I have been using the horizontal bar on the door for half a year and have never had any problems. But I don’t know what happened today. I feel like the rubber has worn out and it fell off when I reached the highest point of my pull-ups! When I got up, I felt fine and didn't touch my head. However, my elbow joints were directly touching the ground. I rested for about 5 minutes. Both elbows hurt so much! I was so scared that I thought the bone was cracked. Later, when I went to the hospital, the doctor told me that it was a closed injury to the elbow joint caused by direct violence. It was not serious, but I would not be able to do upper limb exercises for at least half a month. I learned this from my own experience. ! I would also advise everyone not to buy this kind of thing. It will only delay your training. If you knock your head or get a crack in your elbow or waist, or even become disabled for the rest of your life, it will be a waste. .