Mental preparation is an important component in athletic performance. Mental preparation often involves imagery of the actual execution of the physical act. Imagery may be either "external" or "internal." External imagery occurs when people view themselves performing an act from the perspective of an external observer. Internal imagery requires that the person feel those sensations that are involved while participating in a physical act. The assumption that internal imagery will be more likely to improve athletic performance was tested using intermediate league bowlers for a period of ten weeks.