Teaching children with ADHD can sometimes be a challenge. Their short attention span and difficulty to organize their tasks make them fail completing them. Their constant fidgeting or running about can be disruptive in class.
Most children are always busy moving around, swiveling in their chair or fiddling with pencils and toys. But they can sit quietly and stay focused as well, like when watching a favorite TV show.
Children with ADHD on the other hand never seem to be able to relax. Their constant wriggling can drive parents crazy. Teachers often try to make them sit still because they believe they will be more concentrated on the task at hand.
Recent studies show that this constant movement is actually helping kids with attention-deficit/hyperactivity-disorder to stay focused. They seem to be able to learn better when they are not forced to settle down.