The best results seem to follow when the taper is at least one week long, the volume reduction is at least 50 percent compared to the previous week, and the tapering period includes a fair amount of race-pace efforts (instead of being entirely low intensity). For example, in a study from East Carolina University, a group of runners lopped an average of twenty-nine seconds off their 5K race times after completing an eight-day taper in which their training volume was reduced by 70 percent compared to the previous week and a small number of race-pace intervals were run each day.
As a general rule, the higher your peak training volume is, the longer your prerace taper should be. Indeed, one of the reasons that runners before Emil Zátopek did not taper is that they tended to train very lightly compared to today’s standards—so lightly that they didn’t really need to taper. If your last heavy week of training includes 20 to 40 miles of running (or the equivalent in running and cross-training combined), then a one-week taper is sufficient. If your peak training week includes 41 to 80 miles or the equivalent, then a two-week taper is necessary. And if your last hard week includes more than 80 miles of running or the equivalent, then you should taper for three full weeks, as most elite runners do before marathons and half marathons. The training plans presented in Chapters 10 and 11 follow these guidelines.
Note that it’s not the distance of your race—marathon or half marathon—that should determine the length of your taper but the amount of training you do. If you run 41 to 80 miles per week in training, for example, you should do a two-week taper regardless of whether you’re preparing for a marathon or a half marathon. As we’ll see later, most of the nutritional guidelines for the taper period apply to both marathons and half marathons.
The most common mistake that runners make in tapering is doing too little high-intensity training during the final one to three weeks before racing. Research has consistently shown that a taper featuring a fair amount of high-intensity training is more effective than one featuring only easy efforts. While the overall volume of high-intensity running you do during the taper period should be reduced compared to the peak training period, your easy training should be reduced to a much greater degree.
Most of the high-intensity training efforts you do during the taper period should be undertaken at your goal race pace or slightly faster. You want your body and mind to be as fully adapted to this specific intensity level as possible. You may also do a very small amount of near-maximal intensity running for a last-minute boost in power and economy.
Whether you’re training for a full or half marathon, I recommend that you perform your last “hard” workout three days before your race. This workout should feature enough high-intensity work to leave you mildly fatigued. Your final two days of training should consist of nothing more than warm-ups and maybe a few relaxed sprints to keep the nervous system primed.