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Aging Spine Fitness: Evidence-Based Strengthening Techniques for Seniors: Summary 11
The disc provides spacing that allows the joint to function optimally. During flexion and extension, motion occurs at the two facet joints, which in turn affects the disc. The disc compresses in different areas as the spine moves through its range of motion. Segmental motion at each level contributes to gross trunk motion. IMPORTANT MUSCLES FOR SPINE MOTION AND STABILITY Posterior Muscles Erector Spinae The erector spinae is a large, superficial group of three muscles: Iliocostalis (most lateral), longissimus (intermediate), and spinalis (most medial). Their primary functions include bilateral back extension, controlling descent during forward trunk bending, and unilateral sidebend/rotation. Importantly, the erector spinae may become hypertonic when the multifidus is weak or atrophied. A tight, painful erector spinae is often a sign of underlying multifidus weakness, not a simple muscle strain. Because the erector spinae spans multiple levels, tightness increases axial compression through the spine and creates an extension moment. Quadratus Lumborum (QL) The QL is the deepest back muscle, running from the iliac crest to the transverse processes of L1–L5 and the 12th rib. Its primary functions are fixing the 12th rib to stabilize the diaphragm during inspiration and working with the contralateral gluteus medius to maintain frontal plane stability of the pelvis. In single-leg stance, the QL on one side and the gluteus medius on the opposite side work together to keep the pelvis level. Multifidus The multifidus spans the length of the spine but is most prominent in the lumbar spine. It runs lateral (transverse process) to medial (spinous process), spanning 2–5 vertebral segments. Although sometimes called a deep rotator, its primary function is segmental stability of the spine. Research has shown that when there is spinal dysfunction or pain, the multifidus will preferentially weaken, similar to how the quadriceps atrophy with knee pain or the gluteus maximus atrophies with sacroiliac pain. Multifidus weakness also contributes to erector spinae hypertonicity. Strengthening the multifidus should be a goal with every back pain patient. Anterior (Abdominal) Muscles Rectus Abdominis The rectus abdominis (the ”six-pack” muscle) runs vertically from the pubic crest to the xiphoid process and costal cartilage of ribs 5–7. It functions to flex the trunk, approximate the rib cage to the pelvis, assist in forced exhalation, and provide core stability and posture.
INTRODUCTION
Back pain is extremely prevalent among older adults, with estimates ranging from 21–75% of adults over 60 years of age. The prevalence increases with age and affects women more than men. Back pain is associated with significant functional disability that can limit a person's independence. Clinical Reasoning Framework for Prescribing Spine Exercises • Diagnosis : Often based on imaging that may not correlate well with patient symptoms. Even asymptomatic individuals can have significant structural changes on imaging. • Posture : Reveals how the spine is functioning and whether deviations are flexible or rigid. • Segmental mobility : Assesses how individual spinal segments are moving. • Muscle influences : Identify what is tight and what is weak. THE NORMAL SPINE The S-Curve A normal spine has a lordosis in the cervical and lumbar areas and a kyphosis in the thoracic area, creating an S-curve. This S-curve is optimal for shock absorption, segmental mobility and stability, and muscle function. As people age, they may develop an accentuated lordosis, accentuated kyphosis, or a flat back; all of which affect how the spine functions. Relative Motion in the Thoracic and Lumbar Region Different regions of the spine specialize in different movements. Flexion and extension are primarily functions of the lumbar spine and lower thoracic spine. Lateral side bending is distributed more evenly throughout the spine. Rotation is predominantly a thoracic spine function— most rotation occurs through the thoracic spine. This is clinically important when prescribing exercises: To mobilize lumbar segments, use flexion/extension rather than rotation. The Three-Joint Complex
LEARNING TIP! The spine is a three-joint complex: The
intervertebral disc and two facet joints function together to provide physiological spinal motion.
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