Preparing for a 5K, 10K, half marathon or marathon
What changes in the plan depending on the target distance: block length, key sessions, pacing strategy, and how to taper.
Every distance event shares an aerobic base; what changes is the share of the plan given to speed, threshold and durability. The longer the race, the more the specific work matters: target pace, the long run, and your stomach.
| Distance | Block | Prerequisite | Key session |
|---|---|---|---|
| 5K | 8–10 weeks | Running 30 min continuously | 3–5 min intervals at 3–5K pace |
| 10K | 10–12 weeks | 25–30 km/week | 20–30 min tempo + 1,000 m intervals |
| Half marathon | 12–16 weeks | 35–40 km/week and a 75 min long run | Long run with 20–40 min at target pace |
| Marathon | 16–20 weeks | 45–50 km/week for months | 2–2.5 h long run with blocks at marathon pace |
What each block is made of
- 1
Base phase (4–8 weeks)
Build easy volume, introduce hills and strides. No specific sessions yet: this is where you build the ground on which quality later works.
- 2
Specific phase (4–8 weeks)
Sessions that look like the race: 1,000 m intervals for 5–10K, long tempos for the half, blocks at marathon pace inside the long run.
- 3
Taper (1–3 weeks)
Drop volume, keep intensity, arrive rested. See below.
- 4
Recovery (1–3 weeks)
After the race, as many days of easy jogging or rest as the race distance in kilometres divided by three is a reasonable coaching guide; after a marathon, two easy weeks are not too many.
The taper
The best way to arrive fresh is to drop volume, not intensity
The landmark meta-analysis on tapering (27 studies in endurance athletes) concludes the most effective strategy is a two-week taper reducing volume progressively by 41% to 60%, keeping intensity and session frequency, with an average performance improvement of around 2%. Cutting volume by more than 60% makes the result worse.
- 5K and 10K
- 7–10 days
- Half marathon
- 10–14 days
- Marathon
- 2–3 weeks
Cutting volume and keeping short intervals is enough.
Last long run two weeks out.
Last long run three weeks out; after that, just maintain feel.
Nothing new in race week
No new shoes, no new gels, no heroic last-minute session. In the final 7 days you cannot gain fitness: you can only lose freshness.
Pacing strategy
- Start slower than you feel like. The universal mistake is going through the first kilometre 10–15 s under target pace and paying for it over the next ten.
- 5K: almost even pace; the room to push comes in the final kilometre.
- 10K: first 2 km slightly above target, then settle.
- Half: even pace; the elevation makes the changes, not you.
- Marathon: a conservative first half. If you can speed up at km 30, you got the first part right.
To turn a recent result into equivalent training and race paces, VDOT tables remain the most widely used practical reference (VDOT calculator).
Takeaways
- Choose the distance based on the volume you already sustain, not the other way round.
- Base first, specific after; specific means it looks like the race.
- Taper: −40 to −60% of volume over 1–3 weeks, keeping intensity.
- Starting conservatively is the best risk-to-reward strategy at any distance.
- Post-race recovery is part of the plan, especially after a marathon.
Sources for this chapter
- [1]Bosquet L, Montpetit J, Arvisais D, Mujika I (2007). Effects of tapering on performance: a meta-analysis. Medicine & Science in Sports & Exercise. meta-analysis
- [2]Daniels J (VDOT O2) (2026). Calculadora VDOT: ritmos de entrenamiento equivalentes por marca. VDOT O2. resource