In the last few days I posted a couple of tweets about the recovery week and got some good questions back. One of them was about how a recovery week should be designed. I'll get to that shortly, but first a few thoughts on the importance of the recovery week.
First, there needs to be some sort of recovery built into your training, assuming you are training at a workload that is stressful enough to produce fatigue. If you never feel tired then you don't need recovery weeks. If you do accumulate fatigue over several weeks of training then a periodic break from the norm will be good for you. How often you do it depends on how great the fatigue is that you experience. There's no known way of accurately determining this, although the Performance Management Chart at TrainingPeaks.com is pretty good I've found. To use that you need a heart rate monitor, power meter, or GPS device. By uploading your workouts every day it will create a graph which indicates what's happening to your fitness ("CTL"), fatigue ("ATL") and form ("TSB") over the course of several weeks. You'll need about 6 weeks of data for the chart to be of help. But once it is up to speed it will help to confirm what you are experiencing.
Most serious athletes need a recovery week after about two to five weeks of hard training. Again, there's no way of precisely predicting what you will need as far as timing. The best way of determining this is trial and error. But you need to be cautious with trying to see how much fatigue you can accumulate before taking a break. I once knew a pro triathlete who I came to coach who decided to skip recovery weeks and press on regardless of how tired he was. He was never the same again. Overtraining took a big bite out of his performance and he never fully recovered from it. Two years later he retired, prematurely, from the sport.
So back to the original question: How should a recovery week be designed? First of all, a recovery "week" should not be taken literally to mean seven days. Some recover very quickly and may find that in four days they are ready to go back at it again. Others need six or more days. Older athletes are more likely to need longer recovery breaks than younger athletes.
I actually answered the above question very briefly on Twitter recently. The bottom line is that I'd suggest doing only short duration workouts at low intensity for two or three days. "Short" is a vague word that depends on who I'm talking with. If you train 30 hours per week then that may be a two-hour session. But if your weekly volume is more like six hours then "short" means something like 20 minutes perhaps. Of course, one of these days could be a day completely off from training. And probably for many athletes it should be. Or at least such an athlete may want to do something besides their normal sport--cross training, in other words.
"Low intensity" is a little easier to define. That's primarily zone 1 heart rate, power, pace or perceived exertion. Go slow and easy. The purpose of these three days is to rest so don't push the effort on hills or in group workouts. In fact, I'd suggest staying on flat terrain and avoiding everyone else for these two to three days.
Triathletes also need to consider how many workouts will be done in these two to three days. The starting point is to do at least one less workout than you normally do in a day. So if you normally do a session in each sport, leave one out on one of the days and vary which two you do on the others. If you usually do two sessions a day, do only one. Regardless, if you are not recovering quickly during these days then do even less. The purpose is recovery from fatigue--not more fitness. Less is better now.
Now some athletes may need more than three days to start feeling fresh again. If so, it's ok to recover for another day or two. Two or three days is not chiseled in stone. The purpose is to get rid of most of the fatigue. It's best to err on the side of too much rest rather than not enough. More is better here.
After these first two or three days, or when you start feeling like the fatigue is going away, I'd suggest doing two or three days of moderate to high-intensity, low-duration sessions. "Short" duration is the same as the above discussion. "High intensity" means at or slightly above race intensity. This could be short intervals, "speed" work, or testing. The latter is highly recommended. I think it's a good idea to check your progress every four to six weeks so this works out pretty well for about the same timing as recovery weeks.
So a recovery week could look like this...
Monday- Day off
Tuesday- Short, low-intensity workout/s
Wednesday- Same as Tuesday.
Thursday- Speed skills training (see my Training Bible book for your sport)
Friday- Field or lab test to measure progress since last test
Realize that this is only one example, there are many, many ways of doing this. I can't possibly tell you exactly what you should do even if you give me lots of data (I get many such requests from readers). Even when I've coached someone for many weeks it's hard to know the answer to this question with any sense of precision. As mentioned, it's largely a matter of trial and error. Just be conservative. Better to do too little training than too much. You're much better off being slightly undertrained but enthusiastic than overtrained and lethargic.