They call it "mechanical doping," but the name simply doesn't do it justice. Cycling is not a sport celebrated for honesty amongst even its top riders, but following several very high-profile doping cases in recent years, it seems as though the cheats have been trying a different route: hiding motors in their seat posts that help push them to superhuman feats of endurance.

The technique has been known since at least 2010; commercial versions of the motors can put out 200 steady watts of power, nearly doubling a typical pro-cyclist's output. An onboard motor can help riders go faster, and can keep their pedalling cadence—the number of revolutions through the crank per minute—up while energy dips in endurance stages.

With the biggest cycling event in the world, the Tour de France, set to begin on July 2, mechanical doping is a serious concern—one that has moved France's sports minister Thierry Braillard to tell the French press: "This problem is worse than doping; this is the future of cycling that's at stake."

Until now, mechanical doping has been very hard to unmask. The Tour de France has developed a detection method in partnership with the CEA, the French atomic energy commission. They will use thermal imaging cameras which can detect mechanical anomalies in bikes, with checks made during the race from the roadside. Other more devious tricks will be used, but they are understandably not releasing more details about those to the public.

The authorities hope this system will be able to detect a subtler, more recent development in mechanical doping: neodymium batteries hidden in the rear wheel, generating induction force with a coil somewhere under the seat, and controlled using Bluetooth. This can net the cyclist a few more watts of power that can be fed into a hidden motor.

Christian Prudhomme, the man in charge of the Tour, said: “Protecting the Tour de France is the most important thing. We now have a real deterrent. The cycling world must form a united front to fight against cheating rather than setting off in a dispersed manner.”