Get access to everything we publish when you sign up for Outside+.
Training for a race is often compared to baking a cake. You mix the ingredients (speed workouts, long runs, recovery runs, strength and flexibility training, etc.), put it in the oven, and wait to see what happens. But there’s another step, often ignored. When you take the cake out of the oven, you have to let it cool before you assemble the layers to produce the final product.
In running, that cooling process is the taper. And it’s often the easiest to mess up, either because we want to sample the cake now, or because we are afraid it will go stale while cooling.
How you avoid this is part art, part science.
The 7 to 10 Rule
The core principle from the science side is that the body takes 7 to 10 days to adapt to any given training stimulus, says Thom Hunt, a former American 10K record-holder who now coaches at Cuyamaca College in San Diego.
That means once you get within 7 to 10 days of your race, you won’t get any more gains, no matter how hard you train. At this point, your goals are resting, recovering, and waiting for the last adaptations to kick in…while still staying sharp.
“I like to go into a race well rested,” says two-time Olympian Kim Conley, “but it’s a delicate balance to not rest too much and feel flat.”
Additional science comes from a 2007 study in Medicine & Science in Sports & Exercise, led by Laurent Bosquet, now of the University of Poitiers, France.
That paper reviewed 182 prior studies of runners, swimmers, cyclists, rowers, and triathletes, and concluded, among other things, that during their tapers, successful athletes reduced their training volume, but held the intensity of their workouts constant.
So don’t slow down. Instead, reduce volume.
Nor should you suddenly start taking extra days off. The most effective tapers, Laurent’s study found, were ones that reduced the volume of each training session, while not changing how often you train. “Decreasing training frequency does not result in a significant improvement of performance,” he wrote.
Conley agrees. “I’ve learned that keeping the number of training sessions in a week [constant] helps,” she says. “We just reduce the volume.”
How Much to Taper
How much, and for how long, to reduce that volume is more debatable.
Bosquet’s study found that across the five endurance sports his team studied, a two-week taper was optimal. But for runners, he found, it might be more like 8 and 14 days. (He also noted that swimmers can get benefits from relatively long tapers, but it’s impossible to tell whether that works for runners, as well, because it’s hard to get runners to do tapers longer than two weeks.)
As for how deeply to taper, that answer was somewhere between “a lot” and “a very lot”—a figure that, by his team’s findings, might be a staggering 21- to 60-percent reduction in volume per week.
That’s a huge range, but if you take a middle value of 40 percent, that means a 50 mile-per-week runner should cut to 30 miles a week, average, for the final two weeks out (not counting the race itself). At the lower end of the range, 21% per week, it means the same runner should cut to 40 miles per week. A 60% reduction would bring you down to 20 miles per week.
Not that the ideal taper is an instant cut-down, starting two weeks before the race. Rather, Laurent’s team found, it is “progressive,” meaning that it starts small, then builds.
Twenty-one to 60% is a huge range, but the bottom line is that if you find the right degree of taper for you, you can rest assured that you can taper substantially and not crash and go flat. “The biggest mistake people make in tapering is that they don’t trust it,” Hunt says. “Distance runners have to have discipline, but it’s a different type of discipline to back off.”
That said, you can’t just jog. Your taper needs to keep all parts of your training sharp, even as you rest.
What this means, says 13-time Minnesota high-school championship-winning coach Scott Christensen of Stillwater, Minnesota, is that every 3 days or so, you need to do something to keep the aerobic system sharp, while every 4 days or so, you need to do the same for the anaerobic system.
For distance runners, the aerobic bit is easy: a controlled number of reps at 5K effort, or some tempo work, is all you need.
The anaerobic part is more alien, but a few 150s, 200s, or even 400s can do the trick at the end of a (short) aerobic workout, so long as you keep the number of them well within your comfort zone and, in the final days before the race, allow sufficient time between them to truly recover, so you don’t accumulate fatigue that might not clear by race day.
“The key thing is that you give plenty of recovery time,” Hunt says. “You don’t need to push the envelope.”
Consider an Off Day
Conley’s answer to this is something most people have never considered. Six days ahead of a 5K or 10K race, she simply halts. “I take a day off,” she says.
For most runners, this might not sound like a big deal—after all, most don’t run 7 days a week, anyway. But for a pro, it’s a significant pause: a chance to (briefly) hit the reset button, regroup, and refocus. “[It] allows my body to absorb all the [preceding] training and fully rest, while allowing enough time before the race to wake up, and not feel flat,” she says.
She picks the date by counting backward from race day, adjusting her training accordingly. “[That] allows me to use a routine that I know works for me, leading into a race,” she says.
She herself tends to cut volume at the lower end of the range in Laurent’s study: in the final three days dropping from the 25 miles she’d normally do in that span, prior to a speed workout, to maybe 19 in the three days prior to the race (about a 25 percent drop).
But that’s what works for her. What works for you might vary, because, sadly, there is no such thing as the perfect, one-size-fits-all taper.
“Everyone is going to react a little differently,” Hunt says.
Mike Caldwell, coach of the ASICS Greenville Track Club-Elite, agrees. “As with most parameters, we believe there are different types of ‘responders,’” he says. “Some athletes respond to a traditional taper, and some don’t.”
Factor in Your Personal Mileage
Also relevant, Caldwell says, is how much (and presumably how often) you are running regularly going into the race. A 20 to 40 mile-per-week runner already taking one, two, or three days a week off, may need a quite different, and possibly smaller, taper than an elite runner doing 80 miles a week and almost never taking a day off.
But if all of that sounds a bit uncertain, don’t be overly concerned about it — even if you’ve set a taper plan, then accidentally deviated from it.
“I really don’t think we’re that fragile,” Hunt says. “Let’s say that on a day during the taper week you’re scheduled to go six miles at 7:00 pace. If you ran 6½ at 6:45 you’re not going to blow the whole thing.”
Not to mention that part of the taper “game” is mental. Come race day, you want to be mentally relaxed, focused, and ready to go.
All of which means that the “perfect” taper really is part science, part art, and part just trusting it to work.