Training for a marathon: the 16-week plan, week by week

In short Sixteen weeks, four runs a week, mostly easy running, one quality session, a long run that builds gradually to about 30 km, a lighter week every three or four, and a three-week taper.

Before you start: are you ready for a marathon?

A marathon plan isn't a plan for learning to run. Before you start, ideally you've been running regularly for at least six months to a year, three times a week, and can manage an hour to an hour and a quarter of easy running without suffering. Having already run a 10K or a half helps a lot, if only to know your pace.

If that's not the case yet, don't panic: start with a half. The marathon will still be there next year, and your tendons will thank you.

Seeing your doctor before a first build-up is a good idea, especially if you're returning to sport, are over 40 or have a medical history. And check your race rules: depending on the event, a medical certificate, a club licence or an online prevention course may be required.

The four phases of a build-up

A 16-week plan usually splits into four blocks.

1. Base (weeks 1 to 4): build volume gently, mostly easy running, with a little speed to stay sharp.
2. Development (weeks 5 to 8): the long run gets longer, threshold sessions arrive.
3. Specific (weeks 9 to 13): working on marathon pace, for longer and longer. The heart of the build-up.
4. Taper (weeks 14 to 16): cutting volume to arrive fresh, without losing rhythm.

Every three or four weeks, a lighter week lets the body absorb the work. That isn't wasted time: it's where you improve.

Finding your paces

Every session is run at a specific pace. To set them, start from a recent 10K or half-marathon time, run flat out. Online calculators and your watch do the conversion; here are the benchmarks to remember.

• Easy run: a pace where you can talk in full sentences. Often 1 to 1.5 minutes per kilometre slower than marathon pace. Most of your kilometres are at this pace.
• Marathon pace: the one you're targeting on race day. It should feel comfortable at the start of a session: you'll be holding it for hours.
• Threshold: a "sustained but manageable" pace, close to your half-marathon or one-hour race pace. You can still say a few words, not a sentence.
• Short intervals: fast, over short repeats, with recovery.

The classic trap: running easy runs too fast. Slow runs are the foundation of everything. A commonly quoted benchmark is that about 80% of your volume should be at low intensity. It's not a law of physics, but it's an excellent safeguard.

A typical week

This plan has four runs a week. An example layout:

• Tuesday: quality session (intervals, threshold or marathon pace);
• Thursday: easy run, with a few strides at the end;
• Saturday: short, easy run;
• Sunday: long run.

On other days, rest, or a gentle low-impact activity (cycling, swimming, walking). Add two short 20-minute strength sessions a week: core, squats, lunges and calf raises. Your calves take the brunt of the marathon (and sometimes carry a tattoo).

The plan, week by week

This example is for a runner who finishes a half in roughly 1:55 to 2:10 and is aiming for a marathon between 4:00 and 4:30. Distances are guidelines: adjust them to your level, and when in doubt shorten rather than lengthen.

Each quality session starts with 15 to 20 minutes of easy warm-up running and ends with a 10-minute cool-down. The Thursday and Saturday easy runs make up the rest of the weekly volume.

The long run, queen of the build-up

It's the session that teaches you to last. It's mostly run slowly, on purpose: it gets your muscles, tendons and engine used to prolonged effort.

A few common-sense rules:

• The longest run in this plan is 30 km. No need to run 42 km in training: injury risk climbs, so does fatigue, and the gain is small. Many coaches cap the long run at around 2.5 to 3 hours, whatever the distance covered.
• Marathon-pace sections go at the end of the long run, when fatigue has set in: the best rehearsal for race day.
• The long run is also your lab: breakfast, gels, drinks, shoes, socks, kit. Everything you'll use in the race should be tested there.

The last month: the taper

Three weeks out, you gradually cut volume, by about a quarter then by half. Intensity stays, as short marathon-pace sections, so your legs remember the rhythm.

It's often the most unsettling period: you feel heavy, or too fresh, and want to add more. Resist. The fitness is there, the taper brings it to the surface. For the final week we've written a whole article: "Race week: the delicate art of doing (almost) nothing before the race".

Costly mistakes

• Increasing volume too fast. A common guideline is not to add more than about 10% from one week to the next.
• Running easy runs too fast and sessions too slow. Each session has its pace: respect it.
• Making up for a missed session by doing two the next day. A missed session is gone: move on to the next.
• Ignoring pain. Discomfort that lasts more than a few days, worsens with effort or makes you limp deserves a break and the opinion of a doctor or physio. Better a week off than a lost season.
• Neglecting sleep and food. Training also happens in bed and at the table: our article on runners' nutrition will help with the latter.

And on race day?

Start at your pace, not other people's. The first half should feel easy, almost frustrating. The marathon really begins at 30 km, and that's where your training pays off.

And if you've listed your race on Leg Up, those 16 weeks can even earn you a little: your calf worked as hard as you did, it deserves a sponsor.

This plan is a general example. It doesn't replace a doctor's advice or a plan built by a coach who knows your history, level and constraints.