Is there a relationship between landing and changing direction in terms of ‘dynamic valgus’?

Background: Anterior cruciate ligament (ACL) injuries are a major problem amongst female athletes. Screening for ACL injury risk tends to focus on landing tasks, which may be limited in sports where changing direction is the main action involved in non-contact ACL injuries such as soccer. Purpose: The aim of this study was to investigate whether there is a relationship between single leg landing (SLL), cutting (90⁰ cuts) and pivoting (180⁰ turns) in terms of characteristics of ‘dynamic valgus’. Study Design: Controlled laboratory study. Methods: Twenty female soccer players (mean ± SD; age: 21 ± 3.9 years, height: 1.65 ± 0.08 m, and mass: 58.4 ± 6.4 kg) performed a minimum of 6 trials of SLL from a 0.3m drop height, cutting and pivoting all on the right leg. Kinematics and kinetics were calculated from 3-dimensional motion analysis. Results: Strong correlations were found for peak knee abduction angles between tasks (R = 0.63 to 0.86, P<0.01), whereas only moderate correlations between SLL and cutting [R = 0.46, P<0.05], cutting and pivoting [R = 0.56, P<0.05], SLL and pivoting [R = 0.43, P>0.05]) were found between tasks for peak knee abduction moments. Conclusion: The results suggest that female athletes who exhibit poor SLL mechanics do the same during various changing direction tasks. Clinical Relevance: The results support the use of existing screening tests that involve landing tasks to identify at-risk athletes for non-contact ACL injuries