Anterior cruciate ligament (ACL) injuries are common in females, and most non-contact ACL injuries occur during landing or cutting movements. Also, fatigue has been linked to an increased risk of injury. Accordingly, significantly more injuries occur during the latter portions of game performance, according to several epidemiological studies. However, a scarce amount of research exists regarding the effects of neuromuscular fatigue on landing biomechanics. We surmised that FL would cause abnormal lower extremity biomechanics. PURPOSE: To determine if a 60-second continuous bout of jumping affects lower extremity landing biomechanics in females. METHODS: Recreational female athletes (n=10; 63.9±6.5kg, 170.5±3.1cm) participated in this study. Participants performed established fatigue protocol: double leg vertical jumps every three seconds for 60 seconds. Participants were required to touch a suspended horizontal bar during each jump, with the bar height set by having participants hang from the bar and adjusting it until the height from the midpoint of the lateral malleolus to the ground was 0.4 m. The first three consecutive jumps from the first and last 10 seconds were chosen for data analysis. Reflective marker coordinates were reconstructed from locations captured from 7 cameras (240 Hz). Dominant-side lower extremity angular joint kinematics and ground reaction forces (GRF: 1,200 Hz) were compared between the non-fatigue landings (NFL) and fatigue landings (FL) using paired t-tests (p<.05). RESULTS: FL, compared to NFL, resulted in increased knee abduction angle (1.6±3.9° and 0.6±2.8°) and decreased knee flexion angle (2.7±5.2° and 4.0±6.3°) at initial contact (IC). An increased trunk maximum flexion angle (15.5±7.6° and 10.0±5.2°) and knee flexion displacement (58.7±12.8° and 55.6±13.6°) also occurred. Additionally, FL also resulted in a reduction in vertical GRF peak magnitude (1.47±0.24 N[BULLET OPERATOR]kg-1 and 1.75±0.26 N[BULLET OPERATOR]kg-1). CONCLUSION: At IC, both an extended knee position and greater knee abduction angle have been associated with an increase in ACL injury risk and loading. However, a decrease in peak vertical GRF and increased trunk flexion angle and knee flexion displacement are factors that decrease ACL injury risk and loading and may be adaptation strategies to protect the knee when fatigued.