Extended periods of time sitting in front of a computer give rise to risks of developing musculoskeletal disorders. In the workplace, computer use contributes considerably to employee injury and results in significant costs to the employer in terms of sick leave and injury claims. Due to these risks there has been significant research into the areas of posture classification and subject intervention to improve posture in an office environment. The Kinect has been shown to be a suitable hardware platform for posture classification. This paper presents a system for posture classification and novel subject intervention that leverages each of three distinct forms of persuasive computing and explores the success of each type. Our results show significant improvement in posture results from the most effective of our intervention types.