The effect of videotape augmented feedback on drop jump landing strategy : implications for anterior cruciate ligament and patellofemoral joint injury prevention

Background: Modification of high-risk movement strategies such as dynamic knee valgus is key to the reduction of anterior cruciate ligament (ACL) and patellofemoral joint (PFJ) injuries. Augmented feedback, which includes video and verbal feedback, could offer a quick, simple and effective alternative to training programs for altering high-risk movement patterns. It is not clear whether feedback can reduce dynamic knee valgus measured using frontal plane projection angle (FPPA).Methods: Vertical ground reaction force (vGRF), two-dimensional FPPA of the knee, contact time and jump height of 20 recreationally active university students were measured during a drop jump task pre- and post- an augmented feedback intervention. A control group of eight recreationally active university students were also studied at baseline and repeat test.Results: There was a significant reduction in vGRF (p = 0.033), FPPA (p < 0.001) and jump height (p < 0.001) and an increase in contact time (p < 0.001) post feedback in the intervention group. No changes were evident in the control group.Conclusion: Augmented feedback leads to significant decreases in vGRF, FPPA and contact time which may help to reduce ACL and PFJ injury risk. However, these changes may result in decreased performance.Clinical relevance: Augmented feedback reduces dynamic knee valgus, as measured via FPPA, and forces experienced during the drop jump task and therefore could be used as a tool for helping decrease ACL and PFJ injury risk prior to, or as part of, the implementation of injury prevention training programs