Roberts Physical Therapy & Massage

02/24/2026

Breathing is not only a respiratory function but also a fundamental biomechanical process that supports spinal stability and postural control. The diaphragm, abdominal wall, pelvic floor, and deep spinal stabilizers work together to create a pressure-regulating system that stabilizes the trunk. The illustration highlights how diaphragmatic breathing distributes pressure evenly throughout the abdominal cavity, forming a supportive internal cylinder.

During proper inhalation, the diaphragm contracts and descends, increasing intra-abdominal pressure. Instead of the abdomen pushing forward only, pressure expands in all directions — anteriorly, laterally, and posteriorly — creating 360-degree expansion. The pelvic floor responds by lengthening slightly, while the transverse abdominis and oblique muscles regulate the expansion. This balanced pressure supports the lumbar spine and reduces excessive reliance on passive structures like ligaments and discs.

From a biomechanical standpoint, intra-abdominal pressure functions like an internal brace for the spine. When pressure is evenly distributed, it enhances trunk stiffness and stability without excessive muscular tension. This mechanism is crucial during lifting, walking, and athletic movements, as it improves force transfer between the upper and lower body while minimizing spinal strain.

The side-view illustration shows how pressure interacts with spinal alignment. With efficient diaphragmatic breathing, pressure supports the lumbar curve and maintains trunk integrity. In contrast, shallow chest breathing elevates the rib cage, limits diaphragm descent, and shifts stabilization demand to the neck, shoulders, and lower back. Over time, this inefficient pattern may contribute to neck tension, lumbar pain, and reduced core stability.

Poor pressure management can also overload the pelvic floor. If pressure is directed downward without coordinated muscular support, it may contribute to pelvic floor dysfunction. Conversely, excessive abdominal gripping without diaphragm coordination can increase spinal compression and restrict breathing efficiency.

Restoring optimal breathing mechanics involves retraining diaphragmatic function, improving rib cage mobility, and strengthening deep core musculature. When the diaphragm, abdominal wall, and pelvic floor coordinate effectively, the body gains a stable foundation for posture, movement, and injury prevention.

Efficient breathing creates a stable yet adaptable trunk, enhances movement efficiency, and supports long-term spinal health — demonstrating that proper respiration is essential not only for oxygen exchange but also for biomechanical integrity.

02/24/2026

02/24/2026

LOWER CROSSED SYNDROME

This image represents Lower Crossed Syndrome, a classic postural and biomechanical imbalance pattern described in the lumbopelvic region. Biomechanically, it is characterized by an anterior pelvic tilt caused by an imbalance between tonic (overactive) and phasic (underactive) muscle groups acting on the pelvis and lumbar spine.

In this pattern, the hip flexors (iliopsoas, re**us femoris) and lumbar extensors (erector spinae) become adaptively tight and overactive. Their constant pull rotates the pelvis anteriorly, increasing lumbar lordosis. This alters the neutral alignment of the spine and shifts load-bearing stress to the posterior elements of the lumbar vertebrae, including facet joints and posterior annulus of the intervertebral discs.

Opposing these tight muscles are the abdominals (especially transverse abdominis and lower fibers of re**us abdominis) and the gluteal muscles, which become lengthened and weak. From a biomechanical standpoint, weak abdominals fail to counterbalance lumbar extension forces, while inhibited gluteus maximus reduces effective hip extension torque. As a result, movement that should occur at the hip is compensated by excessive motion in the lumbar spine.

During functional activities such as walking, running, squatting, or prolonged standing, this imbalance disrupts the lumbopelvic rhythm. Hip extension becomes lumbar extension-dominant, increasing shear forces at the L4–L5 and L5–S1 segments. Over time, this contributes to mechanical low back pain, facet irritation, disc stress, and reduced shock absorption during gait.

Posturally, the biomechanical chain effect is visible as a forward-shifted pelvis, protruding abdomen, and exaggerated lower-back curve. The altered center of mass increases muscular energy demand and reduces movement efficiency, explaining early fatigue and recurrent pain in individuals with prolonged sitting habits.

Lower Crossed Syndrome is not merely a muscle tightness issue but a load-distribution and motor-control problem. Restoring biomechanical balance requires reducing excessive lumbar extension forces while re-establishing efficient force transfer through the hips and core.

02/24/2026

The myodural bridge.

Sagittal section of the myodural bridge and its connections to the dura and spine. The posterior atlantooccipital membrane
(1) extends from the occiput and coalesces with the dura mater at the cerebrospinal junction. The superior myodural bridge

(2) merges with the superior vertebrodural ligament

(3) of the atlas and fuses with the PAOM at the level of the atlantooccipital interspace. The inferior myodural bridge comprised of the re**us capitis posterior major fascia

(5a) and obliquus capitis inferior fascia (5b) courses between the atlantoaxial ligamentum flavum

(4) as bundles of dense fibers. The inferior myodural bridge fuses with the PAOM. The nuchal bridge

(6) merges with the inferior vertebrodural bridge

(7) and attaches to the PAOM. The PAOM terminates at the level of C3 after this transition point (*).

