Diaphragmatic Breathing for Lifting: The Basics
This article discusses the topic of diaphragmatic breathing as it relates to lifting heavy loads. For a more basic overview of diaphragmatic breathing as an everyday practice, check out this video.

Diaphragmatic breathing involves breathing "into your belly." This is one of those phrases, similar to "sit up straight" or "lift with your legs," that we hear sometimes but are never really told what they mean or how to do them.
Breathing into your belly does not mean filling your stomach with air. It means breathing into your diaphragm, which is a large, dome-shaped muscle located between the lower part of the sternum (breastbone) and the ends of the lower ribs. As far as muscles go, it is kind of important: it allows us to breathe by expanding the ribcage.

Most of the time when we breathe, our breaths are somewhat short and the chest rises and falls with each breath. This is what's called "chest breathing."
In order to breathe into your diaphragm, however, breathing must involve movement at the area of the belly rather than at the chest. As you breathe in, the belly moves outward. This indicates that the diaphragm is expanding the lower ribs, creating a sort of air chamber.
By creating this air chamber while contracting the abdominal muscles, we create a state of "abdominal pressurization" that is extremely tight, stable, and sturdy. When lifting heavy weights that put direct or indirect load onto the spine, having this type of abdominal pressurization is vital for two reasons:
1) to protect the lower back,
and 2) to produce maximum force.
Studies by Dr Stuart McGill and others have shown that when the core is tightened in this way, it produces greater muscular responsiveness throughout the body. Dr. McGill compares this mechanism to a "guy wire system," similar to the rigging across a large sailboat. By maintaining tightness in the core, it helps produces greater tightness and responsiveness throughout the body, resulting in greater force. And if you can't produce adequate force, your lifts will be limited.
So, how is this done? There are, as I indicated, two parts to the type of diaphragmatic breathing we are doing. One is taking the breath itself. The second is engaging the core muscles.
First, the breathing. This involves taking a breath, either into your diaphragm or into your chest and then "pushing" it down into your diaphragm, and actually holding the breath for a certain duration to achieve maximal tightness,
Then comes engaging the core muscles. Once the breath is in the diaphragm, the lifter forcefully engages his or her core musculature: the abdominals, obliques, glutes, and spinal erectors. Then, the lift is executed. The breath is held during the first phase of the lift and slowly exhaled during the second phase in order to avoid losing abdominal pressure all at once.
For example, during a squat, the breath would be held on the way down and slowly exhaled on the way up.
The exhalation step is critical for making sure the breath is not held too long, which would cause dizziness, headache, or loss of consciousness.
The principle is to maintain the breath and the abdominal tightness at its peak when the spine is under the greatest amount of stress, and to exhale the air during the moment of greatest effort. As per our squat example, the lower back is most tempted to round forward on the way down. Having a pressurized core during this period is vital for that reason, to prevent that from happening.
Some more examples of how this method of breathing would be integrated into various lifts include: during an overhead press, the breath is taken right before raising the bar overhead, and slowly exhaled as the bar is lowered. During a bench press, the breath is taken right before the bar is lowered toward the chest and slowly exhaled as the bar is raised again. During a barbell row, the breath is taken while the bar is hanging below the lifter, who then forcefully (but under control) pulls the bar forward, before slowly exhaling and lowering the bar at the same time.
So what is the best means of achieving all of these interesting but odd little steps? The answer is practice and mindfulness, along with something called the Valsalva Maneuver.
You've done the maneuver countless times in your life, because it (or some variant of it) is involved in coughing, laughing, sneezing, and numerous other bodily functions. It involves forcing air out of the lungs through a closed airway. That is, the air is forcefully breathed out but it can't leave the body. This causes the abdominal muscles to tighten involuntarily.
Try this: put your hand on your belly and cough. You might feel your abdominal muscle suddenly tighten. This is a version of the valsalva maneuver: your body is trying to create forceful bursts of air to remove whatever is irritating or obstructing the airway.
