The immediate effects of expert and dyad external focus feedback on drop landing biomechanics in female athletes: An instrumented field study

Document Type


Publication Date



Background Anterior Cruciate Ligament (ACL) injury prevention interventions have used trained experts to ensure quality feedback. Dyad (peer) feedback may be a more cost-effective method to deliver feedback to athletes. Purpose To determine the immediate effects of dyad versus expert feedback on drop landing kinematics and kinetics in female athletes. Study Design Cohort study Setting College gymnasium Methods Two teams (one female basketball and one female volleyball), from a local college, were team randomized to dyad feedback (volleyball team) or expert feedback (basketball team) (13 expert, 19±0.87years, 1.7±0.09m, 68.04±7.21kg) (10 dyad 19.4±1.07years, 1.73±0.08m, 72.18±11.23kg). Participants completed drop vertical jumps at two different time points (pre-and post-feedback). Knee flexion and abduction displacement were assessed with Inertial Measurement Units (IMUs) and vertical ground reaction force (vGRF) was assessed with a force plate during the landing phase of the drop vertical jump and compared across groups and condition (pre-and post-feedback) with a repeated measures ANCOVA a priori α 0.05). Between groups there was a decrease of vGRF in the expert group (difference 0.45 N*bw-1, p=0.01) at post-feedback relative to dyad. Within the expert group there was a significant difference between pre-and post-feedback (difference 0.72 N*bw-1, p=0.01), while the dyad group did not change pre-to post-feedback (difference 0.18 N*bw-1, p=0.67). Conclusion Movement screening experts giving real-time feedback were successful in improving key injury-risk kinematics and kinetics in female athletes, while dyad feedback only improved kinematics, indicating that expert feedback may be needed to ensure changes in kinematics and kinetics. Level of Evidence 2.