The overall objective of this research is to understand how the design of touchless gestural interfaces incorporated into the common computing environment can optimize productivity and efficiency while not exposing users to ergonomic risks. As a first step in achieving this objective, designers must understand fundamental principles about this new type of interaction, which does not require any input device to be touched physically. Human factors issues, such as motor control strategies in unsupported versus supported space, the role of proprioceptive feedback, physical/virtual workspace mapping, and controller-display gain may have significant effects on the overall usability and physical impact of gestural controls. The specific objective of this research proposal is to determine how on-screen task performance for different supported or unsupported upper-limb gesture scenarios is affected by controller-display gain and how these factors influence user adopted posture, effort, and comfort.