From this group of studies, the authors investigated the effects of the following on "performance" loosely defined as the test performed pre- and post-taper:
- Amount of decrease in training intensity
- Amount of decrease in volume
- Amount of decrease in frequency
- Pattern of the taper and its duration
The major findings from this meta-analysis support the current prevailing wisdom that the optimal tapering involves a reduction in training volume without any modification to the intensity or frequency of training. Specifically, the optimal tapering seems to be achieved with a 41 to 60 percent reduction in overall volume.
So if you're used to a 10-hour training week with five days of riding and two days of breakthrough workouts, the volume might drop down to only one hour rides, but there should generally still be five of them, and two of them should remain condensed interval/sprint workouts.
Furthering the drop in volume, the drop does not need to be instant in the very first days of the taper, but it can be a relatively quick drop over the first few days.
In addition, the ideal tapering duration seems to last two weeks. This is somewhat longer than the "traditional" one week that many of us may consider for a taper or recovery week in the typical four-week cycle of training, and also highlights that a taper is a specific program and not just an extended recovery phase.
The key to a taper is that it is a highly specialized training phase designed to promote an overall drop in training stress by decreasing the volume while maintaining intensity. By doing so, it is permitting your body sufficient resources to recover and adapt by temporarily sacrificing your aerobic capacity while maintaining your anaerobic capacity.
Within the above general template, the actual duration of taper and the type of intensity work during the taper varies depending on the event. So a taper for a period of crit racing would differ from that for a time trial or hilly road race, and these would also differ from that for a multi-day or week-long stage race.
The devil is in the details, so it's still important to individualize each taper.
Bosquet, L, J. Montpetit, D. Arvisais, and I. Mujika. Effects of tapering on performance: a meta-analysis. Med Sci Sports Exerc 39: 1358-1365.