The latissimus dorsi is located at the back of the waist and the outside of the chest, and it is the widest muscle in the human body. The developed latissimus dorsi is an inverted triangle from top to bottom. The latissimus dorsi muscle can make the upper arm adduction and pronation, the trunk pull up and the ribs lift up, so it is also an auxiliary inspiratory muscle. Besides latissimus dorsi, there are trapezius, rhomboid, teres major, teres minor, infraspinatus, supraspinatus and so on. The function of these muscles is to ensure the normal movement of scapula, neck and upper arm. The following is the action to exercise the back muscles. Pull-ups at the back of the neck, hands holding the horizontal bar at a distance, palms forward. Then use the contraction force of latissimus dorsi to pull the body up until the horizontal bar touches the back of the neck, stop for a while, then use the strength of latissimus dorsi to control the body, slowly put down your arms and straighten completely, and relax the whole body. Inhale when the pull-ups are up and exhale when they are down. Focus your mind on latissimus dorsi during exercise. The closer the horizontal bar is to the shoulder, the better the exercise effect. But it is also difficult to do so. Beginners don't have to be too demanding at first, as long as the headrest can touch the bar. When rowing, your feet are open, your knees are straight, your upper body leans forward parallel to the ground, the barbell is hung in front of your legs, your hands are facing forward, and the grip distance is shoulder width. With the force of latissimus dorsi contraction, the two arms first pull the barbell to the calf, then bend the arm to lift the barbell to the abdomen along the leg, the latissimus dorsi tightens and stops for a while, then control the barbell with the force of latissimus dorsi, and slowly fall down along the original route, returning to the starting position where the two arms hold the barbell droop. Inhale when lifting and exhale when falling, with emphasis on latissimus dorsi. This action is mainly to exercise latissimus dorsi. When doing movements, although the upper body leans forward, you should not hunch over and always keep a straight back posture. In practice, wide grip distance is beneficial to exercise latissimus dorsi near waist, while narrow grip distance is beneficial to exercise latissimus dorsi near shoulder. If you stand on a block of wood with a thickness of more than 20 cm or practice on a bench, the barbell can be put lower, which can fully lengthen the latissimus dorsi and help the latissimus dorsi to expand. When rowing with one arm, the right (left) hand holds the dumbbell, the right (left) leg stands on the board with a thickness of 15-20cm, the left (right) leg kneels on the bench, the left (right) hand stool keeps the body balanced, the upper body leans forward, and the right (left) arm naturally droops. Then use the contraction force of latissimus dorsi to lift the dumbbell along one side of the body until it can no longer be lifted, paused and put back into the one-arm drooping posture. Inhale when lifting, and exhale when falling. This action is mainly to increase the thickness of the upper back muscle and exercise the rhomboid muscle in the deep trapezius muscle. Focus on the latissimus dorsi when doing the action. Stand with your legs on the board, so that the bell arm can hang lower and the back muscles can be stretched more fully and contracted better. Reverse bow practice prone on the bench, close to the bench below the waist, let your partner press your legs at the end of the bench, or fix your legs with broadband. Cross your hands and fingers behind your neck, lean forward with your head below the stool. Then, using the contraction force of sacrospinous muscles on both sides of the spine, the upper body is lifted upward to form an anti-bow shape, and then it stops for a while and then slowly falls. Inhale when lifting, bend forward and exhale when falling. When exercising, the mind should focus on the sacrospinous muscle (also known as the trunk vertical muscle). Keep your head up and your chest up when you lift your upper body. In order to increase the intensity of exercise, you can hold barbell pieces or sandbags in both hands and put them behind your head when doing actions.