The Use of an Inertial Motion Analysis System to Evaluate the Kinematics of Landing before and after a Six-Session Training Intervention Focused on Proximal Hip Strengthening, Motor Control, and Lower Extremity Loading Strategies

Background/Purpose: Studies investigating the trends of anterior cruciate ligament (ACL) reconstruction rates have shown that since 2006, females aged 13 - 17 years of age have had the highest injury rates of any age or gender group in the country. This study investigated the lower chain biomechanics of landing before and after a six-session training intervention. This training ses-sion was conducted between the fall and spring season break for a travel soccer club. Study design: Non-randomized controlled follow-up study. Methods: Thirty-six healthy, female soccer players between the ages of ten and fifteen years old participated. Using an inertial tracking system for three-dimensional kinematic (motion) analyses of a drop jump assessment that were conducted before and after a six-session training intervention focused on proximal hip strengthening, motor control, and lower extremity loading strategies. The study took place over a period of eight weeks. Results: When compared to pre-intervention measures for the drop jump, post-intervention measures were significantly improved bilaterally for each of the following variables: knee flexion (p = 0.000), hip flexion (p = 0.000), and hip abduction (p = 0.002. As compared to pre-test jump height, post-test jump heights were significantly lower by an average value of 1.8034 cm (p = 0.005). Conclusions: The results of this study showed that a short duration (six, 90 min, sessions occurring over 8 weeks) training intervention can significantly influence the landing kinematics in adolescent female soccer players during a drop jump assessment. Increased peak values of hip and knee flexion along with decreased hip adduction during landing indicate a more optimal loading technique associated with decreased risk of ACL injury. The inertial motion analysis system was a useful screening tool for identifying high-risk biomechanics that must be addressed to develop successful ACL injury prevention programs.