The concept that exercise therapy is an important and integral part of rehabilitation following injury seems to be universally accepted. However, there is little information on athletes' perceptions of understanding their instructions as they relate to the rehabilitation program. A questionnaire study, involving athletes attending a number of multidisciplinary sports injury clinics over a 6-month period, was performed to examine their understanding of the rehabilitation program relating to site, frequency, and repetitions of exercises as well as reason for exercise. Although exercise prescription for injury was assumed to be commonplace, over 150 consultations were observed and only 22 athletes were prescribed rehabilitation exercises (a total of 56 exercises). Seventy-eight percent of these athletes misunderstood some aspect of their programs, although they did not perceive a problem with their instructions. Written instructions were used infrequently (14%), but when used they significantly improved the athletes' understanding. Since rehabilitation adherence is a problem, athletes should receive adequate explanation and written instructions to ensure that the program is followed correctly. Factors affecting treatment adherence are also discussed.