Breathing Technique in Gym Training

Julius Granlund

M.Sc Exercise Science (Exercise Physiology), University of Jyväskylä

Tapio Tulenheimo

M.Sc Exercise Science (Exercise Physiology), University of Jyväskylä

Co-written by Tapio Tulenheimo & Julius Granlund.
In this article, we will discuss and provide simple guidance on how to breathe and engage your core correctly during gym exercises. This is important, especially when it comes to movements like deadlifts, squats, and other exercises that require core support. Proper breathing technique enhances both the safety of lifting and the amount of weight lifted (1, 2).
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Figure 1. Source.

What is it about?

Proper breathing and tightening the core are among the most important techniques in the gym. With good breathing technique, training becomes much more safe and motivating, as your technique remains controlled and supportive, and the weights feel lighter. In contrast, suboptimal breathing technique exposes you to the risk of injuries, especially in the lower back (1), makes movements more difficult and unstable, and limits force output (2).

In strength training, correct breathing is achieved through what is known as diaphragmatic breathing, combined with breath holding (the "Valsalva maneuver") and core engagement. These techniques maximize the internal pressure in both the abdominal and thoracic cavities. These pressures, among other things, provide support to the spine (3). The tighter your core and spine are, the more effectively force can be transmitted, as it is better conveyed through resilient structures. Higher internal abdominal pressure directly increases the power output of muscles such as the hip extensors (glutes, hamstrings, adductors) for example (2).

The role of breathing technique is particularly important in multi-joint movements and especially when the spine is under load. Such exercises include, for example, deadlifts, squats, and overhead presses. Breathing technique is also a crucial factor whenever you work with heavy loads, regardless of the specific exercise. In isolation exercises, such as bicep curls, this is often not necessary to consider. This article primarily addresses the topic of breathing in large multi-joint movements.

Proper breathing and core engagement before each repetition can be summarized as follows (Note: All steps will be explained in more detail later):
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1. Take a deep breath (imagine inhaling towards your abdomen - this is also known as diaphragmatic breathing)
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2. Perform the Valsalva maneuver (i.e., hold your breath and exhale forcefully against a closed glottis). Simultaneously, engage your entire core.

3. Hold your breath and maintain tightness throughout the entire repetition.

Let's first take a closer look at how this pressure supports the core and spine. Then, we will examine diaphragmatic breathing and the Valsalva maneuver, followed by a discussion of core engagement.

Internal pressure in the thoracic and abdominal cavities supports the mid-torso and spine

The thoracic cavity consists of the area enclosed by the ribcage, within which the lungs operate. The abdominal cavity, on the other hand, refers to the area bounded by the diaphragm and the pelvis. The diaphragm is the organ that separates these cavities from each other. The pressure within these cavities is regulated by the amount of inhaled air, the expansion of the lungs, and the movement of the diaphragm. The thoracic cavity can be "closed," and air can be held inside by holding one's breath, thus allowing a situation in which the pressures in the thoracic and abdominal cavities can be increased and maintained.

Figure 2: Position of the thoracic cavity, diaphragm and abdominal cavity. (Source)

Let's examine the importance of pressure using the example of a soda can: When the can is empty, it's easy to crush because there is no pressure inside the can. When the can is full and sealed, the internal pressure is high, and crushing it together is much more difficult (in fact, it requires a force of about 350kg). So it is not the thin aluminium shell that makes the can strong, but the pressure inside - the internal pressure turns a weaker structure into a strong one.
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Figure 3. We want our bodies to be like soda cans: High internal pressure keeps the structure tight. So, we aim to maximize this pressure to produce more force and lift securely. Proper breathing technique and core engagement enable more efficient transmission of strength.

Performing the breathing technique - diaphragmatic breathing, the Valsalva maneuver, and core engagement.

Diaphragmatic breathing
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First, let's briefly examine the anatomy of normal resting respiration.
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In inhalation, the primary responsibility lies with the diaphragm, which contracts and moves downward, expanding the thoracic cavity, allowing a greater flow of air into the lungs. Simultaneously, as the diaphragm moves downward, the internal pressure in the abdominal cavity increases. During inhalation, the external intercostal muscles also contract, lifting the ribcage upward, further expanding the thoracic cavity. Exhalation occurs as the respiratory muscles relax, and the diaphragm moves back upward, reducing the volume of the thoracic cavity. In active exhalation, the internal intercostal muscles contract, pulling the ribcage downwards.

