Trackball sensitivity refers to the amount of trackball movement that the system requires to identify the movement as a navigation event, and to send a navigation event to the software layer. The BlackBerry® device hardware measures physical trackball movement by using units called ticks. When the number of ticks along an axis surpasses the threshold of the system or a BlackBerry device application, a navigation event is sent to the software layer, and the system resets the tick count to zero. Tick counts are also reset to zero after a certain amount of idle time passes.
You can use the Trackball API to set the trackball sensitivity. High trackball sensitivity equates to a smaller tick threshold (a small amount of trackball movement generates a navigation event). Low trackball sensitivity equates to a larger tick threshold (a larger amount of trackball movement is required to generate a navigation event).