The purpose of this study was to examine the impact of active learning on student performance in a sophomore-level anatomy and physiology course. Exam grades of students from two consecutive fall semesters were compared. In the first year of the study, students (n=180) used skeletons, plastic muscular manikins, and illustrations to learn the musculoskeletal system while in the second year of the study, students (n=186) also constructed clay models for more active learning. There was no significant difference in average final grade between years, suggesting no difference in overall student ability. For the two laboratory exams over the musculoskeletal system, students who participated in clay modeling performed lower than students who had only skeletons, manikins, and illustrations, and significantly fewer students earned a grade of C (70%) or better on the exams. Surveyed students found active learning useful for visualizing the muscles but few thought clay modeling improved their exam performance.