More than 200 riders are expected this weekend at the Trials Training Center in Sequatchie, Tenn., for the AMA/NATC National Championship Series. The two-day competition is sanctioned by the American Motorcycle Association and North American Trials Council.

Riders from the United States, Europe, Japan and Latin America will be among those competing Saturday and Sunday, the third and fourth rounds of the eight-round series. Gates open at 7:30 a.m. CDT, and first riders go out at 8:30 a.m.

Trials riding is an off-road sport where riders navigate obstacle courses on their motorcycles. Riders are not judged by time but on how cleanly they can navigate the course. Riders are given points if they crash, touch the ground with a foot or take more than 90 seconds to get through the obstacle. The competitor with the lowest score wins.

The series comes to North America only once a year, and only the best of the best compete, according to organizers.

Spectators will be able to watch the competition at eight stations. Five are an easy walk along a gravel trail, and three are described as a little more difficult.

Directions to the Marion County site are posted at www.trialstrainingcenter.com. For more information, call 423-942-8688.