lower extremities and trunk kinematic asymmetry during single-leg landing in preadolescent female soccer players

Background: asymmetry may be associated with non-contact anterior cruciate ligament (acl) injuries among female athletes. the study aimed to assess the lower extremities and trunk asymmetries during single-leg landing in preadolescent female soccer players, providing insight into the underlying neuromechanically factors that may increase injury risk during critical developmental stages. methods: a total of 36 preadolescent female soccer players (10-12 years old) voluntarily participated in the study. the kinematics of the trunk and lower limbs were analyzed using a three-dimensional motion capture system. peak joint angles were obtained at the time interval between initial contact and peak knee flexion during single-leg drop landing. a paired t-test was used to compare kinematic variables between limbs, and symmetry was calculated with a normalized symmetry index.results: landing on the dominant limb significantly exhibited larger peak hip angles in the frontal plane (p=0.00, d =0.94), larger peak trunk lateral flexion (p=0.00, d=-0.46), larger peak trunk flexion angles (p=0.00, d=0.46), and smaller peak knee rotation angles (p=0.01, d=-0.44) than on the contralateral limb. also, the highest asymmetry value based on the normalized symmetry index was observed for peak knee rotation. conclusion: preadolescent female soccer players displayed greater hip and trunk angles in the frontal plane during single-leg drop landing on the dominant side. these increased angles may lead to greater loads at the knee joint and indicate greater risks for acl injuries on that side. coaches should emphasize interventions targeting symmetrical movement patterns and neuromuscular activation, particularly focusing on core stability and hip abductor engagement, to mitigate injury risk in this vulnerable population.