I'll take the bait. Great job on the app - seems like it really works. Also answers most questions about how this would be feasible

* How to track workouts where arms don't move? Add a second sensor, or create artificial arm movement.

- Want to track Leg Press? Strap phone to your leg. Or keep hands on your leg to move along.

* How to distinguish between similar workouts/add custom workouts? Custom classification per user means a smaller pool of workouts to distinguish.

- It takes just 3 seconds to train any new exercise