I got a little heady and wordy in my explanation here. Your lower back get tight from sitting all day as your hip flexors shorten and pull on the spine and cause hyper lordosis or anterior pelvic tilt. We combat this NOT by only stretching the anterior hips and psoas… we do it by using the glutes and hamstrings and hip extensors to lengthen the psoas. This video shows you how… This is extremely counter intuitive and why many people persist in lower back pain for years.