Normalized Power in Cycling: History, Definition, and How to Use NP in Training

Cyclists today are blessed with advanced cycling training metrics that make sense of every ride. One key metric is Normalized Power (NP). If you’ve trained with a power meter, you’ve likely seen NP alongside your average watts. But what exactly is NP, and why is it so important? This article will explore the history and origin of Normalized Power in cycling, explain what NP means vs. average power, and show the practical benefits of using NP for training and racing. You’ll also learn how NP is calculated, which tools provide NP data (TrainingPeaks, WKO, Garmin, Zwift, etc.), and get tips on how to use NP in cycling – from endurance rides to intervals and race pacing – to improve your performance. Let’s dive in.

History and Origin of Normalized Power

Normalized Power as a concept was developed in the early 2000s by exercise physiologist Dr. Andrew Coggan, a pioneer in power-based training. Dr. Coggan is credited as the originator of Normalized Power, and he introduced the term to the public in 2006 with the book Training and Racing with a Power Meter, which he co-authored with Hunter Allen. This was around the time power meters were becoming popular in cycling, and coaches needed better ways to analyze the data.

Coggan’s work led to Normalized Power being incorporated into the CyclingPeaks software (now WKO) and the TrainingPeaks platform, which trademarked "Normalized Power" (hence you often see it written as NP®). Since then, NP has been widely adopted in cycling training and analysis. It’s now a standard metric in the toolkit of cyclists and coaches, alongside other power metrics like Intensity Factor (IF) and Training Stress Score (TSS) that Coggan also developed. In fact, NP is used in the calculation of those metrics – highlighting how central it has become to power-based training.

What is Normalized Power (NP)?

Normalized Power is essentially an adjusted power value that better reflects the true effort and physiological stress of a ride, compared to a simple average power. NP answers the question: “How hard would this ride have been if I’d ridden at a constant power output?” It accounts for the fact that in real cycling, power output is variable – you coast, you surge on hills, you sprint out of corners – which makes the ride’s demands on your body different than a steady effort.

Dr. Coggan describes NP as an estimate of the power you could have maintained for the same physical cost if your power output had been perfectly steady. Because it considers how your body responds to hard efforts and recovery, NP provides a more accurate measure of intensity than raw average watts. It’s a metric that correlates better with how you felt during the ride (and how much it fatigued you) than average power alone.

Normalized Power vs. Average Power

To appreciate NP, it helps to compare it with plain average power. Average power is just the arithmetic mean of all your watts over a ride. It treats a steady 200 watts the same as wildly fluctuating between 0 and 400 watts (as long as the average is 200). But anyone who’s done the latter can tell you it’s far more exhausting than holding 200W steady! This is where NP comes in.

For example, imagine two cyclists each finish a 2-hour ride with an average power of 200 W. Rider A kept a steady 200 W the whole time. Rider B spent the first hour noodling at 50 W and the second hour hammering at 350 W. Both rides average to 200 W, but the stress on Rider B’s body is immensely higher due to that brutal second hour. Normalized Power reveals this difference – Rider B’s NP will be much higher than 200 W, reflecting the greater strain and intensity of that variable ride. Average power alone would have masked how hard Rider B actually worked, whereas NP correctly weights those intense efforts.

In short, average power doesn’t always tell the full story in cycling, especially for rides with a lot of coasting or surging. Normalized Power addresses this by giving more credit to hard efforts. As a result, NP often ends up higher than average power on workouts like interval sessions or hilly races, indicating they were harder than the average wattage suggests. On a perfectly steady ride (like a flat time trial), NP will be very close or equal to average power; but the more variability in effort, the more NP will exceed the average. Coaches sometimes look at the ratio of NP to average (called Variability Index, VI) to gauge how smooth or variable a ride was. A low VI (NP ~ avg) means a steady pacing; a high VI means a lot of surges.

How Normalized Power is Calculated

The Normalized Power calculation involves a bit of math to properly weight the harder efforts. Thankfully, you don’t have to calculate it yourself – your cycling computer or software will do it – but it’s useful to understand the principles. Here are the basic steps to compute NP:

1. 30-Second Averages: First, take your ride’s power data and calculate a rolling 30-second average for every point of the ride.
2. Fourth-Power Scaling: Next, raise each 30-second average power value to the 4th power (i.e., P^4). This mathematical step ensures high power values are emphasized much more than lower ones.
3. Average the Values: Take the mean (average) of all those 4th-power values.
4. Fourth-Root: Finally, take the 4th root of that average. The result is the Normalized Power for that ride or segment.

In formula terms, if P_i are the 30-second smoothed power samples, then:

NP = ((1/n) * Σ (P_i^4))^(1/4)

This formula ensures that periods of high power (which drive up the sum of P^4 significantly) boost the NP, while low power/coasting periods (near zero, whose 4th power is negligible) have little effect.

Benefits of Using Normalized Power in Training and Racing

• More Accurate Intensity Measurement: NP provides a better gauge of how hard a ride really was on your body, avoiding the misleading nature of average power.
• Training Load Tracking: NP is used in calculating Training Stress Score (TSS) and Intensity Factor (IF), both of which help determine how much training load you accumulate.
• Race Pacing and Strategy: By using NP during races, you can monitor intensity and ensure you don’t overdo it early in an event.
• Fitness Tracking: Over time, increases in NP for the same perceived effort indicate improvements in fitness.

Conclusion

Normalized Power is one of the most valuable metrics in modern cycling training. It provides a more accurate reflection of effort and fatigue than average power alone. Understanding NP helps cyclists train smarter, analyze races better, and improve their overall performance. Whether you use Garmin, Zwift, TrainingPeaks, or TrainerRoad, NP is a key number to track for better cycling results.

By incorporating NP into your training analysis, you can ensure your workouts are structured properly, your races are paced effectively, and your fitness improvements are well-monitored. Train smart, ride strong!