The main role of the triceps is as follows: 1. It can effectively play the role of elbow extension, the main source of strength in elbow extension is the triceps, through elbow extension the human body can do a series of activities, such as supporting the upper body, fighting, throwing, climbing, lifting heavy objects, etc., in this series of activities, all need strong straightening action, that is, the contraction of the triceps to complete. 2. The posterior extension of the shoulder joint can make our body do a better job of swinging the arm, as well as the shoulder joint to the back side of the extension, in order to grasp the back side of some objects. 3, can play an effective protective role, the long head of the triceps muscle on the left and right side of the trigeminal pore, respectively, the four side of the pore, its internal there are some important blood vessels, nerves through, these vascular nerves and in the deltoid and triceps muscle through the deep side, when the triceps muscle to provide adequate protection. The triceps muscle provides adequate protection for it. In addition, the triceps muscle provides adequate soft tissue support for the slightly inferior part of the triceps muscle, where the radial nerve passes internally, in order to prevent the radial nerve from relevant injuries.