Using your inclinometer to measure incline

The Kinni app comes with a fully functional inclinometer in the app.

From Wikipedia:

An inclinometer is an instrument used for measuring angle of a slope of an object with respect to gravity’s direction.

This allows you to measure the incline of your treadmill by holding your phone’s flat edge on the treadmill.

How do I measure the incline of my treadmill?

Incline is more complicated than it would seem at first glance! To explain some of the intricacies, we have written a technical guide on how to precisely measure incline here.

The complexity of writing that guide, in fact, lead us here: we wanted to build a simple tool that allows users to easily, and accurately measure their treadmill’s incline.

So, to measure your treadmill’s incline using the Kinni app, just open the inclinometer, and rest your device on its side on the treadmill.

Here is a photo to help explain:

It’s that easy!

How does this work on a smartphone?

The inclinometer in the Kinni app works with your device’s built-in accelerometer, magnetometer & gyroscope sensors.

The sensors can be used to calculate the device’s position and orientation in space relative to the direction of the earth’s gravity, and it’s movement and acceleration in real-time. This means we get pretty accurate readings, and can use them to figure out some really interesting things, like the rotated angle around a specific axis (incline), or even the proximity of metals!

Did you know your smartphone is also a metal detector!?
Anyway, back to incline…

We use the sensor readings and the “orientation” of the device (portrait/landscape) to calculate the rotation around a specific axis in space relative to the direction of gravity.

This then gives us a basic representation of the slope of the surface the device is resting on, and this is what we display in the app!

Why is incline important?

A lot can be said about why training on incline is important!

Increasing incline increases effective effort, which seems pretty obvious. But, what is interesting is that “energy cost” doubles when doing exercise at ~15% incline according to this study (Perrey et. al.) published in the Journal of Sports Science and Medicine.

Another study (Mohammadi et. al.) shows that walking on an incline increases muscle activity in your legs and ankles, but interestingly, this increase in activity only shows above 5% incline in your non-dominant side. Below that, your dominant side takes most of the extra strain.

There is also evidence that shows that running on a treadmill at 1% incline is the most representative of outdoor running according to this study (Jones et. al.).

Exercising with incline is an excellent way to burn more calories at lower speed, and there is this excellent article over on Polar that explains the differences between walking, running, and effort. Highly recommended!

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