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How to Train with a Power Meter – Zones & Training Load

By Jiri Kaloc

Power meters have a variety of applications in cycling. You can use them to guide your efforts during rides, track training load, and measure or test your performance. They can be a big help in hitting your goals and reaching your racing potential. Let’s look at these uses in more detail.

Set your power zones

If you want to use your power meter to guide your training, you first have to define your power zones. The number of power zones varies from 3 to 7 based on which model you use. Let’s take a closer look at a 6-zone model, used by Zwift, based on the zones originally defined by Dr Andy Coggan.

Zone Description Power (% of FTP) Duration
1 Recovery Under 55% Unlimited
2 Endurance 56-75% 3+ hours
3 Tempo 76-90% 20-60 minutes
4 Lactate threshold 91-105% 10-30 mins
5 VO2Max 106-120% 3-8 minutes
6 Anaerobic capacity Above 121% 30-180 seconds

The standard way to define your power zones is via the Functional Threshold Power (FTP) test. If you have a power meter, you simply do a session where you ride as hard as you can for 20 minutes. Then you take your average power for those 20 minutes and multiply it by 0,95 to get your FTP value.

Just to compare, if you’re using heart rate to define your zones, then you can only use 5 zones. The 6th zone is an all-out effort you can only sustain for seconds and your heart rate is not able to react quickly enough to be measurable.

Use zones to target specific training adaptations

Each of these 6 power zones has a different purpose when it comes to training. Your coach or a pre-made training plan can take advantage of this. Here are some examples of lactate threshold sessions, endurance sessions, and recovery sessions that are defined by power zones. When you have a power meter, it’s easy to see if you’re staying in the required power range or not. This makes training a lot more targeted and exact. For example, if you want to improve your endurance, you don’t have to worry about going too hard or too easy, just look at your power meter.

Road cyclist
Training with a power meter has revolutionized the way cyclists train and measure their progress. © Profimedia

The goal of a well-formulated training plan is not just hitting defined power zones during each individual ride but accumulating time-in-zone over weeks and months. This gives you insights into the balance and distribution of intensity in your training. For example, a very popular approach called polarized training asks that you spend 80% of time at easy intensity and 20% at high intensity. Without knowing your zones, it’s nearly impossible to track this.

Track your training load

The best way to improve as a cyclist is to balance training stress with adequate recovery. Power data can help you understand how demanding your training is with high accuracy. For example, TrainingPeaks helps you understand the power meter data with a metric called Training Stress Balance (TSB). It compares the amount of training you have done over the last 7 days with the amount you have done over the last 42 days to estimate the degree of accumulated fatigue or readiness to perform.

A positive TSB score means that you trained less over the last week than you have averaged over the last 6 weeks. This suggests you should be well rested and ready to push harder next week. A negative TSB means you’ve trained more and you are starting to over-reach. If you use Strava, then the Fitness/Freshness formula is similar to TSB. It should help you find the right balance between training hard and recovery.

Test your performance

Your power meter can also serve as an objective way to test your performance. You can regularly repeat the FTP test to see how it’s progressing and also to keep your power zones up to date. But you can also test your performance in each zone by measuring your maximum power output for 5 seconds, 1 minute, 5 minutes, and so on. This will reveal your weaknesses and strengths and help you identify what you should be working on the most.

Next up in How to Train with a Power Meter series