CycleOps PowerCal heart rate power meter

Attendees to PressCamp last week were all abuzz with the new PowerCal product announcement from CycleOps. Touted as an introductory level power training product, PowerCal uses your heart rate information to calculate your power output on the bike.

The PowerCal is basically a heart rate strap with a tiny computer that uses proprietary algorithms to calculate your power output based on your heart rate during your ride. To calibrate the PowerCal computer, you must first take a 20 minute test at your local bike shop, where measurements are taken of your heart rate and power output from a real power meter. This data is then transferred to the PowerCal heart rate strap computer via an ANT+ USB stick.

The question is, can a strong correlation between heart rate and power output be proven? CycleOps seems to believe there is a strong correlation, at least while riding on a trainer indoors. The company is currently working with CU Boulder to determine the real accuracy, which they claim is around 5-10%.

The correlation problem comes when you hit the outdoors and you have hills, wind, heat, and many more variables to contend with. Supposedly CycleOps has analyzed thousands of ride data to try and establish the common deviations between heart rate and power output in order to work that into the algorithm. I am curious whether the algorithm takes into account days where you have had too much caffeine or are tired and your heart rate is naturally higher?

The PowerCal heart rate strap is ANT+ compatible so can transfer both heart rate and power output data to your ANT+ cycling computer. Your power in watts and kilojoules shows up next to the rest of your ride data for help with meeting your training goals. 

At only $199, the PowerCal is a more affordable way for cyclists to start playing around with power based training. The CycleOps PowerCal will be available in the October/November time frame. 

Do you think heart rate is a good indication of your power output on the bike?

(via VeloNews)

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  1. There is a correlation between HR and power. But changes in heart rate lag changes in power output by many seconds. So if, for example, you’re doing short duration power intervals, this product is likely to be less than useful. I have a Cyclops PowerTap and it goes like this: in a 1 minute power interval I see a peak in power output at the start of the interval. As the lactate levels build power output starts to fade. My heart revs-up to pump more oxygen to the muscles and to try to clear the excess lactate. At the end of the minute, my power has dropped-off considerably but my heart rate is through the roof. I am not sure how the PowerCal product would manage this…would it show peak power at the beginning or end of the minute? For steady state efforts however, I can see that the PowerCal will likely work ok.

  2. Thanks for your comments Peter! I agree that there is probably a strong correlation during steady state efforts- that is why it works so well on an indoor trainer. For the price, it can be a fun way to play around with power training at least, knowing it may not be accurate in all situations such as those you describe. It would be interesting to compare the PowerCal results to your PowerTap data for a ride.

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