Hanging on a chair bends easily. Barbell is mainly because the middle bar is easy to bend. Generally speaking, when not in use, it is recommended to take down the discs on both sides and not hang them all the time. Especially in some gyms, many discs have been hung on them. After a long time, it is easier to bend. But after a long time, there will always be a slight bending of the middle bar, and this bending will be aggravated with use.