An incredible exercise to lengthen the hamstrings, spinal electors and glutes with a progressive loaded stretch. All the posterior chain muscles need to stabilise while lengthening which builds strength and mobility throughout a wide range of movement.
Start in a standing position on a box or a bench, toes must be on the bench/box not hanging over the edge. Use a kettle bell, plate or bar at a light weight and slowly work up from here, you do not need heavy weights.
Then tuck the pelvis in and hollow out the spine and from the head start relaxing down vertebra by vertebra. Push the bum back and as the weight reaches the feet, reach forward holding for a second before squeezing the glutes, resetting the spine and working slowly back up to a standing position. Working for low repetitions.