This course describes tibial external rotator release and lengthening, commonly referred to as tibial external rotator foam rolling, tibial external rotator foam rolling, tibial external rotator release with ball, tibial external rotator stretching, or knee mobility techniques. Although terms like muscle tightness, tight hips, tight tibial external rotators, tensor fascia lata (TFL) tightness, a tight biceps femoris (hamstring) muscle, etc., are commonly used, it may be more accurate to label these muscles as prone to over-activity (e.g. hypertonic, phasic). Performing tibial external rotator release and lengthening techniques to increase mobility prior to activation, integration, and strengthening techniques may significantly enhance rehabilitation and performance programs. In practice, the release of the tensor fascia latae (TFL), vastus lateralis, biceps femoris, and lateral gastrocnemius (calf), mobilizing the knee joint, and integrating a kneeling hip flexor stretch (TFL stretch), and modified calf stretch (gastrocnemius) is likely to improve knee mobility and improve the effectiveness of exercises like terminal knee extensions (TKE's), deadlift touchdowns, isolated tibial internal rotator activation, etc.