I have been experimenting with deep reinforcement learning since watching the DeepMind lecture series on YouTube a while back.

I'm also an obsessive runner, so I figured a good first project to build would be an AI coach for runners. What started out small... quickly turned into something big.

I've been using it myself for a couple of months and been tweaking it continuously. Feeding it new and improved data sets. I think for most normal runners (beginner -> immediate -> advanced) it works pretty well. It might be completely off if you're an elite runner. But I decided it's good enough to release to the world. So I'm launching it as an app for iPhone and Apple Watch (free for now). Would love to get some feedback from other runners.