9 Wearable activity trackers; sports training apparatus featuring electronic sensors and recorded and downloadable software to analyze sport performance; computer monitors for providing training instructions during an exercise; portable media players; recorded and downloadable software for portable media players that provide training instructions during an exercise; sports glasses; frames for sports glasses; cases for sports glasses; lenses for sports glasses; cases for contact lenses; sunglasses; protective glasses; protective helmets; sports helmets; visors for helmets