1, dumbbell bench press key exercise parts: pectoralis major, deltoid and triceps brachii. B. Starting posture: Lie on your back on a flat bench with your feet flat on the ground. Hold the dumbbell with your palms straight up. C. Action process: make the two straight arms open to both sides, slowly bend the arms, and the dumbbell falls vertically. When it reaches the lowest position, do push-ups and exhale when push-ups. Then push it to the open position and sit down. D. training points: don't arch your back and hips or hold your breath, which will make your muscles lose control and be dangerous. 2, lying dumbbell bird key exercise parts: pectoralis major and deltoid muscle. B. Starting posture: lie on your back on a flat bench, hold dumbbells in both hands, palms facing each other, and push up until your arms are straight and supported above your chest. C. Action process: Two hand-held dumbbells fall to both sides in parallel, with elbows slightly bent, until the muscles on both sides of the chest feel fully stretched, and the upper arms fall to the level below the shoulders. Take a deep breath when the dumbbell falls. Exhale when holding the bell and lifting it back to its original position. D. Training points: Dumbbells fall to both sides. If your arms are in a straight state, it is difficult for your chest muscles to get the feeling of stretching and muscle contraction. 3. The key exercise part of upward inclined dumbbell bench press is the upper part of pectoralis major, followed by the toe of deltoid muscle and triceps brachii. B. Starting posture: Lie on your back on a bench with an upward inclination of 35-45 degrees. C. Action process: Hold the dumbbell directly above the shoulder with both arms. Inhale when you put it down above the chest (near the clavicle). When descending to the lowest place, do push-ups and exhale when doing push-ups. D. Training points: During the training, focus the main strength on the pectoralis major, so that the pectoralis major is always in a state of tension. Triceps brachii as a secondary supplementary strength. 4. The key exercise parts of the upward inclined dumbbell bird: upper chest and deltoid muscle. B. Starting posture: lie on your back on an inclined bench, hold dumbbells in both hands, palms facing each other, and push up until your arms are straight. C. Action process: Two hand-held dumbbells fall to both sides in parallel, with elbows slightly bent, and the dumbbells fall to the muscles on both sides of the chest to feel fully stretched. Take a deep breath when the dumbbell falls. Exhale when holding the bell and lifting it back to its original position. D. training points: if the dumbbell falls to both sides and the arm is in a straight state, it is difficult for the chest muscles to feel stretching and muscle contraction. 5. The key exercise part of parallel bars is the lower part of pectoralis major, followed by triceps brachii and deltoid. B, starting position: the distance between the poles is better than the shoulder. Hold the pole with both hands as a straight arm support, hold your chest and abdomen, and keep your legs together, straighten and relax. C. Overstroke: Exhale, bend your elbows and arms, and lower your body until your arms bend to the lowest position. Your head should be led forward and your elbows should be abduction, so that the pectoralis major can be fully stretched. Inhale immediately, support your arms with the sudden contraction of pectoralis major muscle, and make your body rise until your arms are completely straight; When the upper arm exceeds the horizontal position of the bar, the hips are slightly retracted and the trunk is in a posture of "bow your head and hold your chest out". When the arm is straight, the pectoralis major is in a state of complete tightening. Repeat the exercise. D, training points: the action should be carried out slowly, and don't use the vibration of the body to help complete the action; Hold up quickly, hold out your chest, raise your head and abdomen, and don't shrug your shoulders; In order to increase the training intensity, you can carry out waist weight-bearing exercises.