Marathon running

A marathon is 42.195 kilometres, or 26 miles and 385 yards. The oddness of the number is a historical artefact rather than a design decision, and the practical consequence is the one every first-timer discovers: the last 2.195km is a meaningful proportion of the race and is where it is usually decided.

What separates it from other running is not that it is longer — it is that the failure mode changes. A 10k is limited by how fast you can run; a marathon is limited by how long you can keep running at all, and the thing that stops people is almost never their legs giving out at a pace they could sustain. It is going out too fast, running out of fuel, or a problem with kit or stomach that would be trivial over an hour and is not over four.

That is why the useful preparation is unglamorous. The long run is where the adaptation happens, the easy runs are what make the long run possible, and race-day organisation prevents more failures than any session does. The marathon is an event where doing the boring things properly beats doing the exciting things well.

The distance

42.195km / 26.2 miles

What actually stops people

Pacing, fuel and admin — rarely fitness

The prerequisite nobody states

A running base, not a starting pointAlmost every plan assumes you already run comfortably for 30 minutes.

Typical first-timer finish

Four to five and a half hoursAnd the spread is enormous. This is a range, not a target.

Almost every marathon plan assumes a starting point it does not state: that you already run three or four times a week and can cover about 10km without it being an event. Plans described as "beginner" usually mean beginner *at the marathon*, not beginner at running. Starting one from a lower base is the single commonest reason a training block collapses in week five, and it collapses through injury or through simply not being able to complete the sessions.

The order that works is: build a running habit, then build a base, then train for a marathon. Compressing that is what people do when the entry is already bought and the date is fixed — which is an argument for entering a marathon that is further away than you would like.

A sequence that does not start with an entry fee:

1. 1

   Step 1: Run regularly for a few months first

   Three times a week, comfortably, without it being a negotiation. This is the base every plan assumes and none provides.

   You will know it worked when: Running is a habit rather than a project.

2. 2

   Step 2: Race something shorter

   A parkrun, a 10k, a half marathon. You learn pacing, race-morning logistics and what your stomach does under pressure, at a distance where getting it wrong costs an hour rather than a season.

   You will know it worked when: The first marathon is not also your first race.

3. 3

   Step 3: Choose the event before the plan

   Date, terrain, likely weather, cut-off time, and how you will get there. A flat local race in spring is a materially easier first marathon than a hilly destination one in August, and nothing in a training plan compensates for that choice.

   You will know it worked when: You are training for a specific day rather than a distance.

4. 4

   Step 4: Work backwards from the date

   Count the weeks and be honest about which of them contain a holiday, a work crisis or a wedding. A plan that assumes sixteen uninterrupted weeks meets nobody’s actual calendar, and the ability to miss a week without abandoning the block is worth more than any session in it.

   You will know it worked when: A plan that survives contact with your life.

5. 5

   Step 5: Decide what a good day and a bad day look like

   Before training starts, not at 30km. Most first marathons are run to a time that was invented during the taper, and the runners who enjoy them are the ones who decided in advance that finishing was the result.

   You will know it worked when: A bad day is a result rather than a failure.

Marathon plans differ enormously in their details and agree almost completely on their structure. Understanding the structure is more useful than following any particular plan, because it lets you tell which parts of yours are load-bearing and which are that author’s preference.

The components, and what each is for:

• The long run — The session the whole block is built around. It develops the ability to keep going, and it is where you practise fuelling, kit and pacing. Most plans build it gradually with occasional easier weeks, and most cap it below race distance — which surprises people and is the near-universal position.
• Easy running — The majority of the mileage, run slower than feels productive. It is what allows the hard sessions to be hard and the long run to be long. Running the easy runs too fast is the most common training error in the sport and it is invisible until the block falls apart.
• A quality session — Intervals, tempo or threshold work, usually once or twice a week. What it is called varies by author; what it does is raise the pace you can hold for a long time.
• Rest and easy weeks — Adaptation happens between sessions rather than during them. Plans that schedule a lighter week every third or fourth week are not being generous — they are the mechanism.
• The taper — A deliberate reduction in volume over the last two to three weeks. It reliably feels wrong: runners feel sluggish, gain a little weight, and become convinced they have lost fitness. That is what the taper feels like when it is working.
• Race-pace practice — Some running at intended marathon pace, so that the pace is familiar rather than theoretical. This is the part most often skipped and most often regretted.

