The Contre la montre de Marcenat - Trophée J. P. Loisy is a 23 km road cycling time trial held in Marcenat, Allier, central France. It takes place in October as an afternoon event, with riders departing individually to race against the clock. The format is straightforward: a single lap of the circuit for individual competitors and gentleman teams.
The course begins and ends in Marcenat, crossing public roads through communes such as Saint-Didier-la-Forêt, Loriges, Saint-Pourçain-sur-Sioule, and Paray-sous-Briailles. Licensed cyclists and triathletes from any federation are eligible, and non-licensed participants can compete with a valid medical certificate. Riders must be at least 14 years old with parental consent, allowing for a diverse field including club racers, triathletes, younger participants, and local cyclists testing their abilities on a short, direct course.