The marathon taper: what to do in the last three weeks

A marathon taper is the planned reduction in training over the last two to three weeks before the race. You run less, keep a little pace work and arrive at the start line rested rather than tired. The hard training is already done by then; the taper is when your body finishes adapting to it. The running plan generator builds a three-week taper into every marathon plan, and this guide explains what it does and why.

What a taper is

Tapering is used across endurance and strength sports: reduce the training load before an important event so fatigue falls faster than fitness. For shorter races a week or less is usually enough. For the marathon most coaches use two to three weeks, because the peak weeks of marathon training are long and leave deep fatigue that takes time to clear. The taper usually begins after the last and longest long run, often around 30 to 32 km (18 to 20 miles).

Why tapering works

Training is a cycle of stress and recovery. Big weeks break you down a little; the fitness gains appear as you recover. During the peak phase you rarely recover fully, so you never quite see how fit you are. Cutting the load for a few weeks lets muscles repair, restores stores of muscle glycogen, and lets hormones and energy levels settle, while aerobic fitness, built over months, barely changes in that time. The result is usually fresher legs and a better race than if you had trained hard right up to the day.

How much to cut

The general pattern in a well-designed taper is:

• Reduce volume, often substantially by the final week, in steps rather than all at once.
• Keep some intensity: short sections at marathon pace or a little faster remind your legs of race rhythm. Dropping all faster running often leaves people feeling sluggish.
• Keep roughly the same number of runs, just shorter, so your routine stays familiar.

Exact percentages vary between coaches and runners. Experienced runners with a high mileage may cut more; newer marathoners on lower mileage need less of a reduction.

A three-week example

In the generator's marathon plans the long run peaks at about 32 km (20 miles). The taper then runs:

• Three weeks out — long run about 75 percent of the peak, around 24 km (15 miles), with shorter easy runs.
• Two weeks out — long run about 60 percent of the peak, around 19 km (12 miles).
• Race week — a couple of short easy runs, an easy 15 to 20 minute shakeout with a few strides a day or two before, then the race.

Intermediate plans keep one quality session in the first two taper weeks. The plan also lets you show distances in kilometres or miles and tick off each run. It is a general plan, not coaching; repeat or shorten anything that does not suit you.

Carb-loading and race week

For events lasting longer than about 90 minutes, muscle glycogen runs low and many runners slow sharply, the experience known as hitting the wall, often around 30 km (20 miles) into a marathon. Carb-loading tops up those stores. A commonly cited approach is to eat about 10 to 12 grams of carbohydrate per kilogram of body weight per day for the 36 to 48 hours before the race, mostly from familiar starchy foods such as rice, pasta, bread and potatoes. That is a lot of food for most people, so cut back on fibre and fat to make room, and practise during long-run weekends. During the race itself, take carbohydrate regularly in the form you trained with.

Race week is also about sleep. Nerves often spoil the night before, so banking good sleep across the whole week matters more; the sleep debt calculator shows whether you are running short, and Sleep debt explained: how it builds up and how to recover explains how to catch up. Work out your pacing in advance with the pace calculator, which gives the splits for a target finish time.

Common taper mistakes

• Cramming missed training. A hard long run in the last two weeks adds fatigue without time to benefit from it.
• Doing nothing at all. Complete rest can leave legs feeling flat; short easy runs keep you ticking over.
• Panicking about every twinge. New aches and feeling heavy are common as the body recovers. A sharp, specific pain that worsens is different and worth getting checked.
• Trying something new: new shoes, a new breakfast or an unfamiliar gel on race day.
• Overeating on top of carb-loading all week. The extra carbohydrate matters in the last day or two, not for the full fortnight.

If you trained for a half marathon instead, the same logic applies on a shorter scale: How to train for a half marathon: weeks, long runs and pacing covers the one to two-week version.