Anyone use a running power meter?

I didn't used one, but I can build one and is pretty much worthless.

Has an accelerometer which captures your bouncing. Based on this, an algorithm estimates your effort.

Google made a free app which captures data, but there's no algorithm to tell you something; you are on your own:

https://play.google.com/store/apps/details?id=com.google.android.apps.forscience.whistlepunk

So the power is based on the bounce of your stride? That seems terrible. No wonder I couldn't find any documentation on how they were coming up with this "power" number.

I have one that's really accurate. It's called a stopwatch.

The data is interesting, but not very useful.

I mean you can see that in certain cases you have an imbalance in your motion, but how to interpret that information is a different story.

Maybe the road was inclined, it was a curve, or you had the phone in hand. Who knows what happened?

Just like doing intervals with the GPS. The GPS can be wrong with 3-8 meters in a 400m lap. That's enough to ruin your calculations.

Power meters are common for competitive cyclists, because their speed is greatly affected by wind, hills, and drafting. Those factors affect runners much less, so speed is adequate. I doubt power meters will ever become as popular with runners.

There are some power estimation algorithms for runners that work based on pace and elevation change. The one I use is the power runner plugin for sporttracks.

https://www.zonefivesoftware.com/sporttracks/plugins/?p=power-runner

One thing I don't like about them is that they don't take into account the different kind of energy expenditure that takes place when running uphill vs downhill. A downhill workout can be just as hard on the body as an uphill one but from what I've seen, these power estimators don't have any way to measure that.

If anyone is wondering why anyone would want to measure power expenditure, it's because this is a nice concise way to represent the difficulty of your running at any given point. A good measure of difficulty makes it possible to score the stress that you're putting on your body. Adapting to stress on your body is what fitness is all about. In the past people have used heart rate to measure that but these power-based TSS (training stress score) methods work pretty well too and don't require anything other than a gps track, and might be more accurate.

Heck no...... I barely use toilet tissue.

Not Stryd wrote:

How do these work? How do they account for wind? Can anyone explain this to me?

Also has it helped you in training at all?

The device measures actual power output so wind is not an issue. With pace, wind becomes an issue. It could, should?, give you a more accurate reading of the actual amount of work you are doing.

Not Stryd wrote:

So the power is based on the bounce of your stride? That seems terrible. No wonder I couldn't find any documentation on how they were coming up with this "power" number.

I'm not saying a power meter is useful for running, but that's a perfectly valid way to calculate power

HardLoper wrote:

Not Stryd wrote:

So the power is based on the bounce of your stride? That seems terrible. No wonder I couldn't find any documentation on how they were coming up with this "power" number.

I'm not saying a power meter is useful for running, but that's a perfectly valid way to calculate power

Really? Could you explain a little more? How is that a good way of measuring power?

canyonrunner() wrote:

There are some power estimation algorithms for runners that work based on pace and elevation change. The one I use is the power runner plugin

If anyone is wondering why anyone would want to measure power expenditure, it's because this is a nice concise way to represent the difficulty of your running at any given point. A good measure of difficulty makes it possible to score the stress that you're putting on your body. Adapting to stress on your body is what fitness is all about. In the past people have used heart rate to measure that but these power-based TSS (training stress score) methods work pretty well too and don't require anything other than a gps track, and might be more accurate.

So if a heart rate monitor works, why even worry about a powermeter? Measuring the power doesn't tell you how hard you are working. Measuring your heart rate does.

NotStryd wrote:

HardLoper wrote:

I'm not saying a power meter is useful for running, but that's a perfectly valid way to calculate power

Really? Could you explain a little more? How is that a good way of measuring power?

An accelerometer can measure acceleration in any direction. Thus it can tell you if your acceleration (and force) is forward or if you're wasting energy hitting the brakes or moving side-to-side, as well as roughly gauge speed and power

HardLoper wrote:

NotStryd wrote:

Really? Could you explain a little more? How is that a good way of measuring power?

An accelerometer can measure acceleration in any direction. Thus it can tell you if your acceleration (and force) is forward or if you're wasting energy hitting the brakes or moving side-to-side, as well as roughly gauge speed and power

Thanks for the explaining but that leads me to another question, my garmin has an accelerometer so shouldn't that (bearing the correct algorithms) be able to measure power without a power meter?

Secondly, accelerometers don't seem that accurate, when I'm on the treadmill it's "meh" for accuracy. Maybe wearing it on my wrist instead of the shorts (like stryd) is a factor?

Don't listen to the BS from the other posters in this thread saying you can make a power meter with just an accelerometer. That is complete bull crap from runners that never passed high school physics and have no idea of what is involved. Basic physics will tell you that what they are saying is impossible to do because having only an accelerometer means you have no idea of steady state or external forces. It's the reason cycling power meters all have strain gauges to measure actual force.

talenter wrote:

So if a heart rate monitor works, why even worry about a powermeter? Measuring the power doesn't tell you how hard you are working. Measuring your heart rate does.

Heart rate is a subjective measure. It varies from person to person, and even within the same person day to day. Power output is objective, kind of like mileage but more descriptive. For example say two people ran 20 miles in one week but one person did it at an average 7/mi pace and covered 10000 ft of elevation on trails while the other person did at 10/mi pace on a flat paved road. Clearly the former person's power output for that week was much higher. A good estimate of power output will take those things into account and is a better metric than just distance.

Heart rate might be a good metric too but it's more of the internal state of the athlete than an objective measure like distance, time, or power output.

Not Stryd wrote:

Thanks for the explaining but that leads me to another question, my garmin has an accelerometer so shouldn't that (bearing the correct algorithms) be able to measure power without a power meter?

Secondly, accelerometers don't seem that accurate, when I'm on the treadmill it's "meh" for accuracy. Maybe wearing it on my wrist instead of the shorts (like stryd) is a factor?

Maybe Garmin didn't had the idea of creating a power meter, or they don't think that a power meter for running is a reliable feature.

I don't remember which company was sued because of the accuracy of their heart rate monitor.

Serious companies don't mess with stuff made up of marketing flames. Small startups have nothing to lose.

But as technology, accelerometers are pretty accurate compared with other type of sensors.

Are much faster than any sensor (information/time) and very sensitive to changes.

But the problem is the human factor. We are not stable when running, compared with a bicycle or a car. Just like you said, it matters where you place it.

Not to mention the terrain variations. Climbing, sand, snow, trail, road, track, different shoes, etc....

OMG, YOU CANNOT MEASURE POWER WITH JUST AN ACCELEROMETER. Physics, people.

Neutral Observer wrote:

OMG, YOU CANNOT MEASURE POWER WITH JUST AN ACCELEROMETER. Physics, people.

You didn't "observed" that I was talking about the accelerometer sensor itself, not about measuring power with it.

I'm surprised runners don't use oximeters. That would seem to be a far more useful tool to measure how hard you're training.