To do this stretch the stretcher is seated with their legs extended away from their body, with their knees slightly bent. Ths stretcher leans forward as far as the can go pain-free, bending at the hips. The partner places their hands on the stretchers lower back and provideds resistence. The stretcher then attempts to extend their spine, that is lean backwards. The stretcher then inhales deeply maintaining their spine at the original position. Apon exhaling the stretcher then contracts their rectus abdominis and psoas to bend futher forward.
Images from www.exrx.com