The dura mater (DM) continues as an independent structure after that. O, occiput; C1, atlas; C2, axis; C3, third cervical vertebra; NL, nuchal ligament; PAOM, posterior atlantooccipital membrane.

02/24/2026

The diaphragm, abdominal wall, and pelvic floor function together as a pressure-regulating system that stabilizes the spine and supports efficient movement. The illustration contrasts two core pressure strategies: one showing balanced pressure distribution and the other demonstrating dysfunctional pressure patterns. Understanding this pressure system is essential for spinal health, breathing efficiency, and core stability.

In optimal function, the diaphragm contracts and descends during inhalation, increasing intra-abdominal pressure (IAP). This pressure expands outward in all directions — anteriorly, laterally, and posteriorly — while the pelvic floor responds eccentrically and the deep abdominal muscles (especially the transverse abdominis) regulate expansion. This coordinated expansion creates a pressurized cylinder that stabilizes the lumbar spine and reduces excessive load on passive structures such as discs and ligaments.

The abdominal wall plays a critical role in managing pressure. When functioning properly, it expands circumferentially rather than pushing forward excessively. Lateral rib expansion and posterior pressure distribution improve spinal support and enhance trunk stiffness without excessive muscular strain. This balanced pressure system improves force transfer between the upper and lower body during lifting, walking, and athletic activities.

In dysfunctional breathing or poor core control patterns, pressure is misdirected. Instead of expanding evenly, the abdomen may protrude forward while the rib cage elevates and flares. This pattern reduces diaphragm efficiency and increases reliance on accessory breathing muscles. The pelvic floor may experience excessive downward pressure, while the lumbar spine loses its pressure-supported stability, increasing risk of lower back pain and pelvic dysfunction.

Excessive abdominal gripping or improper bracing can also disrupt pressure regulation. When muscles contract rigidly without coordinated diaphragm movement, breathing becomes shallow and intra-abdominal pressure becomes poorly distributed. This can increase spinal compression rather than providing supportive stabilization.

Efficient core biomechanics rely on coordinated diaphragm descent, controlled abdominal expansion, pelvic floor responsiveness, and spinal alignment. Training diaphragmatic breathing, improving rib cage mobility, and strengthening deep core musculature help restore pressure balance and spinal stability.

When the pressure cylinder functions optimally, the spine is supported, breathing becomes efficient, and movement becomes more powerful and controlled. This integrated system forms the foundation for posture, injury prevention, and functional strength.

02/24/2026

02/24/2026

02/24/2026

SPINAL EXTENSION & ANTERIOR PELVIC TILT

This image illustrates the biomechanics of excessive spinal extension combined with anterior pelvic tilt, a posture commonly seen in prolonged standing, faulty exercise technique, or postural imbalance. Biomechanically, the pelvis rotates anteriorly while the lumbar spine increases its lordotic curvature, shifting the trunk backward relative to the hips. This alters the natural load-sharing mechanism between the spine, pelvis, and lower limbs.

At the lumbar spine, increased extension causes posterior approximation of the facet joints. As the lumbar vertebrae tilt backward, compressive forces rise at the facet joints while tensile stress increases on the anterior longitudinal structures. Over time, this excessive posterior loading can irritate facet joints, reduce intervertebral disc shock absorption, and contribute to extension-related low back pain.

The rib cage and thoracolumbar junction also play a critical role. With excessive extension, the rib cage flares upward and forward, reducing abdominal wall contribution to spinal stability. This rib flare shifts the center of mass posteriorly, forcing the lumbar extensors to remain constantly active to prevent collapse, thereby increasing muscular fatigue and passive tissue stress.

From a pelvic biomechanics perspective, anterior pelvic tilt lengthens and weakens the abdominal muscles while placing the hip flexors in a shortened, dominant position. Simultaneously, the gluteus maximus becomes biomechanically disadvantaged, reducing its ability to counteract pelvic tilt during standing and movement. This imbalance reinforces the extension posture and increases shear forces across the lumbosacral junction.

During functional movements, such as overhead reaching or lifting, this posture magnifies spinal loading. Instead of distributing motion across the hips and thoracic spine, movement becomes concentrated in the lumbar region. The arrows in the image represent these abnormal force vectors, highlighting increased compressive forces from above and shear forces at the lumbopelvic interface.

In summary, this biomechanical pattern represents a loss of neutral spine control, where excessive lumbar extension and anterior pelvic tilt disrupt efficient force transfer. Restoring balanced rib–pelvis alignment, improving abdominal control, and re-establishing hip-driven movement are essential to reduce spinal stress and improve postural efficiency.

02/23/2026