RecruitingBehavioural interventionSteps Towards Osteoarthritis PreventionOptimal knee joint loading, which refers to the forces acting on the knee caused by daily activities such as daily steps, plays an essential role in maintaining knee articular cartilage health and reducing the risk of osteoarthritis (OA). After anterior cruciate ligament reconstruction (ACLR), individuals take fewer daily steps as compared to uninjured controls resulting in insufficient knee joint loading to joint tissues, but it is unclear how changes in daily steps impact knee joint cartilage health in OA development. Therefore, the overall single arm, longitudinal pre-test post-test study objective is to determine the mechanistic links between knee joint loading as measured by daily steps and comprehensive magnetic resonance imaging (MRI) measures of knee joint cartilage health post-ACLR. The central hypothesis is that individuals post-ACLR who take low daily steps will demonstrate deconditioned, less resilient cartilage characterized by poor tibiofemoral cartilage composition and greater cartilage strain.