According to different types, ranging from hundreds to thousands, there are many kinds, it is hard to say. Waist-twisting fitness equipment is stiff for the elderly, and the movement should be as slow and soft as possible when twisting the waist. Twisting the waist too fast will lead to small muscle strain around the spine, which will have adverse effects on the intervertebral disc and may lead to disc herniation. So when doing waist twisting, you should do what you can, don't twist yourself to the extreme, especially don't use too much force.