I am not an expert, but cycling keeps a person focused on ONE task. The constant pedalin "drains" the urge for repetitive motion.

Think about it for a second ... in a 10 mile ride a person must pedal anywhere from 10 to 15 THOUSAND times. The urge from doing nonsensical repetitive tasks must be done by the time you finish your commute.

I do not think that a child can accomplish that kind of therapy in the classroom.

... mmm .... thinking of it ... I would get a track racing team staffed completelly by ADD sufferers. Think of the potential, for a fraction of the cost of doctors, medication, and miscelaneous treatment. The most severe cases could be champion sprinters!