With about three weeks to go until race day you start the Peak block of training which lasts two weeks. There are three things you must do in the Peak block if you are to come into good form for the race. The first is to reduce the duration of your workouts. For the next two weeks, each hard workout should be shorter than the previous one. The second is to do a race-like workout every third day. These are hard workouts that simulate some portion of your A-priority race. And the third is to allow two days to recover between the race-like sessions. This is the key to success now.
These recovery workouts should not be taken lightly. If you make these too hard the quality of your next race-like workout is compromised. This is the most common mistake I see athletes make when peaking. These recovery sessions should be primarily zone 1 effort, heart rate, power or pace. There may be a few cumulative minutes of zone 2, but these should be brief incursions lasting no longer than a couple of minutes at a time. Strictly avoid zones 3 and higher. You should feel guilty about going so slow. People will pass you. That’s ok. Your purpose is only recovery; you are not trying to boost race fitness on these days.
If you make the hard workouts progressively shorter while taking two days to recover between them the quality of the hard workouts will be high. This will bring you to a peak of race-readiness.
The Peak block is explained in much greater detail in my books – The Triathlete’s Training Bible, The Cyclist’s Training Bible and The Mountain Biker’s Training Bible.