I've been using a training plan with workouts from some of Carmichaels books and am pleased with the results. The workouts are based on a percentage of maximum heart rate. Now I am getting a powermeter, and I'm wondering if there is a standard conversion to begin measuring workouts based on power other than heart rate. Do I just perform the standard field test and re-calculate percentages based on power rather than heartrate? Or is there some other kind of method?