Given the disparity in anterior cruciate ligament (ACL) injury rates between dominant and non-dominant legs during single-leg and double-leg jump landings (SLJLs and DLJLs, respectively) in females, landing mechanics may differ across limbs and tasks. Furthermore, ACL injury risk stemming from peak kinetics is influenced by the knee flexion (KF) angle during force exertion. This study aimed to examine differences in sagittal plane landing mechanics between limbs during the SLJL and the DLJL in healthy females, with a specific focus on KF at peak kinetic values. Nineteen recreationally active females (age = 21.11 ± 3.28 yr; body height = 167.26 ± 7.26 cm, body mass = 67.28 ± 9.25 kg) were included. Sagittal plane biomechanics were recorded using a motion capture system interfaced with two force plates during the SLJL and the DLJL. Paired-sample t-tests were conducted to assess biomechanical differences between legs for both tasks. Limb asymmetries in KF at peak kinetic values were found between legs in healthy females. The non-dominant leg exhibited smaller KF at peak anterior tibial shear force (ATSF) than the dominant leg during the SLJL (p = 0.04, d = 0.49). During the DLJL, the dominant leg displayed smaller KF at peak knee extension moment (KEM) than the non-dominant leg (p = 0.03, d = 0.53). The findings indicate that females may have a higher ACL injury risk in the non-dominant leg during the SLJL, and in the dominant leg during the DLJL. These task-specific differences highlight that screenings should consider both limbs and landing types to enhance injury risk detection. Considering KF at peak kinetics when evaluating landing mechanics may enhance sensitivity and accuracy in identifying the leg at high risk for ACL injury.
