This study examines how wearing a brace changes physical performance in males and females who have undergone ACL reconstruction surgery. Subjects will perform several running, jumping, and hopping tasks both with and without a custom-fit functional knee brace. Subjects are currently being recruited for the study. Testing will be done on subjects will have undergone ACL reconstruction surgery and will be within three weeks of returning to sport-related activities. Subjects who have undergone ACL reconstruction surgery but have not yet returned to sports are encouraged to contact the lab so that we can schedule testing at the time of return to sport. Knee braces will be provided for subjects that meet all study criteria. Testing will take place in the Granata Lab during two separate sessions three months apart, with each session lasting about one hour. Subjects will be compensated $20 for each session. Please email us or call us at (540) 231-4294 if you are interested in participating in this study.