In principle, tapering should be simple—run less so you're rested for race day. In practice, many athletes find two to three weeks of cutting back on mileage and intensity makes their legs feel heavy and lifeless.
But Spanish coach and physiologist Inigo Mujika, a leading expert on tapering, sees a way around that problem. Mujika suggests athletes start their taper early, scaling back on mileage but not intensity, then three days before the event, "reload" their muscles with an interval workout.
Performing these workouts when your legs are fresher than they've been for months can actually increase your fitness.
(See if you're in race-ready shape with these Four Tests of Your Overall Fitness.)
Indeed, too much rest or slow running lowers the muscle tension in your legs, says Norwegian Olympian and 13:06 5K runner Marius Bakken, which is why they feel flat and sluggish.
Short, fast bursts of running raise muscle tension back up. If you get your taper right, your body will respond by producing more oxygen-carrying red blood cells, lowering stress hormone levels, and storing more fuel in your muscles—enough to shave about three percent off your finishing time, on average.
Here's how to inject some energy into your taper so you shed fatigue and sharpen your edge.
For a marathon, cut mileage to 80 to 90 percent of normal three weeks out; reduce to 60 to 70 percent two weeks out, and 50 percent in the final week.
(Follow this 3-Week Taper Plan for tips on the best way to scale back.)
Maintaining intensity is crucial to avoid losing fitness, so don't slow your easy runs down; for hard workouts, do fewer intervals than you normally would but run them at your usual pace. Stick to one day off: The volume reduction should come from shorter, not fewer, runs.
If you're racing a 5K or 10K, reduce the length of your runs so your total mileage the week before race day is about half of your typical number.
More: How to Plan Your Taper
In the final week, for a Sunday race, take a rest day on Wednesday. Over the next three days, reload by running an interval workout at goal pace, an easy run, and an easy run with strides.
For your interval run, simply modify sessions that you've been doing all along and resist the temptation to blast repeats faster than usual because your legs are fresh.
The easy runs serve to get your legs back into the rhythm and feel of running. Aim to run at your usual pace for half your typical easy-run length, but if your legs feel heavy, add an extra mile and pick up the pace toward the end.