Different sizes of 8-shaped rings bear different tensile forces. Take 10 as an example, the tensile force of 10 is 10kg, that of 12 is 5kg, and that of No.8 is 15kg.
The advantage of stretcher exercise is that biceps brachii is a muscle with two muscle heads, and its main function is to bend the arm. When you bend your arm, you will also use another muscle-the brachialis muscle. However, only when doing some forearm lifting exercises, such as bending the high-position puller or anti-high-position puller toys, can the brachial muscles be fully exercised. In addition, the flexor humeri, the main muscle in the upper forearm, also plays a lot of roles in arm flexion. The flexor humeri can be strengthened by lateral bending of the stretcher.