hi DrMom,
Per Medicine Net.com, the definition of isometric is:
Definition of Exercise, isometricExercise, isometric: Exercise involving muscular contractions without movement of the involved parts of the body. Isometric exercise is one method of muscular exercise. In contrast, isotonic exercise occurs when a contracting muscle shortens against a constant load, as when lifting a weight.
Isometric comes from the Greek "iso-", equal + "metron", measure = maintaining the same measure, dimension or length.
So I would agree with you 100% - it is not an isometric contraction when the joystick moves. Isotonic contraction would be more accurate I would think.
Hope this helps.