Boys demonstrate greater knee frontal moments than girls during the impact phase of cutting maneuvers, despite age-related increases in girls

Purpose Anterior cruciate ligament (ACL) injury rate is low among children, but increases during adolescence, especially in girls. Increases in the knee valgus moment within 70 ms of contact with the ground (KFM 0-70 ) may explain the sex-specific increase in the risk of ACL injury. The purpose of the study was to investigate sex-dependent changes in the KFM 0-70 from pre-adolescence to adolescence during a cutting maneuver (CM). Methods Kinematic and kinetic data during the CM task, performed before and after physical exertion, were recorded using a motion capture system and a force plate. A total of 293 team handball and soccer players, aged 9–12 years, were recruited. A number of those who continued sports participation ( n = 103) returned five years later to repeat the test procedure. Three mixed-model analysis of variance (ANOVA) for repeated measures tests were used to determine the effects of sex and age period on the KFM 0-70 (1: with no adjustment, 2: adjusted for repeated measurements, and 3: additionally adjusted with hip and knee joint frontal plane kinematics). Results Boys had significantly higher KFM 0-70 than girls at both age periods ( p