 This is a case series to assess the running mechanics following ACL surgery using both standard and body weight supported treadmill. Patients who are referred to Westerville following an ACL reconstruction surgery will be offered the opportunity to participate in this study. Patients will begin their standard protocol for the first 3-4 weeks before being approached to participate in this study. At this time, if they are progressing well through their protocol, they will be approached and asked if they would like information regarding this study. After explaining the study and answering any patient or parent questions, informed consent and assent will be obtained for those individuals wishing to participate. The participants will be screened to see if they meet the inclusion criteria at this time. If the patient meets the criteria and is agreeable to participate in this study, standard protocol will continue to be followed until week six. Standard care will continue for all treatments excepts four visits, occuring during weeks 6,8,10,and 12, where a video recording of running gait mechanics will be performed to analysis biomechanics throughout the rehabilitation process. 