The prevalence of traumatic knee injury in sport is immense. Most injuries are due to an individual's own movement, such that direct contact with the knee did not occur. The study of anterior cruciate ligament (ACL) injury provides a great model to understand the neuromuscular consequences that contribute to a decline in physical activity, elevated risk for secondary injury, and the development of knee osteoarthritis following injury. The goal of this research is to improve long term outcomes following traumatic injury and sustain physical activity through the lifespan.