If you've ever sat in the last two weeks before a marathon, you know how surreal the taper feels. Suddenly you're running half the miles you've been running all cycle, sleeping a little more, eating slightly differently, and somewhere around day five you become absolutely convinced that you've lost everything you built. That feeling, in my experience, is the hardest part of the taper. It's also where most people end up sabotaging theirs by adding in "just one more workout" or sneaking in a long run that doesn't belong.
What a taper is actually doing
The reason taper works, at least mechanically, is that the fatigue accumulating across your training cycle takes different amounts of time to clear. Glycogen stores come back in a few days. Muscle damage from your big long runs takes a bit longer to repair. Neuromuscular fatigue and the small overuse-injury risks that compound across high-volume weeks need the most time. What the taper is really doing is letting all of that catch up so you arrive at the start line as un-fatigued as possible. The freshness you feel on race morning isn't new fitness; it's a clearer view of the fitness you already built.
The structure that mostly works
For a marathon, two to three weeks of taper is what works decently well for most people. Three weeks if you're coming off heavy mileage (say 60+ miles per week peak) and have the patience for it. Two weeks if you peaked lower or just can't stand the extra week of feeling stir-crazy.
The volume drop is the big lever, and the magnitude matters more than the specific schedule. A reasonable shape across two weeks looks like: peak week, then about 75% of peak, then 50% of peak for race week. Three weeks works similarly, but adds a 90%-of-peak week before the 75% week. The numbers don't have to be exact; the trend just needs to be obvious week over week.
Intensity, on the other hand, you mostly want to keep. Cutting volume but holding 80–90% of your normal pace work (shortened tempos, race-pace bursts, a few strides) is the move. Your body adapts to the intensities it's been seeing, and dropping them entirely for two weeks tells those adaptations to start backing off. A few short fast efforts a week prevent that without adding meaningful fatigue. In Wave, the taper is built into the plan automatically once you set a race date, but the same logic applies whether the plan comes from an app, a coach, or pen and paper.
The mistakes that show up
The most common taper mistake I've seen is the impulse to "lock in" fitness by adding workouts in the last week. It doesn't really work that way. Anything that takes more than 36 hours to recover from in race week is a net negative on race day, no matter how good it felt in the moment.
A close second is novel workouts. Race week is not the time to try a different kind of long run, a new fueling protocol, or a brand-new pair of shoes. Whatever shows up as a surprise on race day is going to be a bigger surprise than it would have been five weeks ago. Race the gear, fuel, and pacing you've trained with.
Third, and probably the most underrated, is sleep regression. Travel, nerves, last-minute logistics. All of it tends to compress sleep in the last few nights. The taper's value is partly that it gives you sleep capital you can spend on race day. Spend more than a couple of nights of that capital in the lead-up and most of the upside is gone.
Race-week specifics
Inside race week itself, the schedule gets a little more specific. A common shape that works: medium-easy run on Monday, short tempo or race-pace work on Tuesday or Wednesday, easy day Thursday, very short shakeout with a few strides on Friday, off or a 15–20 minute jog Saturday, race on Sunday. The intent is to keep your legs feeling "on" without putting any new stress into the system.
The shakeout, when used right, is mostly a nervous-system priming exercise. Fifteen minutes of light running, a few 30-second pickups at race pace, done. The runners I see hurt themselves on the shakeout are the ones who go 4 miles and add "just a couple of fast ones at the end." Don't be that person.
When you don't need a full taper
Not every race needs the full two-to-three-week treatment. A 5K or 10K can usually be done off about a week's worth of taper; three days of reduced volume is often enough. Half-marathons sit somewhere between, but rarely need more than ten days.
The signal to watch is your relationship to fatigue across the last block. If you've been running fresh and your training paces have been holding steady, your taper window can be shorter. If you've been grinding through the last few weeks of the build and your easy pace at fixed heart rate has been creeping slower, you probably need the longer end of the range. That second signal in particular is worth paying attention to, since it shows up well before the more obvious "I feel beat up" feeling does.
A closing observation
The strange thing about a successful taper is that the better you've trained, the worse the last week tends to feel. You're conditioned to expect daily small wins from training, and they're suddenly not there anymore. You feel sluggish, vaguely heavy, and weirdly off. All of that is normal. If anything, it's a decent sign that the taper is working.
The version of you that shows up to the start line is not going to feel like the version of you that finished the peak weeks. That's the point. Trust the work.