Intra-abdominal pressure (IAP) is a key physiological parameter for trunk stability and control of lumbar movement. Over recent decades, numerous studies have shown that ineffective management of this pressure can contribute to the onset or persistence not only of low back pain, but also of urogenital disorders, disc protrusions, and herniations.
IAP is the pressure generated within the abdominal cavity when the diaphragm contracts downward, while the pelvic floor and abdominal wall activate to contain it. Under optimal conditions, a stable pressure cylinder is created, formed by the diaphragm (superiorly), the pelvic floor (inferiorly), the abdominal wall (anteriorly and
laterally—particularly the transversus abdominis and internal oblique), and the lumbar multifidus muscles (posteriorly).
This system (Hodges et al., 1997, Spine)—on which Hypopressive Techniques are based— acts as a functional unit that stabilizes the lumbar spine during movement and load transmission.
Intra-abdominal pressure functions like a hydraulic shock absorber, supporting the spine from within. When maintained within physiological values, IAP reduces direct compression on the intervertebral discs, improves load distribution across the vertebrae, increases trunk stiffness (functional rigidity), and decreases compensatory overactivity of the superficial paraspinal muscles.
An increase in intra-abdominal pressure occurs when pressure inside the abdominal cavity rises beyond physiological levels due to a reduction in cavity volume and an imbalance between containment forces (core muscles, diaphragm, and pelvic floor) and pressure-generating forces (breathing, physical effort, external loads).
Main causes
1. Intense or poorly managed physical effort
One of the primary causes is lifting heavy loads without adequate respiratory control, forced exhalation with a closed glottis (Valsalva maneuver), and demanding training sessions performed without sufficient ability to control and activate the abdominal wall (e.g., squats, deadlifts, push-ups), often executed while holding the breath.
2. Inefficient breathing
This may be due to predominant upper chest breathing, a poorly mobile or overly tense diaphragm, and lack of synergistic activation between the diaphragm, pelvic floor, and abdominal wall.
The result is increased downward pressure on the pelvic floor and antero-posterior pressure on the intervertebral discs.
3. Core weakness or dysfunction
Poor activation of the transversus abdominis leads to reduced abdominal containment, lumbar instability, and loss of pressure control.
4. Postural alterations
Lumbar hyperlordosis or thoracic rigidity, along with positions that compress the abdominal cavity (prolonged sitting, kyphotic posture), significantly contribute to increased IAP, as do postural deviations and structural alterations such as scoliosis.
5. Clinical or physiological conditions
Although often temporary, conditions such as pregnancy and postpartum, constipation, persistent coughing, abdominal overweight, scoliosis, and pelvic floor dysfunctions can also cause a significant increase in IAP.
Why managing IAP is important
Chronic elevation of IAP can:
1. Increase pressure on intervertebral discs, promoting low back pain, disc protrusions, and herniations;
2. Progressively weaken the pelvic floor, leading to incontinence and prolapse;
3. Impair abdominal venous and lymphatic return;
4. Contribute to abdominal diastasis (not only during pregnancy);
5. Reduce respiratory efficiency and thoracic mobility.
Conversely, excessively low IAP leads to lumbar instability and muscular overload.
Therefore, intra-abdominal pressure itself is not harmful—it is a fundamental mechanism for spinal stability and protection. It becomes problematic only when managed in a dysfunctional way.
The role of breathing
Breathing is the primary modulator of IAP. During diaphragmatic inhalation, pressure increases; during exhalation, it decreases. A correct breathing pattern—coordinated with movement and core activation—is therefore essential to maintain stability without creating excessive abdominal pressure.
Proper management of intra-abdominal pressure means protecting the spine and reducing low back pain, as well as lowering the risk of disc protrusions, herniations, diastasis, prolapse, and incontinence.
Beyond general advice—such as breathing correctly in relation to movement, strengthening the core, and avoiding breath-holding during effort—consider practicing Hypopressive Techniques, which reduce abdominal pressure, activate the pelvic floor, and improve spinal stability.