In this study, we examined the effectiveness of instructional materials designed to control redundancy and split attention in the teaching of complex orthopedic physical therapy skills. Participants included 41 first-year physical therapy students. The modified instruction group received a modified unit of instruction designed to reduce cognitive load, while the control group received a traditionally designed unit of instruction. Four hypotheses were tested relating to achievement on cognitive and psychomotor tests, ratings of cognitive load, and task completion times. The multivariate analysis yielded significant results for three of the four hypotheses (ES = +0.52). As predicted, the participants receiving the modified instructional materials scored significantly higher on the written post-test and psychomotor tasks, while reporting a lower level of cognitive load on both tasks. These results suggest that designers can increase the germane cognitive load by reducing the extraneous cognitive load through good instructional and message design practices.