The 10 km
Thirty-five to sixty minutes, close to your limit the whole way.
Everything that decides endurance performance matters here — your ceiling, how much of it you can hold, how efficiently you run 1. At this length, the ceiling matters most.
It is also the distance where a bad first kilometer cannot be fixed. Two hundred meters of enthusiasm costs you the rest of the race.
- What it needs: repeated work at and just above race pace, with enough easy running underneath to do it twice a week.
- How it fails: starting too fast, and arriving with a ceiling you never actually pushed.
- How long: eight to twelve weeks from a reasonable base.
The half marathon
Seventy-five minutes to two and a half hours, at an effort you can just about hold.
That puts it close to the pace you could sustain for about an hour. Long continuous efforts at a controlled, uncomfortable-but-holdable pace do the most good here.
It is also the friendliest distance for a first serious attempt. Long enough to demand real preparation. Short enough that a food mistake does not end your day.
- What it needs: long intervals and continuous blocks at threshold, plus a long run that is genuinely long for the race.
- How it fails: running the first 5 km at 10 km effort, and underestimating how specific 21 km is to 21 km.
- How long: ten to sixteen weeks.
The marathon
Two to six hours at a pace that feels easy for the first hour and steadily less so after.
Your ceiling is not the limit any more. What decides it is whether you can still run efficiently, still absorb food, and still think clearly, deep into the race.
It is the only common road distance where eating is part of the event, and where getting the first 10 km wrong stays invisible until the last 10 km 2.
- What it needs: long runs with real time at race pace, and a food plan rehearsed at race effort.
- How it fails: going out faster than you trained, and reaching 30 km having eaten a fraction of the plan.
- How long: twelve to twenty weeks. More if you are building the base at the same time.
Finishing versus racing
These are two different plans. Confusing them is the most common mistake we see.
| Finishing | Racing a time | |
|---|---|---|
| What decides it | Reaching the start line healthy, having covered enough ground | Time spent at and around race pace |
| Long run | Time on your feet. Effort does not matter | Time on your feet with race-pace blocks inside |
| Hard sessions | One a week is plenty | Two a week, for a defined stretch |
| Biggest risk | Doing too much too soon | Doing the right sessions at the wrong intensity |
One thing that is not a shortcut. Modern racing shoes do improve running economy, measured properly, on trained runners at racing speeds 4. The effect is real. It is not a substitute for the block of training in front of it.
What we don’t know
The tables above describe practice. We would rather say so than dress them up.
No trial has compared plan structures between distances. The long run in particular — how long it needs to be, whether the famous thresholds mean anything, whether race-pace blocks inside it help — has almost no experimental evidence behind it. It is the biggest hole in the field.
What is solid is narrower: how trained runners distribute their intensity 56, what tapering is worth 7, and the nutrition numbers in the fuelling guide. Everything else on this page is informed convention, and we label it as such.
Questions people actually ask
Can I train for a 10 km and a marathon at once?
How many weeks for a first marathon?
Do I need to run 30 km in training?
Is a half a good step towards a marathon?
References
Every figure above rests on one of these studies. Author and year are enough to find the paper.
- Joyner (2008)
- Smyth (2021)
- Kim (2025)
- Hoogkamer (2018)
- Seiler (2010)
- Casado (2022)
- Bosquet (2007)
