Preventing Posttraumatic Osteoarthritis With Physical Activity Promotion

Inclusion Criteria Participants will be included if they: * Provide informed consent and sign a HIPPA form prior to any study procedures are performed * Have completed all other formal physical therapy and therapeutic exercise regimens, and will not be engaging in any other formal therapy for their ACLR during the study * Are between the ages of 18 and 35. * Underwent an ACLR no earlier than 6 months and no later than 5 years prior to enrollment. * Demonstrate \< 8,000 steps per day during the screening phase of the study as assessed using the Actigraph GT9X Link monitor. * Demonstrate clinically relevant-knee symptoms, defined as a Knee Injury and Osteoarthritis Outcomes Score (KOOS) quality of life subscale \< 72.2 Exclusion Criteria Participants will be excluded if: * The participant underwent an ACLR revision surgery due to a previous ACL graft injury. * Multiple ligament surgery was indicated at the time of ACLR surgery. * A lower extremity fracture was suffered during the ACL injury. * The participant has been diagnosed with osteoarthritis in either knee * They have a cochlear implant, metal in body, claustrophobia, or history of seizures.