Why minutes and not kilometres
Your body counts time on your feet and effort, not distance. A 30 km long run takes a 3-hour marathoner about 2h35 at easy pace, and a 5-hour marathoner about 4h18. Written in kilometres, the same session is a solid long run for one and a draining one for the other. Written in minutes, it asks a similar effort of both.
That is the main reason to train by time: the load scales with you. It has practical benefits too. You don’t need a measured route or a GPS watch, and there is no reason to rush an easy run, because finishing faster doesn’t end it sooner.
How Run 42 mixes minutes and kilometres
A Run 42 plan isn’t minutes only. Each kind of run uses the unit that suits its job:
- Long runs, in minutes: from an hour or an hour and a half at the start to a three-hour peak about three weeks before the race, the same for every goal. Three hours is where the gain in fitness stops being worth the recovery.
- Easy runs, in minutes: between 20 and 80 minutes. They are the part of the week that stretches, so each week reaches its planned volume.
- Threshold and VMA sessions, in minutes and metres: efforts like 3×10 minutes at threshold or 8×400 m at VMA pace, about 40 to 60 minutes with the jogs.
- Marathon-pace runs, in kilometres: 8, then 10, then 12 km. These are rehearsals of a piece of the race, so they are set like the race.
The weekly total is still shown in kilometres, because that is how most runners track their volume.
What the minutes mean in kilometres
Easy runs and long runs are run at easy pace, 15 to 27% slower than marathon pace, apart from the marathon-pace blocks in some long runs. Here is the distance each length of run covers at that pace, for five marathon goals:
| Easy run of | 3h00 goal | 3h30 goal | 4h00 goal | 4h30 goal | 5h00 goal |
|---|---|---|---|---|---|
| 45 min | 8–9 km | 7–8 km | 6–7 km | 6–6 km | 5–6 km |
| 1h00 | 11–12 km | 9–10 km | 8–9 km | 7–8 km | 7–7 km |
| 1h30 | 17–18 km | 14–16 km | 12–14 km | 11–12 km | 10–11 km |
| 2h00 | 22–24 km | 19–21 km | 17–18 km | 15–16 km | 13–15 km |
| 2h30 | 28–31 km | 24–26 km | 21–23 km | 18–20 km | 17–18 km |
| 3h00 | 33–37 km | 28–31 km | 25–28 km | 22–24 km | 20–22 km |
The three-hour long run covers well over 30 km for a fast runner and closer to 20 km for a slower one. Both are the right long run for that runner.
Should you run for time or distance?
- Time suits easy running and beginners. It keeps the effort honest, and it makes a first marathon plan less daunting: “90 minutes easy” is a session anyone can follow.
- Distance suits race-specific work. Marathon-pace runs and race rehearsals are about a known stretch at a known pace.
- Distance is easier to compare. Weekly kilometres show your progress at a glance, which is why the weekly total stays in kilometres.
How to follow a time-based plan
- Run the pace, not a distance. If a run says 90 minutes easy, run 90 minutes at easy pace, wherever that takes you.
- On hills and in heat, keep the time. You will cover fewer kilometres for the same effort, and that is fine.
- Don’t chase the weekly kilometres. The total is a guide. A week a few kilometres short at the right effort is a good week.
More on the most important time-based run in the long run, and on each pace in training pace zones.
