How much does tapering actually matter?

Tapering is one of those running rituals that gets far more attention than it probably deserves. For weeks you build up your mileage, nail your long runs, fine-tune your pacing — and then suddenly you’re supposed to stop. The “perfect taper” is meant to be the secret weapon that unlocks your best marathon performance.

But how much difference does it really make?

A big data study published in Frontiers in Sports and Active Living looked at exactly that. Researchers analysed the tapering patterns of thousands of runners using Strava data, and the results are not quite as dramatic as you might think.

What the science says

The researchers looked at the training data of over 158,000 marathoners to see how their tapering affected performance. They compared how runners reduced their training volume in the weeks before race day, and they controlled for sex and fastest 10k pace — which, unsurprisingly, turned out to be the biggest predictor of marathon time.

Here’s what they found:

• Runners who did strict, longer tapers — steadily cutting down training for two to three weeks — performed best.

• The difference between a relaxed two-week taper and a strict three-week taper was roughly two minutes faster.

• The best result, a strict three-week taper, was about four minutes quicker than no taper at all.

• A four-week taper was actually less effective, suggesting you can taper too much.

So, tapering helps, but we’re not talking about life-changing gains here.

What that means in real life

Four minutes sounds like a lot on paper, but that’s the extreme end of the data. For most runners, the difference between a good and a great taper is closer to a minute or two at best.

To put it in context, drafting (tucking in behind another runner to save energy) can save a similar amount of time. We’ve got a video on that too, if you fancy the science behind it.

The point is, tapering matters, but it’s not a miracle fix.

And like all big data studies, there are limits. Strava data can be messy, think GPS errors, incomplete uploads, or people pacing a friend instead of racing flat out. The findings are useful, but not gospel.

The Kaizen takeaway

Tapering works, but you don’t need to obsess over it. The science suggests that even a simple one-week taper gives you most of the benefit.

At Kaizen, we usually recommend cutting your training volume by around 30 to 40 per cent in the final week, keeping a few faster efforts but with plenty of rest between runs or sessions e.g. intervals. You’ll arrive fresh, sharp and ready, without the stress of over-analysing every run.

FAQs: How to Taper Before a Marathon

1. What is tapering, exactly?

Tapering means reducing your training load in the final weeks before a race so your body can recover, adapt and perform at its best. You still run, just with less volume and more rest.

2. How long should a taper last?

Two to three weeks works well for most runners. The research suggests three weeks is best, but the difference between that and a good one-week taper is small.

3. How much should I reduce my mileage?

Cut your peak training volume by about 30 to 50 per cent. Keep a bit of intensity short tempo or marathon pace efforts but skip the long runs or unnecessary extra miles.

4. What if I only have time for a short taper?

No problem. A one-week taper still gives most of the benefit. Focus on recovery, nutrition and a few short runs to stay confident.

5. Should I stop strength training during taper?

Not necessarily. Reduce the volume and avoid anything that leaves you sore, but light maintenance work can keep you balanced.

6. What mistakes should I avoid?

Doing too much: a big last long run can leave you flat.

Doing too little: total rest for two weeks can make you sluggish.

Overthinking: small details won’t make or break your race.

7. Can tapering ever hurt performance?

Only if you overdo it. Four weeks or more of reduced running can make you lose rhythm and fitness. One to three weeks is the sweet spot.

8. Should I change how I eat or sleep during taper?

Yes. Prioritise sleep, hydration and balanced meals. You’ll burn fewer calories, so reduce portions slightly but keep carb intake steady, especially in the final few days.

The bottom line

Tapering helps, but it’s not the game-changer many runners think it is. A consistent training block, solid recovery and good pacing will always matter more. Keep your taper simple, trust the process and show up fresh rather than frazzled.

🎥 Watch: Josh breaks down how much tapering really matters before your marathon →