What the plans genuinely disagree about is worth naming, because a beginner reading two of them concludes that one must be wrong. Weekly mileage: some approaches build a large volume of easy running, others get results from much less with more intensity, and both work for different people. Longest run: capping around 32km is common, running the full distance in training is a minority position, and time-on-feet rather than distance is a third approach. Number of runs a week: three to six, with strong advocates at each end. Cross-training: treated as essential by some and as a distraction by others.

None of those disagreements has a settled answer, and a page claiming otherwise is picking a school and not telling you. What they agree on is the structure above, and that agreement is the useful signal.

The marathon punishes optimism more than any other distance. Going one minute per kilometre faster than target for the first ten kilometres does not cost you ten minutes later — it costs considerably more, because it changes how the rest of the race feels and how your fuel is used. The classic marathon failure is not a slow first half; it is a fast one.

The phrase for the consequence is "the wall", and it describes a genuine and specific experience somewhere after 30km: pace collapses, running feels impossible rather than merely hard, and the effort required to continue is out of proportion to the speed produced. It is commonly attributed to running out of stored carbohydrate, and it is also produced or worsened by simply going too fast early. The practical point is that both causes are addressed by the same discipline: start slower than you want to, and take on fuel before you feel you need it.

An even split — running the second half at the same pace as the first — is the standard target and is much harder than it sounds. A negative split, running the second half faster, is what most experienced marathoners aim for and comparatively few achieve. The pace calculator will do the arithmetic; the discipline in the first hour is the part that cannot be calculated.

What is worth deciding in advance:

• Practise fuelling on long runs — Whatever you intend to take, take it in training, repeatedly, at the effort you will be running. Stomachs tolerate very different things and they tolerate less at pace than at rest. Finding out on race day is the classic avoidable disaster.
• Know what the race hands out and where — Aid station positions, what is at each, and whether it is water, sports drink or both. Published on the race website and worth reading, because a plan built around a gel at 25km fails if the station is at 27km.
• Decide how you carry things — Belt, vest, pockets, or relying entirely on the course. Each changes what you can do and each has to be tested on a long run — a belt that is fine for an hour can be unbearable at three.
• Nothing new on race day — Not shoes, socks, shorts, gels, breakfast or coffee. This is the oldest advice in distance running and it is broken constantly, usually because the race pack contained something free.
• Dress for the race, not the start line — You will be cold standing around and warm within two kilometres. Old layers you can discard, or a bin bag, are standard and unglamorous. Most big races collect discarded clothing for charity.
• Anti-chafe everything, before the start — Four hours is long enough for seams to become a genuine injury. This is the single cheapest improvement to a first marathon.

Most marathons are open events with paid entry, and the largest ones are oversubscribed enough to allocate places by ballot. Charity places are the other common route into a full event, and they carry a fundraising commitment that is a genuine obligation rather than a suggestion — worth reading properly before accepting one.

Qualification works differently and applies to a small minority of races. Some events, and the elite or "good for age" categories within larger ones, require a previous marathon time within a published standard for your age and sex. Those standards are set by each event rather than centrally, and they change, so the only reliable source is the specific race for the specific year. What is worth knowing as a beginner is simply that the category exists and is not relevant to a first marathon.

Course accuracy is the thing that makes a marathon time comparable at all. Road courses are measured to a defined standard for record and championship purposes, and a course described as accurately measured under a recognised system means something specific — which is why a watch reading 42.6km at the finish is normal rather than evidence of a long course. Running the shortest legal line through a crowded field is essentially impossible.

A big-city marathon is not primarily a race for the people running it. The overwhelming majority are running against themselves, a substantial proportion are raising money, and the crowd is a genuine part of the event rather than scenery — the difference between running 42km alone and running one with several hundred thousand people shouting is not a small one, and first-timers routinely report it as the thing they were least prepared for.

The etiquette is straightforward and mostly about not ruining somebody else’s day. Start in the pen matching your realistic finish time rather than your hoped-for one. Move to the side before stopping or walking, and look before you do. Take water from the far end of the aid station table where possible, and drop the cup in the bin or the marked zone rather than into somebody’s feet. Thank the volunteers, who are standing in the cold for hours for nothing.

The other cultural fact worth knowing is that finishing times are much less interesting to other runners than beginners fear. The question after a marathon is almost never "what did you get" — it is "how was it", and the answers people remember are about the day rather than the clock.