A course is as described, but a workout is totally different and in no way followed in the same way as a course. Basically it is a set of steps which you create to achieve a training objective ie pedal for so long at a certain cadence/speed/heart rate, rest, repeat step 1, rest, repeat step 1 again but slightly altered etc etc, its best performed on an indoor trainer, or better still on flat roads, unless you have created a hill climbing workout. I use workouts quite a lot especially during the winter months and can be as simple or as complex as you like.
Check the manual out as it describes it better:-
http://static.garmincdn.com/pumac/Edge_800_OM_EN.pdf
Check the manual out as it describes it better:-
http://static.garmincdn.com/pumac/Edge_800_OM_EN.pdf