Performance Devices

There is a term in sports analysis called TEM, if you don't know what this means then I suggest you read on.

TEM is an acronym for Technical Error of Measurement, every device, either mechanical or computer will have some form of TEM.

A few years ago, when I was an athlete, I used to use a Wattbike at the local gym, there were three of them and the one I always tried to use I'm sure it read a lot higher than the other two bikes. If this bike wasn't available I would go and do a gym session or run on the treadmill as my ego wanted to feel good about pushing higher numbers on the bike.

Looking back this was a ridiculous approach as there was pretty no accuracy to the session I was doing, on the flip side psychologically I felt good about myself, but that's another story.

Accuracy and Validity: The Key Considerations

There are two things we need to look at when selecting devices to measure our performance: accuracy and validity. Accuracy seems a simple concept as one could argue, if I know it reads too high I can just deduct a few beats/watts or whatever. However, if your heart rate monitor was reading 20 beats too low, this potentially has you training in an intensity you may not want to be in.

The reason why validity is important is if you know the accuracy of your monitor is always reading low you can compensate, but what if it reads high one day and low the next. Many wearables and power meters are tested in laboratory conditions, in the real world many external factors, such as temperature, and vibration can have a major impact on the validity of the device.

The Key Message

The key message is all measurements should be taken as an approximation and not the truth, use them as a guide and try to combine different metrics such as rate of perceived exertion, (RPE) speed and time (if running or swimming), heart rate and power (running or bike). But just remember the TEM.