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.

This study investigated the effects of four different types of mental practice (free imagery, directed visual, directed reading, and directed audio) on the performance of 45 beginning and 40 intermediate college bowlers. The groups bowled six games with two sets of five minutes of mental practice prior to the first frame and the sixth frame of each game. Data were analyzed by a two-way analysis of variance with repeated measures. No significant differences existed between treatment groups at either the beginning or intermediate levels. Conclusions were that no one technique of mental practice was more effective than another in increasing bowling performance.