###### Abstract  
Loading characteristics and lower extremity injury mechanisms, such as the non-contact mechanism of cruciate ligament injury, differ between sexes. The Limb Support Moment (LSM) quantifies hip, knee, and ankle moment contribution to the net moment required to prevent limb collapse during deceleration tasks. In total, 10 males and 10 females performed single limb deceleration landings within three knee flexion ranges: 0-25\({}^{\circ}\), 25-50\({}^{\circ}\), and 50-75\({}^{\circ}\). Lower extremity joint moments and LSMs were calculated for all planes at initial contact (IC) through 50 ms. A two-way multivariate ANOVA compared LSMs and joint moments between sexes for all planes. Female LSMs were significantly greater at IC in the sagittal and transverse planes due to the generation of hip and ankle extensor moments and larger hip, knee, and ankle internal rotation moments. Males demonstrated significantly greater LSMs in the frontal plane due to the generation of hip abductor moments. Results suggest that females have a more rigid lower limb than males at landing, with less shock absorption capacity and greater potential for frontal plane collapse due to an unsupportive hip adductor moment. Quantifying the contribution of joint moments to limb support via LSMs suggests that there are landing characteristic sex differences, which may provide insight into injury disparity while guiding injury prevention/rehabilitation methodology. L  
and proprioception [10; 12; 13; 14]. Sex differences in loading characteristics are considered the product of biomechanical and neuromuscular control differences and their effects on multiple planes and on multiple joints [5; 8; 15; 16; 17; 18; 19; 20; 21; 22; 23]. Standardized in-vivo analysis tasks, such as landing from a jump [2; 10; 24; 25; 26; 27], cutting maneuvers [4; 28], or higher shear force tasks [29], have been used to investigate sex differences within lower extremity biomechanical factors linked to injuries such as ACL rupture. These tasks inherently assess a single plane and/or joint. Sagittal plane analyses of this nature have shown that females utilize their hip extensors less than males [4; 15], utilize less knee flexion during landings [1; 29; 30; 31; 32; 33], and demonstrate no significant difference versus males in ankle loading [26; 34]. Frontal plane analyses reveal that females generate greater hip adductor moments [24; 35], generate greater knee adductor moments, which may stem from the larger hip adductor moments [24; 28], and demonstrate greater frontal plane ankle aversion, which may elicit valgus knee stress and proximal tibial anterior translation [4; 28]. Transverse plane assessments are more limited, revealing that females generate greater hip internal rotation displacement during drop landings [27] and that knee and ankle rotation moments may play a role in injury for both sexes [36]. These findings suggest that there are sex differences in hip and ankle joint mechanics, which are related to the knee; however, these single plane-single joint results do not provide a means of determining the interactive relationship that each joint has on the entire limb. The Limb Support Moment (LSM) provides a means of quantifying this interactive relationship while identifying loading characteristic sex differences, which may potentially help to identify sources of sex disparity in injuries. The use of the Limb Support Moment (LSM) to represent the lower extremity as a three-component structure yields a model for making sex comparisons within a task not limited to a single plane or joint [37]. The LSM quantifies the contribution of hip, knee, and ankle moments as supportive or unsupportive to the net support moment, preventing limb collapse during rapid deceleration [37; 38]. The net LSM indicates whether the assessed limb is in a state of support or collapse, as defined by the polarity of the sum of the joint moments within a single plane, as defined in a right-hand orthogonal system [37].