We put five leading wearables to the indoor running test

Most of us would much prefer to run outdoors in the open air than grind out stationary miles on a gym treadmill. But unless you live in a climate where it’s pleasant all year round, the chances are that at some point you’ll end up hamstering on the dreadmill. And when you do, you want a running watch or fitness tracker that can take care of business.

The good news is that most watches and running wearables are equipped to track your time on the treadmill swapping the GPS for motion sensors like accelerometers to to track the movement of your arms while you run, and by crunching the data it gathers with an algorithm, they’re are able to estimate the distance you’ve moved.
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Read full post here:
https://www.wareable.com/running/best-running-watch-for-treadmill-training-7054