The main reason for the asymmetry between the left and right chests is due to long-term unilateral activity and unilateral overexertion. The overexertion side of the pectoral muscle gets more training, so the pectoral muscle is more developed, while the other side gets less training, thus forming the deformity that the pectoral muscle is underdeveloped. The training method of self-correction is:

First, lateral push-ups. The body is prone, and the arms are straight and vertical to the ground to support the body. The distance between hands is about shoulder width. Chest out, abdomen in, waist in, legs together straight, toes on the ground, whole body straight. Exhale immediately, bend your arms so that your body's center of gravity falls on your weak chest. Consciously reduce the workload of the chest muscles, spread the elbows outward, bend the arms to the lowest position, and pause for 2 ~ 3 seconds. Then inhale, slowly contract the pectoralis major muscle, and at the same time extend the arm until the arm straightens back. Repeat 10 ~ 12 times and practice 3 groups.

Second, the parallel bars bend and stretch. Hold the parallel bars with your arms straight, chest out and abdomen in, legs together to relax and droop. Exhale immediately, the center of gravity of the body drops to the weak chest side, and the workload of the weak pectoral muscle is deliberately increased until the arms are bent to the deepest degree and the elbows are abduction, so that the pectoralis major muscle is fully extended and paused for 2 ~ 3 seconds. Then inhale and support your arms, and your body will rise until your arms are completely straight, so that your body will return to the straight arm support posture. Repeat 8 ~ 10 times and practice 3 groups.

Third, the supine side is recommended. Lie on your back on a bench or bench with your shoulders and arms touching the bench surface. Keeping your back away from the countertop is "orthopedic". Chest out, shoulders down. Hold the handrail with your palms up. Put the weight of the barbell on one side of the underdeveloped chest, and the grip distance is shoulder width. Put the barbell bar on the nipple of the chest. Then inhale, push the barbell up with your arms, straighten your arms and pause for 2 ~ 3 seconds. Then exhale and slowly put down the barbell to recover. Repeat 10 ~ 12 times and practice 3 groups.

Fourth, make a supine head with one arm with underdeveloped chest and pull it up. Lie on your back on the stool, with your legs apart, your feet on the ground, hold the dumbbell in one hand, straighten your arms, and put the dumbbell on your thigh. Exhale immediately, lift the dumbbell with your arms straight, fall back to the maximum through your chest and head, pause for 2 seconds, then inhale, and then pull the dumbbell up hard and recover through the original path. Repeat 10 ~ 12 times and practice 3 groups.

5. Use the arm with underdeveloped chest as a pimp. Fix the tape over your shoulders, lift it obliquely with one arm, and hold the movable end of the tape. Inhale immediately, and with the contraction force of pectoralis major, pull the movable end of the adhesive tape downward and inward to the front of the lower abdomen. At this point, the weak pectoralis major should feel completely taut and pause for 2 ~ 3 seconds. Then breathe, and then relax. Repeat 10 ~ 12 times and practice 3 groups.

【 Description 】 With the above correction training method, in addition to one-arm unilateral training, the weight of barbells and dumbbells and the tension of thongs should be concentrated on the underdeveloped chest side, which can strengthen the training of underdeveloped chest muscles and achieve the purpose of correction.