As we discussed in the launch party, the reason we write the Tuesday and/or Thursday double workouts for high-volume plans is to allow you to make the best decision on how to fit this into your day. Here are the guidelines for making your decision:
GOOD: If you're just too busy, get in one of the workouts.
BETTER: If you're sort of busy, do one in the morning and one in the evening.
BEST: Do the workouts back to back if you have the time.
By writing them in your training plan as doubles, you have the ability to make your own call and arrange however you see fit.
So should you do the double workout as written? During the first eight weeks of BaseCamp, the double workouts are written so that you can simply repeat the workout twice, but remember: if you're feeling some fatigue, do a second workout as an hour of aerobic endurance instead of the written workout. We've been teaching you how to target, so you should know what your aerobic endurance range is by now. As the athlete, you know how you feel; trust your gut and make the call.