During the whole process, the arm is pushed upward by the contraction force of the pectoralis major, and after reaching the peak of the contraction of the pectoralis major, it pauses for a while, then keeps the elbow slightly flexed after pushing upward, and then the arm slowly returns to the initial position by the control force of the pectoralis major.

Sitting chest clamp: put the body on the armchair, so that the head and the whole back are always close to the backrest cushion, tighten the waist and abdomen, and hold out the chest. During the whole movement, the arm should be spread backwards as far as possible, with the elbow slightly bent, and then the arm should be clamped inward by the contraction force of the pectoralis major, and finally the pectoralis major reaches the peak of contraction, and then stop for a while. Then use the control force of pectoralis major to slowly spread your arms to both sides.

Push the shoulder when sitting on the equipment: put the body on the equipment chair, so that the head and the whole back are always close to the backrest pad, tighten the waist and abdomen, and hold out the chest. Hold the handle of the instrument with both hands. Concentrate the strength of deltoid muscle to push up the weight of load. Push up quickly during the movement, keep the elbow slightly flexed when reaching the apex, and stop 1 sec. Slowly lose weight and control your weight with the control of deltoid muscle.

Sitting posture and equipment lateral lifting: sit on the equipment stool, hold your chest out and abdomen close to the cushion, bend your elbow and hold the equipment arm, and put your forearm under the equipment arm, as for your sides. During the action, concentrate the force of the middle bundle of deltoid muscle to lift the instrument arm to the same plane as wrist, elbow and shoulder, pause for a moment, and then slowly return to the starting position.

Sitting posture of the instrument pulls down the back: hold your chest out, tighten your waist and abdomen, sit and climb, hold the instrument pull rod with both hands, fully raise your shoulders, and fully extend your pectoralis major. Concentrate the contraction force of latissimus dorsi, so that the pull rod can be pulled down to the chest, clavicle and nipple. Try to make the shoulder blades on both sides of the back close together and touch each other, so that the latissimus dorsi is at the peak position of contraction, and then slowly restore the pull rod to its original position.