Osteoarthritis is a prevalent and debilitating joint disease. The global prevalence of osteoarthritis is estimated to be 3.6-4.1% of the global population, making it the 11th highest contributor to global disability. Osteoarthritis most commonly occurs in the medial tibiofemoral compartment of the knee. Inappropriate knee loading, during daily activities, is believed to be a principle cause of knee osteoarthritis. Moreover, individuals who have sustained anterior cruciate ligament (ACL) rupture and reconstruction (ACLR) are at particularly high risk of onset of knee OA in the near future. Within 12 years following ACL injury approximately 50% of people will develop knee OA. Worse still, many individuals who have sustained an ACL injury show signs of early knee degeneration as little as 4-5 years post- surgery. The question arises, what is it about ACL injury that results in such high risk of future OA onset? Individuals with ACLR have abnormal gait biomechanics and muscle activation patterns, which may influence the knee contact forces. As well, the autograft donor muscles are often impaired following harvesting. This muscle impairment also likely influences the knee contact forces. However, what links exist between the altered knee contact forces and degeneration of the articular tissues have not been established. To date, there are no literature reports of the knee contact forces during both daily gait tasks and sporting movements. Likewise, an investigation of the differences in the knee contact forces between ACLR and healthy individuals during different movement tasks has not been performed. Finally, the literature lacks an assessment of the relationships between the tibiofemoral contact forces that arise during daily activity and the structural health of the articular tissues in the knees of ACLR individuals.