64. ARE CYCLING POWER METERS ACCURATE AND PRECISE?
The biggest cycling technology revolution of the new millennium has been the introduction of portable power meters. Nowadays, this technology is the gold standard for training prescription and monitoring as well as for performance/physiological testing. Given the big business around power meters, different manufacturers are building many different models. As a consequence, we have the following scenario:
different riders can use different power meter models
the same rider can change the power meter model between different seasons as well within the same season.
So, it could be important to understand:
Are power meter accurate? Do they really measure the true power output?
Are power meter precise? Do they read the same watts when pushing the same power outputs on different moments?
A study published by Maier and Colleagues (Swiss Federal Institute of Sports) on International Journal of Sport Medicine in 2017 tried to answer these questions. (1)
WHAT DID THEY DO?
54 different power meters manufactured by different brands were tested: SRM, Powertap, Quark, Power2max, Stages, Verve, Garmin, Polar, Rotor. To assess their trueness and precision, they were tested when cycling on a motorized treadmill setting downhill and with a back pull system. Varying the mass of the back pull system permitted to mathematically calculate the true power that the cyclist had to push to stay on the bike.
To assess trueness: power meters watts were compared with the mathematically derived watts at three different power outputs.
To assess precision: the measurements at the three different power outputs were repeated 4 times to see how near/far they were to each other.
WHAT DID THEY FIND?
Keep reading with a 7-day free trial
Subscribe to Knowledgeiswatt English to keep reading this post and get 7 days of free access to the full post archives.