When it comes to lifting, the trick is to be able to implement the valsalva maneuver voluntarily in order to create maximal core stabilization, or as much stabilization as we need. It produces what Dr. McGill calls that familiar "Hoik!" sound when you go to lift something heavy.
So, how to do it: take a breath---either into your belly or into your chest and press it down into your belly (so that your belly presses outward)---and attempt to breathe out while closing your airway in the back of the throat. This is the basic maneuver. Now your core is tight.
Further, mindfully engage (meaning flex, contract, tighten, harden, whatever) your abdominal muscles so that they are even tighter.
The final step, to go even farther, is to do what's called "bearing down," and this is exactly what is sounds like. Apply pressure to the muscles of your pelvic floor as though you are trying to initiate a bowel movement. Take the necessary precautions to avoid any unplanned incidents.
While holding all of this together---the breath, the valsalva maneuver, the contraction, and the bearing down---execute your lift as described above, by holding the breath when the spine is most under duress and slowly exhaling as the weight is returned to the starting position. It should all take no more than about two seconds.
Introducing this technique is an odd transition to make and should be done slowly, with light weight, until the various steps are integrated into a repeatable pattern. Do not rush the process; the amount of core tightness should be proportional to the amount of weight you are lifting.
A common question is, can I hold one breath throughout two or three reps? When it comes to squats and deadlifts, the answer is no, don't do that. Take a new breath for each repetition. Reset your breath and your core pressure between each rep. With presses like the bench press and the overhead press, you could maybe get away with it, but be mindful not to hold it too long or you'll get dizzy. Trust me.
There are a few caveats when utilizing diaphragmatic breathing with the Valsalva maneuver. At the moment the maneuver is activated, an increase in blood pressure can result. This is because the flow of blood returning to the heart (known as venous blood) is slowed. What this means is that the valsalva maneuver is generally considered contraindicated in anyone with a personal or family history of heart disease or hypertension. If you have such personal or family history, you will want to talk to your doctor and make sure heavy lifting using the valsalva maneuver is safe for you.
Additionally, a not-uncommon side effect of performing the valsalva maneuver regularly is hemorrhoids or hemorrhoid-like symptoms, due to the downward pressure placed on the lower trunk of the body. So that's something to be aware of. If this happens, it usually means you moved too fast. Move a little more slowly and don't bear down quite so hard. Build up to higher weights, when that level of bearing down is necessary, and you may be able to minimize these symptoms.
Another concern worth mentioning is that using this technique may make the belly look bigger. This is due to two things: the stretching of the abdominal muscle while the breath is held, and the thickening of the muscle itself as it grows stronger. Therefore, athletes who are oriented towards aesthetics---bodybuilders, physique or figure competitors, fitness models, any field where having a "tight waist" is an asset---may want to think twice about using it, or use it sparingly. (To my knowledge, it is possible to reverse this effect to an extent by performing an exercise called a "vacuum.")
This technique of diaphragmatic breathing is common among powerlifters and weightlifters both competitive and recreational. But, as a somewhat more casual lifter or worker-outer (or at least viewing yourself as one), you might be wondering why the average person would feel it necessary to utilize a technique that seems so complicated and potentially hazardous. Admittedly, it is not for everyone. But the answer is simple:
maximum safety + maximum force = maximum potential progress
This is what diaphragmatic breathing delivers. It can take you to the next level, plain and simple.
Prior to utilizing it, you may reach a point in your lifts at which progress will start to slow or stop altogether. Let's say you've perfected your form, worked out all of the muscular kinks, pains, and mobility issues, and worked backed up to your highest weights, but you still can't exceed them. This may be because your are unable to generate the necessary core stiffness and resulting force to move heavier loads that exceed your current limits while keeping your lower back safe.
The answer is diaphragmatic breathing. If it is done patiently and carefully, with a mind for the end-goal, and with a doctor's OK if you have a personal or family history of heart disease or hypertension, it is the best way to lift more weight, build functional core strength, and protect your lower back for the long term. Period.
If you're interested in implementing this technique, talk to your trainer.
:)))