Powermeter: what it is, how it works, how to choose it

Let's start with the simplest question, but also the most important one, to dive into the discussion...

Until the beginning of the 1980s, with the advent of "modern" cycling, no suitable method had been found to verify performance on a bicycle during training or competitions; reliance was still on laboratory tests. This forced athletes to be divided between the data of their actual performance on the bike and that of the laboratory ergometer. These laboratory tests were unable to determine how an athlete's performance might change in training or competition; in fact, these tests represented exclusively a snapshot of the athlete's current state at the time of the test in the laboratory itself.

Who invented the bicycle power meter? 

In 1986, the German biomedical engineer Ulrich Schoberer, after many attempts and experiments, succeeded in the feat of measuring an athlete's power for the first time outside a laboratory in training/race conditions.

Since then, the use of the pedal power meter has started in professional cycling, both in training and race pace management. Even in the amateur world, this direction is being taken with the advent of products that are increasingly accessible to everyone.

A power meter on a bicycle is a device that measures the power output of the cyclist.

And how to measure power on a bike? Power meters base their technology on the principle of the strain gauge, a measuring instrument that detects deformations. The mechanical power is measured through the deformation of a body subjected to stress. The constant deformation of these calibrated parts allows the system to measure the torque (in N.m).

The measure of angular velocity depends on the component in which the power meter is integrated. Thus, in the crankset or in the pedals it corresponds to the cadence of pedaling while in the hub it corresponds to the rotation speed of the rear wheel.

3. Hub Power Meter

The hub power meter in the rear wheel is one of the first to be scientifically validated. It is useful when using multiple bikes because it easily moves from one to another. Some teams have used it to assess the potential of cyclists. The downside is that this system ties the wheel to a single profile without the possibility of changing it.

Training with a power meter has become an increasingly common practice among amateurs.
To start a journey with the various power meters, it is essential to undergo a test to evaluate the cyclist's "engine" together with a coach, to have a starting point to work on and to create a training plan.

The test should be conducted using your own power meter (or if you are using the same product as the coach) to avoid measurement errors. Each meter is "calibrated" by the manufacturer according to its own standard, so testing with two different products could yield very different results and compromise training. The power meter provides a large amount of data and to optimize training, it is essential to know how to read this data and, above all, to know which personal references to rely on. 

1- The first thing to do is to calculate the FTP (functional threshold power) and from there the reference training zones. Moreover, the average wattage expressed during a climb or throughout a workout makes little sense if not parameterized with the athlete's weight. Tackling a 20' climb at 300 watts has a different value for an athlete weighing 60 kg compared to one weighing 80 kg.


2 - To get the best performance from your power meter, it's advisable to have some precautions.

• First of all, it is necessary to regularly perform calibration. The best practice would be to calibrate the device at the beginning of each workout or at least once a week, in order to always have maximum accuracy. The calibration process varies from device to device, but usually only takes a few seconds.
• Another very important aspect, as with all electronic “devices,” is to periodically check for the availability of updates, which can improve the functionality of the bike power meter and resolve any bugs. Each power meter usually has its own management app from which it is possible to check and install updates.

3 - Those who approach the power meter for the first time might start by using the average power over 10 seconds. Power is a data point that is practically impossible to manage because it is subject to rapid fluctuations, even by tens of watts. The most appropriate value to display on your cycling computer for training without going crazy is the average power over 3 seconds. In practice, this is the average power value expressed over the last 3 seconds and is much more stable than instant power. While it is true that power is a more precise and objective value, it is important, at least occasionally, to “cross-check” power data with heart rate data.

Today the market offers a wide variety of power meters, but at Ciclimattio you can find the right expertise to choose the meter that suits you! 
Among the power meters integrated into the crankset, SRM Origin PM9 is the flagship product, the best system, the most expensive and the most scientific. These products are the direct descendants of the first prototypes from the 80s, chosen by many professionals to assess their performance.
As for the measurement in pedals, we must mention the Favero Assioma Duo and the Garmin Rally.

Finally, major manufacturers such as Shimano and SRAM are also incorporating bike power meters into the groups they launch on the market.