Marathon Vert Rennes Groupe Interaction: Course, Route Profile & Map

Course & Elevation

The gun goes at nine on the Mail François Mitterrand, and the finish is on the Esplanade Charles de Gaulle a few hundred metres away in the centre of Rennes. In between lie two identical loops of the city: the course comes back within sight of its own start at kilometre 13.8, 16.5 and 19.6 before running the same circuit a second time.

The elevation profile is essentially a line. The whole course sits between 26 and 41 metres above sea level, with just 115 metres of ascent and 112 of descent across 42 kilometres. What passes for undulation are single rises of eight to twelve metres around kilometre 13, 28 and 31 – nothing at all by marathon standards. The organiser puts the profile at 110 metres themselves and, in 2024, called it the fastest-rolling marathon in France by percentage.

It is a hundred percent city tarmac, through the centre of the Breton capital. 2026 is the 15th edition; the course carries an FFA Gold Label measurement and hosts the Brittany championship. The field's numbers speak for the course: ten percent of recent finishers went under three hours and 65 percent under four. And across the whole event, every two kilometres covered plants a tree with the Fondation Yves Rocher – 21 of them for a marathon.

Pacing Strategy

On a course with no gradient, evenness is the only thing that decides it. Nothing here slows you down and nothing gives anything back: every second you run under target pace in the first ten kilometres is repaid one for one after kilometre 32. Fix your target pace beforehand and run the first loop deliberately feeling too slow.

The race turns at the start of the second loop. Because both circuits are identical, from kilometre 21 you know exactly what is coming – an advantage for rationing and a trap for the head. Check pace and fuelling at the same points as on loop one instead of letting the recognition tempt you into a surge.

The real trap is the field. A very fast course attracts a lot of runners chasing a personal best or a first marathon, and the groups run accordingly ambitiously. Pick your group by your target pace rather than by its speed, and expect the last ten kilometres of a flat course to feel mentally longer than they would on a hilly one.

Training plan for Marathon Vert Rennes Groupe Interaction: 12-week build

Expect 2:30 to 4:30. The demand is about as even as running gets: a continuous aerobic effort with no anaerobic spikes, no strength component and nothing technical. That is exactly why Rennes is a personal-best course – and exactly why it forgives no shortfall in pace durability.

Training centres on long runs at marathon pace. Sessions of 28 to 32 kilometres with extended blocks at goal pace matter more here than hill work or short intervals. Run them on flat tarmac, because that is precisely what the course is, and put the race-pace blocks in the second half of the session so you know that pace on tired legs.

The race-deciding phase begins at kilometre 32. With no gradient forcing you to ease, holding pace there is purely a question of aerobic reserve. Two or three sessions in your build-up should therefore end with twenty to thirty minutes at race pace after a long run. If you are racing the Duo or the Relais, invert the logic: those are a fast half marathon and a 7-to-13 kilometre road race respectively, so threshold work moves to the front.

On conditions: mid-October in Brittany is mild to cool and often wet, and the surface is hard throughout. Train in rain and wind so neither is a surprise on the day, test your racing shoes on tarmac over at least 25 kilometres, and rehearse fuelling at exactly the points in the run where you intend to take it.