The focus of this chapter lies with the role of mobility in the new fitness boom. In one sense, it would appear that technology has helped make for a frictionless fitness landscape. Fitness technologies tend to be portable, fashionable, and functional in a range of contexts, meaning people need not confine themselves to particular institutional sites to partake in practices like self-tracking. Moreover, the integration of various technological platforms eases the flow of fitness data as well. Mobility in these ways is both material and immaterial in nature. In another sense, however, the second half of the chapter considers how the fitness-technology landscape is perhaps not as frictionless as it first seems, mainly in that the possibility of selling consumer data for commercial gain gives reason for data to flow towards ‘enclosed’ proprietary spaces in the end. Consumers in this regard become not just producers of data, as described in Chapter 3, but producers of value as well. The implications of this pertain largely to the matters of data security and privacy – matters that are explored in this chapter as well.