We have been getting reports of the Spinning / Cycling workouts not reporting calories burned on Apple Watch.
It seems like this is an issue with watchOS but we are actively investigating.
At this point, we recommend one of the two options to work around this problem.
OPTION 1: Change the caloric formula used for Apple Watch workouts to our MOTIFIT formula under the MORE TAB > APPLE WATCH in the iPhone app.
OPTION 2: Create a new custom user workout by tapping on the ADD NEW at the top of the Start workout screen in the iPhone app. You can all this workout anything other than Cycling or Spinning and it will create a new custom workout.