Lower back self-myofascial release (SMR) is a self-administered soft-tissue treatment, usually using a foam roller, lacrosse ball, or other "trigger point" massage tool. By applying pressure strategically to the quadratus lumborum or spinal erector (erector spinae) muscles of the lower back, some people find they can cause this often painful and tight area to relax or "release." Lower back SMR is often accompanied by SMR on the glutes or piriformis muscles, or by stretches that target the piriformis or hips. However, some people find that SMR on the lower back can aggravate existing pain or injury, so be cautious when performing it.