Preparing for the 2026 Rennes Green Marathon: fast and committed
The Rennes Green Marathon, at the end of October, is known for two things: a fast course and an environmental commitment where every runner gets a tree planted. Point to point between Cesson-Sévigné and central Rennes, it is prepared like a marathon for a fast time. Here is the plan.
Last updated: 2026-09-19
A point-to-point, slightly downhill route
Start in Cesson-Sévigné, finish on Rennes' Town Hall square: the course loses around fifty metres over the distance, with long rolling stretches along the Vilaine and the Ille-et-Rance canal.
It is a personal-best course, with the classic condition of point-to-point routes: no landmark to compare the two halves, the watch is your only judge.
The autumn preparation
Late October: a 16-week plan from early July, or a 12-week plan from early August. The peak load falls in September, with the Breton climate ideal for long runs.
The AI coach follows every week what you actually ran on Garmin, compares it with the plan and decides: next week as is, lightened, or an assimilation week brought forward if the load climbs too fast.
Pacing and the Breton wind
The westerly wind can pick up on the open stretches along the canal. Instruction: target pace in town, low end of the range into the wind, never catching up. On a downhill course, resist the urge to speed up in the first half.
- July-August: volume and a long run up to 2 h.
- September: 12-to-16 km marathon-pace blocks, 2 h 45 long runs.
- October: taper, fresh legs for the Town Hall square.
Schedule the plan's "Race" session on the watch: first three kilometres at target pace plus 10 seconds, target pace afterwards, and the last two kilometres in the centre by feel.
Frequently asked questions
When is the 2026 Rennes Green Marathon?
Late October, traditionally on a Sunday. Check the official date before entering it in your plan.
Is the course really fast?
Yes: point to point, slightly downhill, rolling along the Vilaine and the canal. The westerly wind is the only variable.
What does "green marathon" mean?
The organisation plants a tree per registered runner and runs zero-waste aid stations. Bring your reusable cup.
Ready to prepare for your marathon?
Pick your race date and weekly session count: your AI coach builds the plan and pushes it to your Garmin.
Start the marathon plan