I've tried to create workouts to use on my indoor bike trainer, such that I have to target specific power levels for a fixed interval.
You can create this in Garmin Connect but when you send the workout to your device you get a message saying that Garmin Connect is unable to set Power Duration or Power Target.
I've seen other posts highlighting the problem and wonder when this is going to be fixed up.
I e-mailed support on this issue - the reply I got was "Do you have your Edge paired with a power device?" - what a totally crap response. Clearly some tech support guy just writing any response just to clear the action.
