Abstract: Athletic performance sensing and/or tracking systems include components for measuring or sensing athletic performance data and/or for storing and/or displaying desired information associated with the athletic performance to the user (or others). Such systems can allow users a wide variety of options in creating workouts, selecting and presenting media content during the athletic performance, etc., e.g., to help keep users entertained and motivated. In some instances, user feedback may be used, optionally in combination with objective data relating to a workout, to control features of the workout routine, to control the music or other media content selected and/or presented, and/or to control features of future workout routines and/or the presented media content.

Abstract: Articles of footwear and other devices include modules, e.g., for sensing physical and/or physiological characteristics associated with use of the footwear or other devices. Such devices include: (a) a housing, optionally an asymmetrical housing, for receiving an electronic module; (b) release mechanisms for removably mounting the module in the housing; and/or (c) activation/authentication systems for selectively activating the module. Additionally, methods of making articles of footwear or other structures that include such housings, electronic modules, release systems, activation systems, authentication systems, etc. are described. Performance sensing systems and methods of using the above devices for sensing performance characteristics also are described.

Abstract: Footwear systems include: (a) a holding device having an opening; (b) an article of footwear having a sole with a projection that extends through the opening; and (c) another article of footwear having a sole with a cavity into which the projection extends (thereby sandwiching the holding device between the soles). In other systems, the sole of one article of footwear includes two raised areas that fit through two openings provided in a holding device. The two raised areas fit into recessed areas provided adjacent a raised area of another footwear sole (thereby sandwiching the holding device between the soles). The projection(s) and/or raised area(s) on one sole may be sized and constructed so as to tightly fit (e.g., a friction fit) into corresponding cavity(ies) and/or recessed area(s) provided on the other sole, to thereby detachably hold the soles together and/or detachably engage with the holding device.