The squat is a foundational movement in strength training, engaging large muscle groups in the lower body, including the quadriceps, hamstrings, and glutes. Proper breathing is directly linked to spinal stability and the capacity to generate force during the lift, not just oxygen flow. Specialized breathing techniques transform the core into a rigid cylinder, which is necessary for protecting the spine under load and ultimately determining how much weight can be lifted safely.
Foundational Breathing The Exhale on Exertion Rule
For warm-up sets, lighter loads, or higher repetition ranges, a continuous and rhythmic breathing pattern is the recommended approach. This technique, often called the “exhale on exertion rule,” ensures a steady supply of oxygen and helps maintain a manageable level of intra-abdominal pressure.
The pattern dictates that the lifter should inhale deeply just before or as they begin the eccentric phase (the lowering motion of the squat). This inhalation should be a deep, diaphragmatic breath that expands the abdomen and lower ribs, rather than a shallow breath that only lifts the chest.
As the lifter begins the concentric phase (the upward drive out of the bottom of the squat), they should exhale forcefully through the mouth. This strong exhalation coincides with the maximal effort portion of the lift. The timing of the exhale helps engage the deep core muscles, providing trunk stability without the high pressures associated with breath-holding. This consistent inhale-exhale rhythm prevents excessive pressure buildup and is the safest, most sustainable method for beginners or those training for muscle endurance.
The Crucial Role of Bracing and Intra-Abdominal Pressure
While continuous breathing works well for sub-maximal weights, effective spinal support under heavier loads requires a deliberate bracing technique that generates Intra-Abdominal Pressure (IAP). IAP is the pressure created within the abdominal cavity when the diaphragm contracts and pushes downward against the abdominal organs, while the core muscles simultaneously resist this force. This mechanism acts as the body’s internal weightlifting belt, stiffening the entire torso.
The proper technique involves a “360-degree brace,” achieved by consciously breathing into the sides and back, not just the front of the abdomen. The diaphragm contracts and compresses the abdominal contents, causing the abdominal wall, pelvic floor, and posterior stabilizers to activate eccentrically in response. This creates a pressurized “fluid ball” that supports the vertebral column from within.
Generating sufficient IAP is foundational for safely handling heavy weights because it significantly reduces the compressive and shearing forces placed on the lumbar spine. Studies suggest that increased IAP can reduce spinal compressive loads by up to 40% during a lift. This internal stabilization allows the body to transfer force more efficiently from the legs through a rigid core, enabling the primary moving muscles to work harder and more effectively. The brace is maximized when the entire trunk is expanded outward, not when the abdominal muscles are simply “sucked in” or contracted.
Advanced Technique Utilizing the Valsalva Maneuver
For maximal-effort lifts, such as a one-repetition maximum or any weight exceeding approximately 80% of capability, the Valsalva Maneuver is employed to maximize IAP and spinal rigidity. This technique involves taking a large, deep diaphragmatic breath and then holding that air by closing the glottis (the part of the larynx that contains the vocal cords). The lifter performs the entire descent and ascent of the squat while breathing out against this closed throat, trying to exhale without letting any air escape.
Holding the breath throughout the movement creates the highest possible level of Intra-Abdominal Pressure, providing unparalleled torso stiffness necessary for supporting the heavy load. Once the repetition is complete and the lifter is standing tall, the breath is forcefully exhaled. This method is a powerful tool for strength, but it carries inherent physiological risks. The intense pressure buildup causes a temporary but significant spike in heart rate and blood pressure, which can momentarily rise three to four times above resting levels.
For this reason, the technique is not recommended for individuals with pre-existing cardiovascular conditions or high blood pressure. The breath hold should be kept brief, ideally no longer than three seconds, to mitigate the risk of dizziness or fainting. The Valsalva Maneuver is an advanced strategy to be used sparingly for heavy sets by experienced lifters who have already mastered the foundational bracing technique.