Increased knee flexion and decreased knee valgus angles and decreased impact ground reaction forces (GRF) are associated with decreased anterior cruciate ligament (ACL) loading during landing. The purpose of this study was to determine the effect of tactile feedback provided by a simple device on knee flexion and valgus angles and impact GRF during landing. Kinematic and kinetic data were collected when 28 participants performed baseline, training, and evaluation jump-landing trials. During the training trials, the device was placed on participants’ shanks so that participants received tactile feedback when they reached a peak knee flexion angle of a minimum of 100°. During the evaluation trials, participants were instructed to maintain the movement patterns as they learned from the training trials. Participants demonstrated significantly (P < .008) increased peak knee flexion angles, knee flexion range of motion during early landing (first 100 ms of landing) and stance time, decreased impact posterior and vertical GRF during early landing and jump height, and similar knee valgus angles during the evaluation trials compared with the baseline trials. Immediately following training with tactile feedback, participants demonstrated landing patterns associated with decreased ACL loading. This device may have advantages in application because it provides low-cost, independent, and real-time feedback.
Boyi Dai, Mitchell L. Stephenson, Samantha M. Ellis, Michael R. Donohue, and Qin Zhu are with the Division of Kinesiology and Health, University of Wyoming, Laramie, WY. Xiaopeng Ning is with the Department of Industrial and Management Systems Engineering, West Virginia University, Morgantown, WV.