Before using the waist extension frame, warm up properly. Stand with your back to the machine, hold the armrests on both sides, and slowly bend backward. Hold for 5-10 seconds before returning to the starting position. Precautions include controlling the torsion amplitude, not too fast, hands do not leave the handle, and slowly lift the upper body to prevent injury. There are pathologists who need a doctor's consent, and children who need adult care. If you feel unwell, stop immediately and consult a doctor. Only the correct and scientific use of the extension frame can effectively exercise."