(From a 2011 series of articles)
Tapering is part of the payoff for all the hard work that you have done in preparation for race day. It is a period of reduced volume leading up to your event that allows your body to recover from and adapt to the months of hard training. Tapering often leads to improved conditioning as your well-rested body is able to perform at its best.
Tapering can be tricky and there are a couple of ways that even experienced endurance athletes frequently “blow it.” Some athletes do too much training in the final days and weeks before the event hoping to make up for any missed training over the previous months; other athletes err on the side of resting too much. The goal is to arrive at race day rested, but also well-tuned for the challenge of the day.
During the taper you will decrease your total volume while still maintaining the usual intensity of your training. By resting you will rebuild damaged tissues and recover from minor injuries, as well as restore glycogen (carbohydrate) and other nutrients in your body.
Fitness gains through additional training will be very limited in the last 10-14 days before your event, but gains made due to the “rebound” effect can be considerable. Fitness gains made through months of training can be masked by layers of fatigue. By resting in the last few weeks and “sharpening” with short, relatively intense efforts at or slightly faster than race pace, gains in speed can be considerable
More experienced athletes may use a longer taper with more emphasis on tempo and race pace efforts in the final weeks, whereas less experienced athletes may find that a shorter taper is most effective. It is always better to err on the side of being slightly undertrained than over-trained, feeling like you should do one more long day (you will … on race day!) rather than actually doing it and arriving on race day tired. Don’t forget what the primary goal of your training is: To arrive on race day fit, happy and motivated to take on the challenge!
Keep up the great work!