Building aerobic capacity is essential for most competitive cyclists since anaerobic threshold power (also known as lactate threshold or critical power) is the best single predictor of performance in road cycling races.
What can you do to increase your threshold power without spending more time on your training sessions? The answer is interval training. Probably not a big surprise, but many riders are not aware of the huge benefits there are waiting for them when they start to implement interval training. Not just intervals as you are used to do them.1.Perform a Threshold Power Meter Test
I recommend you do a 20min allout test to get a picture of your current threshold power. In theory it would be even more precise to do a longer test with a duration of 45-60minutes, but I don’t recommend it. If you are the lucky owner of a professional power meter like SRM or PowerTap SL it’s easy to read your average power output in the test. If you do the threshold on an exercise bike it might be little more difficult to calculate your score but it’s still possible.
2.Plan Your Interval Training
Now when you know how many watts you managed to perform in the 20min maximum test, you can plan interval training on these values. The main reason to use a power meter in your cycling training is you get a better and more accurate picture of the physiological parameters you want to improve. An old rule of thumb says that you get good at what you train. Using a power meter makes it easy to train exactly what you want to improve.
In this case we would like to focus on threshold power so we use our test result to plan the interval training. That means that if you hit an average power output of 276W in 20min maximum test, your intervals could look like this:
3 x (8 + 4min) 275 / 140W
That means 8minutes work with a power output around 275W followed by 4minutes with active recovery around 140W. You shall repeat these intervals 3 times which gives a total of 24minutes with 275W and 12minutes with 140W.
3. Ride your wattage controlled intervals
Now you are ready to start your interval training. After a solid incremental warm up you are ready for the interval session. Try to maintain a power output as described, don’t go faster than your training plan tells you to (at least not in the first interval). Interval sessions like these can be ridden 2 to 3 times per week and can be used in various combinations with other intervals.
6 to 8 weeks later you should go back to Step 1 to do another power meter threshold test. Then you can plan new intervals based on your new (and better!) threshold power.