It can exercise arm muscles and avoid arm fat relaxation.
When the arm stretches up and down, the muscles of the upper arm will feel pain because of stretching, which is normal! Because the muscles of the upper arm are almost always in a state of relaxation and sagging, they have not been exercised. When you suddenly stretch, you will feel pain. Practice a few more times, and the pain will gradually ease.
In addition, when stretching the elastic rope, the muscles of the shoulders, neck and back will also feel nervous, and people who often work at their desks will feel even more nervous. This is also normal, because the muscles of the shoulder and neck are closely connected with the muscles of the big arm.