In diaphragmatic breathing, uring the inhalation phase, the emphasis is on the contraction and downward movement of the diaphragm, which expands the volume of the lungs. As a result, the abdominal area expands forward and to the sides. This increases the internal pressure within the abdominal cavity more than the typical "chest breathing." Watch the video on diaphragmatic and chest breathing below.
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As a side note, the breathing pattern that emphasizes diaphragmatic breathing is beneficial to learn for daily life as well because it makes lung function and gas exchange within the lungs more efficient. This can lower heart rate and blood pressure compared to more shallow breathing.
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Instructions for diaphragmatic breathing: Take a deep breath "towards the abdomen," not "towards the chest." When inhaling, especially the front part of the abdomen should expand (see the upper video). Note: Although the emphasis is on the expansion of the abdominal area in breathing, the chest area often also rises slightly, especially when taking in a lot of oxygen.

Valsalva Maneuver:

In the Valsalva maneuver, a strong exhale is performed against a closed glottis (as shown in Figure 4). This technique keeps the oxygen in the lungs, increasing the internal pressure in the thoracic and abdominal cavities. This can be compared to the closed soda can mentioned earlier - when the glottis is closed, pressure remains inside.

Figure 4. In the Valsalva maneuver, the glottis is closed after inhalation, and an exhale is performed against the closed glottis (Adapted from source).

The Valsalva maneuver often occurs naturally before typical performance requiring core support and high power output. For example, imagine you are trying to push your broken-down car to the repair shop. You will likely (even unconsciously) take in a lot of oxygen and perform the Valsalva maneuver by holding your breath before you start pushing. In practice, people intuitively use the Valsalva maneuver to some extent when the load is around 80% of their maximum (4). This is likely the body's natural reaction to protect the spine from injury (5). In strength training, just the unconscious Valsalva maneuver often isn't sufficient, and maximizing support also requires diaphragmatic breathing and core engagement in conjunction with it. This can significantly increase power output (6).
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Figure 5: Eco-friendly commuting. This certainly involves the Valsalva maneuver. (Source)

Instructions for the Valsalva Manoeuver: Take a deep breath (diaphragmatic breathing). Try to follow this with a strong exhalation, but do not allow air to come out. Although this might sound like a challenging thing to do, it is actually quite simple and natural. A good mental image is to hold your breath as if preparing to take a punch to the midsection. This breath-holding and the Valsalva maneuver are actually done simultaneously with core engagement, which we will discuss further next.

Engaging the core

Simply taking in oxygen and performing the Valsalva maneuver are not sufficient; you must also tighten your core as much as possible in conjunction with them. Sometimes, you may hear advice to "suck in your stomach." This is incorrect advice in the context of strength training. As an example, here is an illustration of how not to do it:

Figure 6. An example of how not to tighten the torso during a repetition (source adapted).

In core engagement related to strength training, the core musculature, especially the abdominal and lower back muscles, contract statically. The core muscles function as a framework against which the pressure in the abdominal cavity increases through diaphragmatic breathing and the Valsalva maneuver. In addition to increasing pressure, the core musculature also contracts, thereby tightening the entire core and maintaining the spine in a stable position, facilitating efficient force transmission throughout the core. The static contraction of the lower back muscles, in particular, is crucial to keeping the spine as tight and straight as possible. This may require more precise learning, especially for beginners (an example of learning to contract the lower back muscles can be found in this video).

The role of the abdominal muscles is important in increasing the pressure within the abdominal cavity (7), However, mechanically speaking, the abdominal muscles do not work significantly in large movements such as squats and deadlifts. This may be somewhat surprising, so here's a more detailed explanation: Abdominal muscles primarily function as spinal flexors (spinal flexion rounds the spine, as in a sit-up, for example). In exercises like squats, we don't want the spine to round. Instead, in large multi-joint movements, the mechanical load is primarily placed on our lower back muscles. This has been observed in several studies. The activation of abdominal muscles is quite low, for example in squats, compared to typical abdominal exercises (8). The strength of the abdominal muscles also does not appear to correlate with squat performance (9).

