MobilWise, a worksite physical activity intervention for employees at high risk for knee osteoarthritis (OA), is being tested in a developmental randomized controlled trial at a collaborating worksite to determine if remotely- coached physical activity counseling can increase and sustain physical activity in this population. Knee osteoarthritis is a major public health problem and a leading cause of disability and work absenteeism/presenteeism in the US workforce. The overarching goal of this program is to develop and disseminate an affordable, efficient, efficacious physical activity intervention to large groups of employees at risk for knee OA. The Mobil Wise intervention is administered by health professionals, who will use data transmitted from an affordable accelerometer-based personal monitor (Fitbit Flex) via customized remote coach interface to 1) allow the remote coach to view and collect physical activity data generated by the personal monitor, and 2) use that data to formulate and provide tailored behavioral support, using motivational interviewing. This project has the potential to have a tremendous impact on improving symptoms and quality of life of persons with chronic knee pain and decreasing the functional limitation, work absenteeism/presenteeism, and soaring healthcare utilization associated with knee OA.