 16:00, 16:00 to 32:00, and so on.
Using our Training Zone Calculator Spreadsheet, athletes can plug their test results in and the spreadsheet spits out a Fatigue Rate percentage and the resulting training zones specific to their power and rate of fatigue. Not only does the Fatigue Rate help to calculate the training zones, but it sheds light on the “Power vs. Endurance” scale that an athlete is currently experiencing.
A high Fatigue Rate indicates that an athlete slows down at a high rate and could benefit from more endurance training (ie. more “low-end” aerobic training). Conversely a low Fatigue Rate means the athletes endurance is solid, but could use more strength or power training (ie. more “top-end”, as strength training and/or high-intensity intervals).
Over the years we have found that a Fatigue rate between 8-9% to be a good balance point between Power and Endurance.
The end goal then with training is not to simply achieve this balance point, but to continue to increase your “top-end” power: 1, 2, and 4 minute powers, while maintaining a Fatigue Rate of around 8%. This would achieve more power across all durations of output and faster racing!
I was first introduced to this concept of declining output percentages and rates of fatigue as a means to measure fitness many years ago at a coaching conference from a running coach, and soon after from a cycling coach experimenting with power numbers. Since then I have continually been intrigued and have it found it to be very insightful with the athletes I train and have coached over the years.
Our Power Testing protocol does a great job of identifying an athletes top-end power, as well as where their aerobic development is at the time through their Fatigue Rate and AeT Testing numbers. Our goal is always to continually increase the short-power numbers through strength & plyometric training in the gym along with appropriate doses of high intensity training on the bike. As the short duration power numbers rise, we must also address aerobic fitness on the other end to prevent the Fatigue Rate from getting too high. We do this by incorporating longer endurance rides and/or AeT intervals into a an athletes program.
In the end, it’s a continually sliding scale of ‘power vs. endurance’ that must be constantly addressed, and never ignored, in order to maximize performance.
Curious to give our Aerobic and Anaerobic Power Test at try? Schedule your testing at Sessions:6 HERE
Part 3, of our Testing Protocol Series will provide some real world examples from some of our athletes, and what to do with your results.
You can also purchase our 24-Week Off-Season Trainer Series from Training Peaks that includes our testing protocol as well as a complete build through each energy system to improve your top-end power and fatigue resistant endurance. Check it out HERE
Written by Cody Waite, professional endurance athlete, endurance sport coach and founder of Sessions:6 Sport Performance. Looking for help with your endurance sport training? Check out S:6’s Training Plans, Team Programs, and Personal Coaching options created to fit your needs and budget.