The importance of the power meter in cyclists' training today is enormous. Professionals have been using it for years, and it's now changing the training of amateur cyclists as well. In this article, we'll review everything you need to know about this gadget.

First things first: what is a potentiometer?

It's a small device that measures the cyclist's pedaling power in watts and displays it on a screen attached to the handlebar (or on a GARMIN, SRM, etc.). It's very lightweight, weighing just 20 grams, and has more than 60 internal sensors that collect all the information we need. It can be mounted on the rear wheel, the crank (usually the left one), the pedals, or the chainring. There are many different models and all kinds of prices, from €500 to €1,700 . The important thing is that it accurately captures all this information so that our training is high-quality.

What is the difference between measuring power and measuring heart rate?

Wattage information is more precise, objective, and instantaneous , allowing us to increase and decrease the intensity of our effort or maintain it as we see fit. Pulse information lags slightly behind the intensity of our effort, and after a period of high-intensity training, it will take time for our heart rate to return to normal. Furthermore, it is very difficult to maintain the desired heart rate level for an extended period. To help you see how different the information we get from one to the other is, consider this: on two different training days, at the same heart rate, we can experience different power levels because we're not always in the same shape or performing as we'd like. Or, looking at it the other way around, we may reach a high power level one day without pushing our heart rate to its limits, or on the contrary, we may push ourselves to the limit without reaching the level we were reaching days before.

Why are potentiometers used so much?

Because they work , they're effective. Thanks to the information they provide, they allow us to plan our workouts in a more impartial and detailed way. Plus, they're not that expensive for what they do. How much did you spend on your last set of wheels, or on that frame you've been saving up for for months? Surely much more than you can spend on a mid-range power meter, which will likely have a much greater impact on your performance. The main advantages we can find in potentiometers are the following: - They're objective ; they measure data, not sensations. They don't focus so much on the speed at which we ride or external circumstances (slopes, weather). They're not influenced by accumulated fatigue, diet, sleep, or health status. - They are quite accurate (although you should always make sure to have it correctly calibrated). - They give us the information instantly . - They make us train better : they teach us how to apply power better on our bike. - They teach us to be patient and to see how, to improve our performance, we have to go step by step, training better. - After the race, they allow us to know how we performed throughout the stage and detect the causes of possible drops in performance. - They help us calculate the calories we have consumed. - We can export the data generated by our power meter to applications such as Strava, Training Peaks, and Garmin Connect , allowing us to plan our training based on objective information.

Okay, so I've broken the bank, bought a power meter, and put it on my bike. Now what do I do?

Before you start, it's advisable to take a " functional threshold power" test , or FTP . It's not like the tests you take at driving school; here you have to sweat, and really sweat, because it involves riding at full speed for 20 minutes (on a trainer or simulator) at a 2% incline. Does that seem like a lot of effort? Don't complain, tests used to last an hour! But doctors Hunter Allen and Andrew Coggan decided to take pity on the poor amateurs who finished the test exhausted and reduced the test time to 20 minutes. By multiplying the result by three and applying a correction factor (because cyclists are always more fatigued and perform less well in the last few minutes), they obtain the data we need: our maximum level , our average value , and the ratio of our power to our weight (measured in watts per kilogram ), among many other data. This watts per kilogram value is one of the most important pieces of information, and it is greatly influenced by the cyclist's weight. Larger cyclists tend to generate more total power, but only because they have to exert more force to move their weight. The heavier the cyclist, the lower their relative power output. That's why smaller cyclists tend to do better on climbs; they are more efficient in terms of the watts per kilogram they are able to move.

The training levels or zones

Once we have completed our functional power threshold test, we will be able to define our 7 training levels, to which we will assign a value in watts. In this way, we can say “if I want to spend 20 minutes in zone 4 (intense effort) I have to run at X watts for that entire time.” Here are the 7 zones we defined thanks to the UPF test we did earlier: Zone 1 (less than 55% FTP ) - Active recovery: easy rolling Zone 2 (56-75% FTP) - Aerobic endurance: run at normal intensity Zone 3 (76-90% of FTP) – Tempo: ride at a good pace, with a certain intensity Zone 4 (91-105% of FTP) – Threshold: intense effort Zone 5 (106-120% of FTP) - Maximum oxygen consumption: great fatigue and oxygen consumption that we can maintain for at most 30-40 min. Zone 6 (greater than 121% of FTP) - Anaerobic capacity: severe effort, usually difficult to maintain for more than 3 minutes Zone 7 (N/A) – Neuromuscular power: maximum level that our body has and that we only use on specific occasions such as jumping, a very short sprint or starting from a standstill. In short, thanks to the power meter , we can know which zone we're in and train for a while in one or the other . If we did it by heart rate, we might only reach the maximum level at the end of a maximum effort. However, in terms of power, we'll be in the zone we choose from the very beginning. Furthermore, we don't always have to push our heart rate to its maximum to generate all the energy. With this method of training, we can learn to distribute our efforts much better.

Interval training using a power meter

Thanks to a power meter, you can optimize your interval training . This topic could be the subject of a whole article, so we'll just cover it briefly. Interval training can be defined as a type of training in which high-intensity efforts alternate with low-intensity efforts (with active recovery) . By working at each effort level according to a set plan, we can achieve the best possible results according to our stated goal. It is the type of training most commonly used by professional teams. For this type of training , using a power meter is a perfect fit because it allows us to better control our efforts, regulate the load more accurately, and rely on more objective data.

So I forget about the heart rate monitor?

No! Not at all! Using watts doesn't mean we have to forget about measuring our heart rate, as it gives us an idea of ​​the internal load exerted by the effort. It helps us understand our body, its reaction, its assimilation of workloads, and assess our physical condition. Ideally, we should use a power meter for objective power data and a heart rate monitor for subjective data on how our body is assimilating to training. So we shouldn't stop monitoring our heart rate . It's an excellent indicator of our fitness level, our health, whether we're eating well, or whether stress is affecting us. As we discussed in the article "Stress Test? Yes or No," it's recommended to have a test at least once a year. In short , the power meter has revolutionized the world of cycling. It's a truly useful power measuring instrument that helps us train better, but that doesn't mean we should stop measuring our heart rate. Although if we're talking "revolution," there's nothing like the Baggicase . Training is great, but what if you went out for a ride and lost your phone or keys and couldn't get back home? Baggicase, just in case!