A question posed by one of my athletes

I had a question from one of my athletes today.

The question is: What re the benefits of using a power meter and which one is the best? How will it help my training? How will it help you train me?

I would like to answer this question a little differently than some of the other articles out there. Cycleops has a great article’s on their page. I would like to answer it as a coach and an athlete that uses power.

First off I want to dispel a common thought. Power meters are not just for racers. Virtually everyone and anyone can and will make improvements when they use a power meter for their training. If you are just a century cyclist or a beginner triathlete a power meter is by and far one of the best investments you can make.

The reason Why a power meter is so great is for a few different reasons. A power meter directly measures the amount of work you are doing right now and for the whole ride. Also they can accurately and quantitatively measure your ride and give lots of numbers that are important both on and off the bike. These numbers are kilojoules burned (think calories), wattage in average and at the moment, usually heart rate, and many bike metrics as well. The real benefit is when the post ride analysis is done. Post ride I can calculate time in each zone, kilojoules for different sections of the ride, look at average power over intervals and over a period of a week to a year.

In comparison to a heart rate monitor a powertap is an instantaneous and accurate tool. Heart rate lags about 60-120 seconds after an effort is made or stopped. Therefore it is not a true accurate representation of when the work is done. The accuracy really comes into play when analyzing work done on the bike. Because Kilojoules are directly related to calories burned, I can make accurate choices about caloric intake each and everyday when using a powertap. For instance, my friend borrowed my powertap just a few days ago and rode on the trainer. He also wore his standard heart rate monitor as well. When the ride had concluded my power tap showed he had burned 753 kilojoules (about 702 calories) His heart rate monitor on the other hand showed he had burned 1027. This is a very big discrepancy.

Heart rate is also influenced by many factors while off the bike. These factors are hydration, sleep, stress, nutrition, and any medications. One day you can be riding 20mph at 150 bpm or the next you could be at 20mph at 156 bpm. Which one is correct? In some cases it can be a difference in a training zone. Heart rate can artificially inflated or depressed depending on many of the factors listed above. Either way it can be giving false information. However training with heart rate is better than not training with heart rate.

As a coach there are a few basic things I really like to look at. These are the total work load on an athlete. This is good for knowing how far I can push someone before their bodies will start to fight back. Comparison of average heart rate versus average power. This can be a huge indicator of fitness for the day. If the heart rate is abnormally high or low given a power output, I know to investigate further. Last is training stress score and intensity factor. These give me an immediate impression of how hard a ride is. These numbers are much better than just “it was a hard ride today”

Last is testing. Testing with power is a bench mark that can be compared with later. I base most of my testing on a power profile to identify what an athlete needs to work on. Power gives me exact numbers I can compare and contrast against other like athletes, and later down the road after a training load. More on this at a later date .

The power device of choice for me is the cycleops powertap. I personally use this device and have found it to be very easy to use. It is hub that measures torque and can then figure out power based on speed. Its accuracy is +/- about 1.5 %. While this means you won’t have it on race day (if you use different wheels) It is an invaluable tool during day to day training. Often I will race with a powertap to identify my weakness. The model of power tap I use is this one. I like this because it is very affordable and accurate. The upgraded one is nice as it is wireless. But if your on a budget, this is a great tool.

Please email me with any questions regarding power meters or training with power.

Ride Hard

Coach Jordan


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