Anterior cruciate ligament (ACL) injuries are widely studied, yet incidence remains high. These injuries are not only costly, but also place an athlete at increased risk of re-injury and knee osteoarthritis later in life. Although non-contact in nature, movements such as jump landings are a common mechanism for these types of injuries. The purpose of the studies described in this dissertation was to provide insight into factors that may increase ACL injury using basic, but relevant movements and screening tools. In the first study, ACL injury risk factors in ACLreconstructed individuals were compared in the injured vs. non-injured leg and with healthy individuals during a functional, self-initiated jumping task. The injured leg displayed higher ankle inversion angles than the non-injured leg at both the lower (p = 0.006) and higher jump heights (p = 0.020). Higher ankle inversion ankles may indicate that a previous ACL injury could place an athlete at increased risk of ankle sprain and potentially knee re-injury. In the second study, the Star Excursion Balance Test (SEBT) was utilized to test if the reach directions measured using this simple screening tool correlate with ACL injury risk factors. Minimum knee flexion angle, maximum knee flexion angle, and maximum hip flexion angle were higher for the higher performing group in the anterior, lateral, and posterolateral SEBT reach directions during 30 cm and maximum height jump landings (Cohen’s d medium effect sizes 0.553-0.739). These results indicate that the SEBT may be potentially predictive of sagittal plane kinematic ACL risk factors, but not necessarily frontal plane or kinetic risk factors. The aim of the third study was to determine if higher body mass index (BMI) corresponds with increased ACL risk factors and poorer performance on the SEBT. Maximum hip abduction and hip extension moments normalized by body mass were higher for the higher BMI group during maximum height jump landings (Cohen’s d medium effect sizes 0.622, 0.604). The anterior SEBT reach direction was shorter for the higher BMI group compared to the lower BMI group (Cohen’s d medium effect size 0.683). While the higher BMI group demonstrated poorer performance in the anterior SEBT, higher hip abduction and extension moments during jump landings may be protective mechanisms rather than increasing risk of ACL injury. In summary, different changes in ACL risk factors were found at different joints when considering different participant characteristics: previous ACL injury (ankle), SEBT performance (knee), and BMI (hip). Further study of the SEBT as a potential ACL injury risk screening tool is recommended with more challenging directional jump landings involving decision making and including athletes with a wider range of BMI.