What one missed long run costs
Endurance is built by a series of long runs over many weeks, not by any one of them. Lose one, and most of what the series has built is still there. Early in a block, when the long runs are still well short of their peak, a single miss costs very little.
What costs more is the rescue. Squeezing 25 km into a Wednesday, or running it the day after a hard session, puts a big load on legs that are already tired from the rest of the week. That kind of spike is how a missed session turns into a missed fortnight.
Your options, in order
- Skip it. Most of the time this is the right call. The week keeps its shape and next week's long run goes ahead as planned.
- Move it within the week, if there is a day that is not right after a hard session and not the day before another one. A day or two later is fine.
- Carry it into next week, onto a day that was a rest day, and make next week's easy runs shorter by the same distance so the week does not grow.
What doesn't work: spreading its kilometres over the easy days, splitting it into two medium runs, or running it the day after a Tempo or an interval session.
When it matters more
The last two or three long runs before the taper are the longest of the block and the closest thing to a rehearsal. Missing one of those is worth moving if the week allows it. Still, don't run it on tired legs, and don't push it into the taper: the taper exists to shed fatigue, not to catch up.
Missing two or three in a row is a different problem. If illness or travel took the days, see the guide on missed days. If it keeps happening because the long run doesn't fit your week, move it to a day that does, for good.
What Roen does
General training information, not medical advice. For pain that does not settle, or any symptom that worries you, see a doctor or a physiotherapist.