Why do you use NP for your training?

Cycling Tips

Normalized power (NP) is one of the most used but also most confusing terms in cycling. Probably you have heard a lot of wrong assumptions about this term. In this article the definition is discussed and how the value is used to analyze your training.

What’s NP? And what isn’t?

Normalized power is actually an algorithm that displays the physiological load of an interval training. This value was introduced by TrainingsPeaks and is used to express the difference in load for the body of a steady state power and a ride with a lot of variation in power. As an example we take someone with an average of 200 watts at steady state pace for two hours and someone else with also an average of 200 watts but with 50 watts the first hour and 350 watts the second hour. Both rides have the same average power, but their NP is clearly different. The physiological strain and differences in intensity of both training sessions are not well expressed when you only look at the average power of these rides. In this case normalized power would come in handy. The calculation of NP gives a more accurate indication of the intensity and strain on the body of these trainings. When the average power quickly increases and decreases (e.g. between two intervals), the NP will decrease less rapidly in this case because the variation in power (intervals) will be included in the formula. With this calculation it is possible to get a better indication of how heavy the interval training was. The calculation of normalized power is quite complicated and sometimes not well understood. Often you hear riders say ‘NP filters out the moments when your power was zero’ or ‘NP is the power you need to deliver to ride at a constant speed’. Both assumptions are wrong.

NP formula

To calculate the NP you have to do the following: calculate a 30 second moving average of the power data, increase this value to the fourth power, take the average of these values and calculate the root to the fourth power. The result of this is the 30 second moving average power, this is the actual definition of normalized power. Now you can actually forget about the calculation of normalized power. The only important thing to remember is that it is a mathematical approach to express the variation in power. Many training parameters are based on NP instead of average power. The whole perfomance management chart, for example, is based on NP. Also the intensity factor (IF) and training stress score (TSS) are based on NP.
NP is often used to indicate the intensity of a prescribed training. Especially when you do intervals above your FTP, the average power of a workout can be low, but NP and therefore TSS are a lot higher because it is a better representation of the intensity of the workout. NP can best be used for the analysis afterwards, it gives a good insight in how heavy the training or competition was.
Finally, you may have noticed the little ‘r’ behind normalized power. This icon stands for a registered trademark, which means that this term and the way this value is calculated is owned by TrainingsPeaks and the company behind it Peaksware. For this reason Strava and among others the training platform Today’s Plan have developed their own value. Not only the name but also the way of calculating differs slightly from NP. But the idea and the principle are the same. It may be that you encounter a small difference between these values, but that is not a problem. You can interpret these values in exactly the same way.

How to get better?

Getting better is all about timing. There are actually not good or bad workouts. There is only a bad combination or the wrong workout on the wrong time. The path of progression is therefore a training plan with the right training stimulus according to your level, goal and available time. To help you with that we developed an algorithm in the JOIN Cycling application. It provides you with a highly flexible training plan to makes sure you get the most out of your rides. You can download JOIN in the App Store and Play store. Or check this page for more info.