This course describes lumbar extensor release and lengthening, commonly referred to as low back foam rolling, erector spinae foam rolling, low back or erector spinae release with ball, low back stretching, and lumbar mobility techniques. Although terms like tight muscle, erector spinae muscle tightness, tight lumbar muscles, tight back, and stiff back are commonly used, it may be more accurate to label these muscles as prone to over-activity (e.g. hypertonic, phasic). Performing lumbar extensor (erector spinae, latissimus dorsi, psoas, and iliacus) 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 erector spinae, latissimus dorsi, psoas, and iliacus muscles, mobilizing the thoracic spine, lumbar spine, and sacroiliac joints (e.g. open books), and integrating a child’s pose stretch (latissimus dorsi and erector spinae stretch), and kneeling hip flexor stretch (psoas and iliacus stretch), is likely to improve lumbar (spine) and hip mobility and improve the effectiveness of exercises like quadrupeds, glute bridges, gluteus medius clams, deadlift touchdowns, etc.