stryd on the shoe
I suspect in 2017 we shall see some increasingly more accurate footpods for running pace hit the market. The STRYD footpod power meter also produces stride length/pace.
I’ve been meaning to test the STRYD as a source of running pace for quite some time but never quite got around to it. On my 920XT I *DO* have the STRYD set to be the ‘always on’ source of pace.
I had noticed any improvement of instant pace accuracy. The 920XT has always been notoriously bad for that, I found, STRYD SEEMED to make it better, but I hadn’t really tested it all the way through.
STRYD do say it is more accurate though.
Regardless. STRYD have just released new firmware to further improve the accuracy of the STRYD footpod as the source of running pace. One of the touted benefits is that no calibration is required.
ESSENTIAL READING: STRYD Review and 10% discount code (here).
The upshot of how STRYD works is that this all essentially means that it should be GREAT as a source of speed on treadmills. Handy for those winter indoor runs.
However STRYD’s post, below, also is interesting in that it shows and neatly summarises potential sources of error with treadmills .Well, I thought it was interesting!!
Info from STRYD Follows:
|All foot pods on the market require pace calibration. But, one-point calibration only works at a chosen running speed, run form, etc. From day zero, we’ve aimed to build Stryd to be a calibrationless technology. While Stryd is accurate, with your data, we’re now more accurate than ever. Shown below is a large number of runs (orange dots) with verified distance and Stryd’s new pace algorithm. Now, we need you to test. Let us know if you see anything out of the ordinary so we can continue to make Stryd even better.|
Mysteriously Low Treadmill Pace
Many runners noticed that running on a treadmill feels differently when compared to running outdoors. Understanding this difference, may actually help improve our run training. After testing on multiple runners and treadmills, we think we have the answer now. The root cause is that treadmill speed is never constant. More specifically, when your body is in the air, the motor applies an extra speed recorded by the treadmill, but not applied to you.
|Notice from the figure above, that|
- belt speed (in blue) reduces at each foot strike, and to compensate,
- the treadmill the motor temporarily over speeds the belt (blue line above Avg belt speed) when the runner is in the air.
The extra distance traveled by the belt (shaded in red) does not cause any extra effort or metabolic cost to runners. Our study shows that such free distance accounts for 2% added distance across commercial grade treadmills with good calibration. (Note: some laboratory grade treadmills with specially designed flywheels are more resilient to such effects).
Let’s ALL Be More Accurate!
When performing our study, we found lots of treadmills which had off calibration, meaning the speed reporting is not accurate. ALL treadmills can be calibrated to an accurate speed without a professional’s help. Here’s how you can do it by yourself, and in only a few minutes.
|Measure true belt length (Using a roll of sticky tape and a tape measure) Manually rotate the belt and place three pieces of tape at points evenly distributed across the belt. Measure the distance between the three and add them together.Measure true belt speed (Using a friend with a stopwatch app) Keep one piece of tape on the treadmill belt, and set the speed you wish to calibrate to. Have your friend watch you run, counting tape (belt) revolutions as they measure time. Stop the timer when you reach 100 revolutions.|
True Belt Speed = Revolutions x True Belt Length / Time
Firmware Update Instructions
- Make sure your Stryd mobile app is up-to-date! Check the version number in either Google Play Store (v3.9) or Apple App Store (v2.7). If you are out of date, upgrade to these versions.
- Upgrade your firmware: Go to ‘Settings’ -> ’Software Update’ -> Press the ‘Upgrade’ button to upgrade.
- Lastly, we need to emphasize two final and critical steps in order to allow you to connect via Bluetooth to Stryd again. After the firmware upgrade is completed, please:
- Completely force the Stryd app to quit. To do that, double-click on the Home button to access the new app switcher or multitasking tray and then swipe up on the app that you want to close.
- Turn off and then turn on the Bluetooth. To do that, bring up the Control Center by swiping up from bottom of your iPhone screen, find the bluetooth icon, click on it twice.
Once you are done with the 2 steps above, you are ready to use your Stryd device with the new firmware installed!