My clients often note the bizarre sound I make when I demonstrate a movement. It's a sharp "TSSST!" sound that many have never heard before. I force air out between my teeth at the completion of every rep and many claim it sounds like I have suddenly sprung a leak. This is diaphragmic breathing at it's finest and something everyone who wants to be strong, faster, hotter, or just more pain free needs to learn.
What's Going On
Let's review the concepts of tension and your core. If you recall, your body is just a bag of meat with some internal scaffolding. The place on your body with the least scaffolding is the area from your pelvis to your ribs that coincidentally houses your lumbar spine. It's your "core" and it's really just a ball of Jello with your spine going through it like a bendy straw. Your body depends on the coordination and strength of your core muscles (pelvic floor muscles on bottom, transversus abdominis, multifidus, internal and external obliques, rectus abdominis, erector spinae (sacrospinalis) especially the longissimus thoracis, and the diaphragm on top) to protect your organs and delicate spinal chord. And because this job is so important, it has left your conscious brain mostly out of it. That's right, the majority of the muscles in your core are not under not under your direct control. Breathing deep by engaging your diaphragm is the way that we have to trick the deep musculature of the core, especially the pelvic floor, to engage and the create tension when we need to pick up something heavy.
How You Breathe
When I tell people to "take a deep breath," 99% of them puff up their chest, raise their shoulders, suck in their gut, and inhale a little oxygen. This is called "panic breathing" and it mostly utilizes the trapezius, sternocleidomastoid, scalene, external intercostal muscles. These are the muscles that most people say they "feel tension" in. The chronic result is pain, shallow breathing, and a locked up thoracic spine. You looked puffed up and immobile. Not hot. But there's a cure!
Deep and Wide
Lie down on your stomach with your face resting on your hands. Take a deep breath and fill your stomach with air. You will feel your tummy push down on the ground, but should not feel your chest push down. That's breathing deep. Now take another breath, filling you stomach and try to push it out the sides of your tummy. I place my fingers on a client's sides and ask them to "push out." That's breathing wide. Now repeat 50 times.
What Will Happen
If you integrate diaphragmic breathing into your every day life, a lot of great things will happen. You will get more general core engagement when you need it (like lifting heavy things or running quickly). You will begin to relax those "panic breath" muscles reducing the pain and cramping that generally occurs in that area. You will stand up straighter. You will be stronger. You will be hotter. You will be taller. I'm serious about that last one. On top of looking taller, you will actually be a few centimeters taller. What other exercise can promise that?