Weekly Summary

Week 8 to 14 May


Cambiar idioma

If you have been totally disconnected, I will now summarize what has happened on the web during the last week and the latest updates in the sports technology sector (so that you don't miss anything). There are also small notes of interesting links that I have found on the internet these days. If you find something interesting that you think is worthwhile, let me know by Twitter or Facebook From time to time I also share or retweet information or links of interest, so don't forget to follow me on social networks if you want to know them all. Here are the highlights of this week.

This week's articles

No news this week. The reason? I'm working on evidence to publish within very little.


Product Updates

You don't know if you have to connect your device to update it? You received an automatic update and you don't know what it includes? Well, I'm here to tell you.


Links of interest

The most interesting links I have found this week. Almost all of them are curious news related to sport.

  • Study shows that power meters have inconsistencies - And my answer is that we already knew this... and that the study is very limited. All manufacturers already indicate the accuracy factor of their power meters, which is usually around ±1-2%. They themselves confirm that there may be inconsistencies, and for many reasons. As for the study itself, I have not had access to the full documentFor example, doing the test in a laboratory and comparing the data with a mathematical formula. To begin with, the power meters are prepared to work in a real environment, where there are vibrations, temperature changes, potholes, constant differences in the intensity of pedaling... Eliminating all these factors may not be a problem... or create a conflict. Apart from the fact that we are doing a laboratory test of something that we are interested in knowing how it works in the real world. It's like the consumer approvals of cars, in the end nobody pays attention to it.

    With respect to the standard, a mathematical formula is being used to determine what the valid power would be at a given speed. How do we know that this formula is accurate at all times and throughout the power range?

    But let's go further. You don't use a machine without any percentage of error, but you use a cyclist on a treadmill. What is the possible human factor error? Because I doubt very much that we can consider it from the 0%, since it is impossible for any human being to be able to maintain an exact power of, for example, 250W for 10 minutes and for the entire duration of the pedaling. Not 250.1W or 249.9W. Exactly 250W for the entire pedaling cycle.

    And what about the technical aspects? Because it is striking that power meters that measure one leg and double the power are being mixed in the same study, along with others that measure total power or those that measure power separately. Especially in cases like the Stages, where we return to the human factor. It is impossible for the cyclist to have an exact distribution of the 50% in his pedaling power, as we saw in my test of this power meter.

    More technical aspects, because we also don't know how the data has been collected and in what way. A power meter has a recording rate of 8 hz (that is, it can collect data 8 times per second), while the common ANT+ units do it at 4 hz. What happens with those four measurements every second that are lost? Because in power peaks measuring a tenth before or a tenth after can give two very different values. And of course, create inconsistencies.


    Are you taking into account where in the transmission chain the data is being recorded? Because from the pedal to the hub there are losses due to the transmission, the bending of the frame, the wear of the chain, its lubrication... All the tests have been carried out on the same bike, or is there more than one bike involved? Even if they are of the same make and model, their rigidity does not have to be the same. Is the lubrication of all the components exactly the same throughout the laboratory test, or could differences have been created by wear and tear?

    The study ends with the following words: "In conclusion, current power meters used by elite and recreational cyclists vary considerably in their trueness; precision is generally high but differs between manufacturers. Calibrating and adjusting the trueness of every power meter against a first principle-based reference is advised for accurate measurements."

    Again, it's a lot of trouble (and quite expensive) to come to the conclusion that we already knew, plus the manufacturers already warn. Power data between two meters doesn't have to be exactly the same, starting with measuring it at different points. And calibration of any power meter is key to good records, as detailed in any manual for such a device.

    So, does this study serve any purpose? Well, simply to confirm that a power meter is not a measuring instrument. It is not an engineering tool that is designing a part of a bridge under construction, where a deviation of a 2% can mean a catastrophe.

    Can you rely on a power meter for training and competition? Of course. Can you even use reference data between two different models of meters that you use on two different bikes? I see no objection, as long as you understand how the power meter works and where it is measuring.

  • More news for Stryd - Stryd continues to bring new things to the table. They are keeping up with the pace for a small company and are proving to be very active. Powercenter receives more updates and presents trends, to see how your performance improves or worsens over time. Also metabolic fitness graphs (in my case it confirms that I have been preparing correctly for the 10km of the Olympic triathlon), muscle power (which has been increasing over time) and muscle endurance (which has peaks that correspond to competitions...

    But the best part is that Stryd is not only showing information, but providing data on what it's good for and giving suggestions on how we can improve our performance, something that doesn't always happen with other utilities.

  • Apple acquires Beddit - Beddit, not Reddit. This is a Finnish company that markets a device that is placed on the mattress, transmitting the sleep information to a smartphone. It will be interesting to see what Apple is doing with this technology now; whether they will keep it as it is (as an external accessory) or if they plan to use their technology to add it to the Apple Watch.

And with that... thanks for reading!

Eduardo Mateos

I've been surrounded by electronic devices of all kinds for more than 25 years. Using them, testing them, taking them apart and dissecting them. Long distance triathlete: I swim, run and cycle for a long time. Maybe too much.

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