Lower Spine problems Forward bends are riskier if you have tendency to bend from the waist rather than the hip joints. People with tight hamstrings round their back so that they can go deeper into the pose. When the lower back rounds, the front portions of the lumbar vertebrae get compressed. The disks between the vertebrae are pushed backwards, compressing nearby spinal nerves. This nerve compression is a common cause of sciatica pain which can radiate all the way down to the legs.
Solution: In seated forward fold, use a folded blanket, or a bolster/pillow to elevate hips so that you get a natural inward curve in the lumbar spine. Another option is to slightly bend your knees. This takes the pressure off your hamstrings creating space for pelvis to tip forward. Another remedy for a rounded lower back is to use a strap or a belt. Hold the strap over the balls of your feet and stay upright with spine elongated.
In standing forward bend, bend your knees to release the hamstrings. Standing forward bend is less risky than seated forward fold as gravity tends to create an opening between the vertebrae. Placing your hands on the blocks in standing forward bend is also helpful.
Reciprocal inhibition is another technique to release tension from lumbar spine. As you engage abdominal muscles by bringing navel towards the spine during exhale, the antagonist muscles in the back are relaxed.