The effect of dual-task on jump landing kinematics and kinetics in female athletes with or without dynamic knee valgus.

It has been indicated that dual tasks may multiply the possibility of injuries due to divided attention. This study aimed to investigate the effect of dual-task on kinematics and kinetics of jump landing in female athletes with and without dynamic knee valgus. In this study, 32 recreational athletes between 18 and 30 years old were recruited and divided into with (n = 17) and without (n = 15) dynamic knee valgus groups. The 3-D positions of retroreflective markers were recorded at 200 Hz using a 8-camera Kestrel system (Motion Analysis Corporation, Santa Rosa, CA), while ground reaction forces were synchronously recorded at 1000 Hz using 2 adjacent force plates (FP4060-NC; Bertec Corporation, Columbus, OH). Kinematics and kinetics of jump landing were recorded while counting backward digits as a dual task, and also without counting backward digits as a single task. One-way repeated measures of variance were used to analyse data at the significant level of 95% (α < 0.05). The study found that the dual-task affected the angles and moments of hip, knee, and ankle joints (P < 0.05) in both groups. Additionally, the effect of the dual-task differed significantly between the two groups in the angles hip flexion (P < 0.001), knee abduction (P < 0.001), and ankle internal rotation (P = 0.001), as well as the moments hip flexion (P < 0.001), hip abduction (P = 0.011), knee flexion (P = 0.017), knee internal rotation (P < 0.001), ankle dorsiflexion (P = 0.046), ankle eversion (P < 0.001), and ankle internal rotation (P = 0.046). Athletes with dynamic knee valgus may have been less able to protect themselves during the landing and are more prone to lower extremities injuries. As a result, using kinematics and kinetics in athletes with dynamic knee valgus during landing may help identify potential mechanisms associated with risk factors of lower extremity injuries and ACL injuries as well.