Systems, devices, apparatuses, components, methods, and techniques for repetitive-motion activity enhancement based upon media content selection are provided. An example media-playback device for enhancement of a repetitive-motion activity includes a media-output device that plays media content items, a plurality of media content selection engines, and a repetitive-activity enhancement mode selection engine. The plurality of media content selection engines includes a cadence-based media content selection engine and an enhancement program engine. The cadence-based media content selection engine is configured to select media content items based on a cadence associated with the repetitive-motion activity. The enhancement program engine is configured to select a media content items according to an enhancement program for the repetitive-motion activity. The repetitive-activity enhancement mode selection engine is configured to select a media content selection engine from the plurality of engines and to cause the media-output device to playback media content items selected by the selected engine.