The use of a single-case research design to investigate the efficacy of imagery training

Abstract

The examination of the effectiveness of imagery training has frequently produced contradictory results. Single-case research designs have been proposed as potentially useful in overcoming the problem of conflicting results (Wollman, 1986). This paper reports the findings of a multiple-baseline design across individuals examining the impact of an imagery training routine on basketball free-throw performance. Four female basketball players carried out twenty-six trials in which twenty free-throws were scored for accuracy to produce performance scores. Each subject was sequentially administered a basketball specific imagery training routine during the course of the trials. Mental training diaries were used as a manipulation check, and after completion of the experimental period each subject completed a social validation questionnaire. Questionnaire results showed a positive reception of the imagery training routine, and the diaries showed regular training had been completed. Performance scores were plotted for each trial and subjects' graphs were assessed for intervention related change against mean performance change and established Split-Middle analysis criteria (White, 1974). Results suggested only one subject demonstrated a consistent improvement after beginning the imagery training. The results support the usefulness of single-case research designs for examining individual differences to sport psychology interventions. This research approach should prove to be valuable to both the applied and researching sport psychologist.