Summary of Methods: The investigators propose a 2-arm randomized trial that will target increasing MVPA (Get Active) vs. decreasing SED (Sit Less) among community-dwelling, older adults from the Pepper Center Mobility Registry. The intervention will consist of a combination of in-person (Weeks 1-4, 6, 8, 10) and phone-based (Weeks 5, 7, 9, 11) individual counseling and will utilize the BodyMedia® Fit System (wearable armband with technology interface) to provide real-time feedback on daily MVPA or SED, which can be used by the subjects to self-monitor and by the interventionist to improve adherence. Assessments at baseline and 12 weeks will include objectively monitored minutes of MVPA and SED by a blinded armband, physical function (short physical performance battery, 400 meter walk, grip strength, gait speed), and assessment of subjective MVPA, SED, physical function, and psychosocial outcomes by questionnaires.