Inclusion Criteria:  Female previously diagnosed with breast cancer (clinical stages 1 - 3) Minimum of 3 months post-active treatment completion Maximum of 21 months post-active treatment completion Physically able to complete baseline fitness assessments (e.g., 6-minute walk test, hand grip test, 1 RM leg press) Ambulatory without assistance  Exclusion Criteria:  Active treatment planned within the next 6 months. Known metastatic disease. Currently meeting physical activity guidelines (score of >23 on Godin-Shephard Leisure-Time Physical Activity Questionnaire). Known allergy to Fitbit device or otherwise unable to wear Fitbit device.