The shoes that you attach to the bar of a steel cage with the corresponding hooks are nothing new, they were used as early as the 1970s. And even then, doctors and athletes warned that they were not for everyone, as hanging upside down can cause headaches for many people with health problems.
The purpose of these shoes is both therapeutic and gymnastic. By using these comfortable but firm and safe shoes, you will take care of the decompression of the spine, and will immediately feel relaxation in the shoulder girdle. Of course, you can also use these shoes for training: you can try doing sit-ups while hanging from the bar, and if you feel that your workout is too easy, you can add another kilogram or two of weights. While doing sit-ups, the torso is not the only part of the body doing all the work, but also the calves and thigh muscles, as the body will need to be stabilized on the bar.
The shoes and gravity combined thus give us the option of performing exercises that will be a real challenge for even the most capable athletes.