So, the strength of the abdominal muscles likely does not limit your performance in large movements because they do not work anywhere near maximally during the exercises. Therefore, core tightness primarily depends on the strength of the lower back muscles and the ability to create internal pressure in the abdominal cavity, rather than the strength of the abdominal muscles. Experienced trainees are capable of generating more internal pressure in the abdominal cavity, and stronger abdominal muscles do help increase this pressure (10).
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Figure 7:  The collaboration of the Valsalva maneuver, lower back muscles, and abdominal muscles in supporting the core during the back squat (glottis = vocal cords). Picture taken from Starting Strength: Basic Barbell Training 3rd edition. 2013. Used with permission of the author.
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The goal is to have your entire core as tight as possible and your spine as supported as possible. In fact, the entire body should be as tight as possible. This is also somewhat movement-specific; in addition to focusing on core tightness, there are other areas to consider, depending on the exercise. For example, in squats, you should also focus on upper back tightness, while in the overhead press, you should pay attention to the tightness of your legs. However, the core is the most critical area that must be kept tight in every exercise.
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Insructions for core engagement: After diaphragmatic breathing, imagine preparing to take a blow to the abdomen and contract all the muscles in the entire core area as much as possible. This way, you simultaneously perform the Valsalva maneuver and tighten the core. Contract the entire core area statically, including the rectus and oblique abdominal muscles, as well as the lower back muscles. It's a good idea to practice this step with a belt because it increases the pressure within the abdominal cavity, and you can feel it more clearly against the belt. Your core should feel extremely tight and stable compared to the normal state. Additionally, you can push your chest slightly downward (without rounding the spine) during the Valsalva, which will cause the internal pressure to increase as the internal intercostal and abdominal muscles compress the abdominal cavity further, providing more core support for the lift. You can see an example performance in the video below.
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Video. Here is an example of an excellent breathing technique during a squat. For example, you can see the diaphragmatic breathing particularly well in the video.

Briefly, about using a belt

‍The use of a belt is often misunderstood. Its purpose is not to keep the back and core passively tight but to increase the internal pressure in the abdominal cavity – pressure increases as the abdominal cavity expands against the belt. Proper belt use can increase the internal pressure in the abdominal cavity, for example, in squats, by up to 30-40% compared to squats without a belt (11). This supports our midsection and is the correct way to use a belt.
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How much oxygen should I take before a repetition?

This is quite individual – some people fill their lungs as full as they can, while others leave the lungs a bit short. In studies by Professor Stuart McGill, who specializes in breathing and spinal loading, maximum intra-abdominal pressure was achieved when inhaling to 70% of vital capacity (from Vranich, B. 2019).

You can find the right amount of air for yourself by experimenting with when you feel the position is truly strong and tight. Coaches often recommend taking in as much air as possible, which is a good starting point because many people have the issue of not taking in enough air. So, by experimenting, you can find your optimal air intake. We generally recommend taking in almost maximum air, especially before heavy repetitions.

The Valsalva method and health risks?

Some individuals may be concerned that the increase in blood pressure resulting from lifting weights and using the Valsalva maneuver may expose them to cardiovascular issues or strokes. However, there is little evidence to support this, and such cases seem to be extremely rare in the context of strength training (12).

Dr. Jonathon Sullivan, a physician and medical doctor, has written a comprehensive review of the risks and safety of the Valsalva maneuver when lifting weights. You can read it here.

‍Based on Sullivan's article, it appears that using the Valsalva maneuver in strength training does not increase the risk of heart attacks or aneurysms in healthy individuals. You can also read about this topic in Dr. Austin Baraki's article here.

‍NOTE!  If you have any cardiovascular disease or circulatory system condition, it is advisable to consult a doctor before using the Valsalva maneuver.

Summary

As noted, proper breathing technique is an essential aspect of strength training. Correct breathing technique enables efficient and safe training and serves as the foundation for the technique of practically all major movements. Learning the right breathing technique doesn't take much time, but it undoubtedly adds more weight to the bar and makes lifting much more stable, comfortable, and effective in terms of training impact.
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- M.Sc Exercise Physiology,
Tapio Tulenheimo & Julius Granlund

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