Osteoarthritis (OA) is a complex disease for which there is no non-surgical cure. In 2005, approximately 9 million American adults were diagnosed with knee OA. A host of treatment options for knee OA are currently available; however, an efficacious non-surgical therapy for preventing disease progression remains to be identified. Exercise has been a mainstay of OA therapy for years, but its effects beyond pain palliation and improvements in daily function remain to be elucidated. Specifically, it is unknown if exercise can affect the altered biomechanical loading characteristic of knee OA. The overall goal of this research was to examine the effects of a biomechanically based, focused hip muscle exercise regimen aimed at decreasing load at the knee joint, a known risk factor for disease progression. Load was assessed by measuring the external knee adduction moment, an established surrogate marker of medial knee joint loading, through gait analysis. The specific aims of this thesis were to examine knee joint loading before and after the exercise intervention in subjects with medial compartment knee OA. Aim 1 examined the changes in knee joint loading after completion of 4 weeks of supervised exercise targeted at the hip musculature. Aim 2 examined changes in activity level, knee joint loading and cumulative knee load after completion of 4 additional weeks of independent home exercise. These parameters were also compared to those observed in a population of healthy, older adult controls.