This thesis attempts to problematize and rethink the inter-related construction of the categories of "environment" and "fitness". It argues that environments are materially and discursively constructed through the mutually constitutive mobilization of networks of human and non-human actors by particularly powerful centers of translation, and that these processes increasingly involve the construction of environments configured to the requirements of an ideal of fitness - a fitness defined in terms of risk, flexibility, response-ability, responsibility, mobility, and consumption. In developing this argument particular attention is given to the relations between bodies and technologies as actors constitutive of the networks from which environments are constructed. As a specific illustrative example of this, the efforts of the fitness equipment manufacturer NordicTrack to mobilize and translate diverse networks of actors in the space of the home and then represent these hybrid networks as ontologically purified, meaningful and marketable environments are examined. The ontological and spatial ambiguity of the types of environments constructed by corporations such as NordicTrack is then discussed, this ambiguity being registered in the difficulty of positioning the boundaries between categories such as subject and object, nature and culture, human and machine, real and virtual. Finally, having illustrated that these ambiguous environments are perhaps constituted by communities of human and non-human actors, this thesis then suggests that such a recognition might open up space for critical geographical imaginations that are responsive to the possibility that political, ethical, and moral community and agency are co-constructions of humans and non-humans. / Master of Science