Hello, my friend! Let me answer for you: the fullness and firmness of chest muscle exercise is one of the signs of youthful bodybuilding. Developed pectoral muscles make men look strong and burly, while women are more plump and lined. Strength training of chest muscles can also enhance cardiopulmonary function, correct bad posture such as chest-containing, make the chest bigger and change the chest circumference narrower. The pectoral muscle mainly includes pectoralis major, pectoralis minor and intercostal muscle. This exercise can be done by hand or instrument. 1. Exercise the chest muscle strength by hand, mainly push-ups, and develop the chest muscle by using your own weight and relying on forearm push. Push-ups can be carried out on the flat ground, or with hands and feet supported or loaded. Preparation posture: bend over, with your hands shoulder-width, arms straight, ankles close together, toes firmly on the ground, slightly raise your head, look forward, hold your chest out, tuck in your abdomen, and keep your body straight. Action: The arm bends gradually from the straight position. Bend your elbows and slowly move your body down to keep it parallel to the ground. After a short pause, pectoralis major contracts, and your arms are forced to straighten at the same time, thus propping up your body and returning to the ready posture. Pay attention to keep your body straight all the time during the action. The above actions are repeated about 10 times. After a certain degree of exercise, you can use handstand push-ups, high-legged push-ups, weight-bearing push-ups (putting some heavy objects on your back), narrow or wide support (deliberately narrowing or expanding the support distance between your hands), finger support and other actions to increase the difficulty and obtain greater exercise effect. Essentials; Always keep your chest out and abdomen in, and avoid incorrect postures such as sinking shoulders, shrugging shoulders, shrinking breasts, hunching your waist or lifting your hips. Function: Mainly develop pectoralis major, and also exercise the strength of triceps brachii and deltoid muscle. 2. Dumbbell exercise (1) Flying birds practice preparation posture: supine on a short bench with shoulder width (family can use three square benches instead), legs flexed, feet separated, arms straight, hands holding dumbbells, fists facing each other. Action: At the same time, both arms slowly fall from above to the body, and try to expand the chest as much as possible. After a short pause, contract the pectoralis major and arm muscles, so that the dumbbell can be slowly lifted from both sides to the chest along the original path, and the preparation posture can be restored. Repeat the above actions for about 20 times. In addition to supine position, birds can also move in standing position and inclined plate position (the angle of inclined plate is 30-60). Key points: when lying flat, the chest should be upright and the back muscles should be tightened. When the arm descends, the pectoralis major should be used to control the descent. After descending, pectoralis major is fully extended, and the speed of lifting and recovering is slightly faster than that of descending. After the arm is vertical, the pectoralis major still keeps trying to contract. Function: Mainly develop pectoralis major and deltoid muscle. (2) Standing posture: supine on a low stool, knees bent, feet apart, stepping on the ground, arms straight, hands holding dumbbells on legs. Action: the straight arm of the left upper limb forcibly lifts the dumbbell to the back of the head through the upward direction, and when the dumbbell is slightly lower than the body behind the head, it slowly returns to the side. Alternate left and right. Repeat the above actions for 20 times. Key points: Tighten the back and waist muscles, and control the descending speed with the strength of pectoralis major. Pull it up a little faster and then put it down evenly and slowly. When you start practicing, don't weigh too much dumbbells. Function: Developing serratus anterior muscle and shoulder and back muscle, and enlarging thoracic cavity at the same time are beneficial to increase vital capacity. 3. Preparation posture of the puller: Stand naturally with your feet shoulder-width. Before straightening, lift your arms horizontally and hold the puller with your palms facing each other. Action: the muscles of the chest and arms exert force, so that the arms are slowly pulled horizontally to both sides through the body to expand the chest until the arms are raised horizontally. Pause for a moment and slowly return to the preparation posture. Repeat the above actions for 20 times. Stretcher chest expansion can also be performed in supine position. Key points: stand at attention, move at medium speed, and pay attention. Function: Develop pectoralis major and triceps brachii, and expand chest cavity. 4. Barbell preparation posture: supine on a low stool, knees bent, feet apart, flat on the ground. Ask your partner or family to lift the barbell to your chest, with fists facing your eyes, and hold the barbell bar horizontally. Action: the muscles of the waist and abdomen contract, and the chest is lifted by inhalation, while the pectoralis major muscles contract. Push the barbell upward until the elbow joint is straight, pause for a moment, bend your arm and slowly put the barbell back on your chest, and bend your arm to relax your shoulders, so that the pectoralis major muscles can be fully extended and relaxed. The above actions are repeated 10 times. In addition to supine posture, this kind of exercise can also be carried out in reclining posture. The upper muscle of pectoralis major is developed in the upper oblique position, and the lower muscle of pectoralis major is developed in the lower oblique position. The grip modes are divided into narrow grip, middle grip and wide grip. Narrow grip develops the height of chest boat, while wide grip broadens pectoralis major. Essentials: the body should lie down smoothly, the barbell should descend slowly to avoid accidents, and the pectoralis major should give full play to its strength, not lend its strength. I hope my answer will satisfy you! (This answer is personal, please don't copy it. )