Specifically, stand on your knees, hold your arms on your thighs, empty your lungs and abdomen, and then push your legs with your arms with your abdominal muscles. You will see the middle abdominal muscles bulging, as shown in Figure 2. Then you try to change the force exerted by your arm on your thigh, slowly from left to right, then slowly from right to left, and then try to use the same force on both sides but different abdominal muscles. In this way, you can do both horizontal and vertical waves, but at first the tumbling is definitely not smooth, because I am not familiar with the feeling of force transmission, so I just need to practice more. As for posture, you can also change it to meditation posture when you master it, and put your arms on the ground in front of your knees. In short, arm support is the key. This thing, I just watched a video for a few minutes (although it didn't roll smoothly at first), but I practiced it many times and found that it actually had a general effect on the diaphragm, and personally felt that it had a better effect on stretching the lungs. Mainly because you feel bloating after exhaling. In fact, the negative pressure of the lungs caused by the enlargement of the chest has pulled the diaphragm up, and the diaphragm has been well stretched. At this time, the diaphragm is pulled down with the abdominal muscles, and the force is more on the lungs than on the diaphragm. The diaphragm was just caught in the middle without any force. You can really practice this if you want to stretch your lungs. In fact, we should make it clear that some exercises are not necessarily completely related to the training of lungs and diaphragm, some are stretching diaphragm, some are stretching lungs, and some are effective at the same time. First, let's relax and stretch, with dozens of breaths like a puppy gasping, and then I mentioned several groups of empty lung abdomen and whole lung chest expansion exercises (as long as they are not packaged, exaggerated and not harmful to the body). The next step is strength training, which uses fists to block the mouth and act as a pipe, and only uses abdominal breathing to blow and inhale as much as possible. The tightness of your fist determines your suction. Personally, I control this strength to be similar to blowing a very hard balloon, or an airplane neck pillow blocked in the opposite direction, which may be stronger than that. The key is that this strength can make you take a breath in the middle of blowing and inhaling, so as not to make yourself dizzy. Because the blowing time is longer, you should control it yourself. After finishing, the diaphragm is sour and refreshing. I come twice a day, and the effect is very good. Not only exercise diaphragm, but also fully open alveoli and improve vital capacity. If you want to practice at low cost, there are many respiratory muscle trainers on Taobao. You can buy one for use. Anyway, I always blow the plane neck pillow at home when I'm free. Even directly inhale from the inside and repeat, create an anoxic environment for yourself, and grasp the amount, which can effectively exercise vital capacity and diaphragm. At first, I didn't snorkel in the pool. If I swim in the air, my diaphragm will be a little painful (about 30% air) and my diaphragm will be stretched. I've practiced a lot, and I've been swimming recently. It doesn't hurt at all.