CONTEXT: Increased frontal-plane knee motion during functional tasks, or medial knee displacement, is a predictor of noncontact anterior cruciate ligament injury and patellofemoral pain. Intervention studies that resulted in a reduced risk of knee injury included some form of feedback to address aberrant lower extremity movement patterns. Research on integrating feedback into single-legged tasks and the ability to train 1 task and test another is limited. OBJECTIVE: To determine if adding real-time visual biofeedback to common lower extremity exercises would improve single-legged landing mechanics in females with medial knee displacement. DESIGN: Cohort study. SETTING: University laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-four recreationally active females with medial knee displacement were randomized to a visual-feedback group (n = 12; age 19.75 +/- 0.87 years, height 165.32 +/- 8.69 cm, mass 62.41 +/- 8.91 kg) or a control group (n = 12; age 19.75 +/- 0.97 years, height 166.98 +/- 6.89 cm, mass 59.98 +/- 6.24 kg). INTERVENTION(S): Individuals in the feedback group viewed a real-time digital model of their body segments generated by Microsoft Kinect. The skeletal model changed color according to the knee-abduction angle of the test limb during the exercise tasks. MAIN OUTCOME MEASURE(S): Participants completed 3 trials of the single-legged drop vertical jump (SL-DVJ) while triplanar kinematics at the trunk, hip, knee, and ankle were collected via 3-dimensional motion capture. The feedback and control groups completed lower extremity exercises with or without real-time visual biofeedback, respectively. After the intervention, participants completed 3 additional trials of the SL-DVJ. RESULTS: At baseline, the feedback group had 3.83 degree more ankle eversion than the control group after initial contact. After the intervention, the feedback group exhibited 13.03 degree more knee flexion during the flight phase of the SL-DVJ and 6.16 degree less knee abduction after initial contact than the control group. The feedback group also demonstrated a 3.02 degree decrease in peak knee-abduction excursion compared with the baseline values (p = 0.008). CONCLUSIONS: Real-time visual biofeedback immediately improved faulty lower extremity kinematics related to knee-injury risk. Individuals with medial knee displacement adjusted their movement patterns after a single training session and reduced their medial knee motion during a dynamic task.

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