Abstract: Tracking information is provided from one or more mobile communications devices indicating fitness activity recorded on personal fitness devices of multiple users over a predetermined baseline period of time. A mobile communications device of a challenging user communicates a fitness challenge that is to occur over a predetermined challenge period of time to one or more challenged users. Leveled challenged fitness metrics of the challenging user and of the challenged user is computed based on fitness activity of the challenging user and the challenged user that occurs during the challenge period of time and during the baseline period of time. The leveled challenged fitness metrics are communicated to the mobile communication devices upon completion of the challenge period of time to indicate a winner of the challenge.