Detraining
Tapering training volume without enough training stimulus (a mix of volume and intensity) within the taper will result in detraining or a loss of fitness. A study in Sports Medicine found that without the appropriate training stimulus, lactate threshold lowers and capillary density is reduced.
Without taper holding training constant at a low to medium level, fitness increases cease and a performance plateau is reached. Holding training constant at relatively high levels risks overtraining and injury. Ever-increasing training loads, even at relatively small increases, will eventually result in overtraining or injury when the athlete reaches a breaking point.
Those that end up ill or injured usually lose significant amounts of valuable event preparation time due to recovery and rebuilding of fitness.
More: How to Tell When You're Over-Reaching or Over-Training
What Is the Optimal Taper?
Can't train too much, can't train too little; then what is the taper that is just right? I believe the optimal taper depends on race distances, the goal event or events, the volume and intensity of training preceding taper and individual response to tapering, and at least one study in Sports Medicine confirms my beliefs.
Practical Application and Rules of Thumb
I've coached a wide range of runners, cyclists and triathletes. Goal event distances and finish times vary significantly from one hour to 17 hours in a single day. Some athletes race multiday events. Athlete level varies from beginner to professional. Weekly training hours vary from no more than five hours per week to around 30 hours.
With all these athlete samples available to me, the answer for the best triathlon taper is?it depends. It depends on the items listed in "what is the optimal taper" and this is one reason why I give an athlete profile in all of my ready-to-use training plans online or in books. A basic personal profile is a good place to begin.
All that said, I can give you some general rules of thumb from the large number of successful athletes I've coached:
1) If you are tapering as part of a rest/recovery period—not for a specific race performance—during a training block, cut training volume by approximately 40 to 70 percent of the biggest week of training preceding the recovery week. Maintain some intensity in that week from equal to no more than 20 percent of the overall training volume as a starting point. Most of the time, it is best to include small amounts of intensity in training at least every other day and in each sport at least once per seven days. These time segments can be as small as 10 seconds and usually no longer than 20 minutes in a single session.
2) Some triathletes need a rest/recovery period of seven days in normal training. Others do best on five. Still others feel best after 10 days of reduced volume. Life demands have as much, or more, to do with optimal recovery periods as training load.
