Sudden inability to bend over and pain when moving consider lumbar disc herniation, lumbar small joint disorder, lumbar sprain and other reasons. 1. Lumbar disc herniation: trauma caused by fibrous ring rupture acute disc herniation can cause sudden inability to bend over and pain when moving, through the lumbar spine MRI film can be clearly diagnosed. 2. Lumbar vertebral small joint disorder: due to long-term sedentary or poor posture can cause lumbar vertebral small joint disorder, synovial membrane jammed edema stimulation of nerve endings acute pain, inability to bend over, limited activities. 3. Lumbar sprain: sudden postural changes or lumbar external pull caused by lumbar pain, lumbar fixed in a position, can not move. Suddenly can not bend down a move on the pain need to go to the hospital orthopedics to see, diagnosis is clear after further treatment.