Aging Spine Fitness: Evidence-Based Strengthening Techniques for Seniors: Summary 12
the lesser trochanter of the femur. It is a powerful hip flexor that, when tight, causes axial compression through the spine and forces the spine into lumbar lordosis. Research indicates a person must stand 3–4 hours per day to avoid iliopsoas contracture. Most older adults fall far short of this. The rectus femoris, part of the quadriceps, has a pelvic attachment and, when tight, pulls the pelvis into anterior rotation, further increasing lumbar lordosis. Both muscles tend toward tightness and must be regularly stretched. Muscle Imbalance Pattern in Older Adults Because of sedentary lifestyles and the aging process, older adults predictably develop the following muscle imbalance pattern: • T ight : Hip flexors (iliopsoas, rectus femoris), erector spinae, anterior chest • Weak : Gluteus maximus, gluteus medius, transversus abdominis/abdominals, multifidus The treatment approach follows directly from this pattern: Stretch the iliopsoas, stretch the rectus femoris, strengthen the multifidus, strengthen the abdominals, strengthen the gluteus maximus, and strengthen the gluteus medius. SPINAL STRUCTURES AND AGE-RELATED CHANGES Intervertebral Disc The intervertebral disc is a largely avascular structure composed of three components: The nucleus pulposus (gel-like center, 66–88% water), the annulus fibrosus (concentric circles of collagen with alternating fiber orientations for strength), and two vertebral endplates (which cover the superior and inferior aspects of the disc, binding it to the vertebral body and allowing nutrient diffusion). The disc acts as a shock absorber and provides flexibility and stability to the spine. Age-Related Changes to the Nucleus Pulposus The aging nucleus pulposus undergoes the following changes: • Loss of hydration: Loses water, resulting in decreased cushioning ability. • Increased stiffness: Loss of water and changes in the extracellular matrix (ECM) decrease shock absorption ability. • Reduced disc height: Because of loss of water and ECM changes Disc degeneration is seen in 80% of asymptomatic older adults. The aging annulus fibrosus also undergoes decrease in water content and proteoglycans, collagen degradation, delamination of layers, and development of cracks and fissures. The vertebral endplates thin because of decreased bone mineral density, undergo ossification (impeding nutrient flow), and become more concave.
LEARNING TIP! Transversus Abdominis (TA)
The transversus abdominis (TA) is the deepest abdominal muscle. Its fibers run horizontally, wrapping around the trunk from front to back. It segmentally stabilizes the spine, preventing excess motion and twisting. The TA works in synchrony with the multifidus. Together, they are the primary segmental stabilizers of the spine. It also maintains abdominal tension and supports lumbopelvic motion. Obliques (External and Internal) The external obliques are the most superficial abdominal muscles, functioning in trunk flexion, rotation to the opposite side, lateral flexion, and increasing abdominal pressure. The internal obliques lie between the external obliques and the TA, running perpendicular to the external obliques. They function in sidebend and rotation (unilateral), forced exhalation, and pelvic stabilization. Because the obliques run diagonally, exercises must include a diagonal stress component to adequately strengthen them. Hip Muscles with Spinal Influence Gluteus Maximus The gluteus maximus originates from the posterior ilium, sacrotuberous ligament, dorsal sacrum, lateral coccyx, and gluteal aponeurosis, inserting into the gluteal tuberosity of the femur and iliotibial band. It extends and externally rotates the hip, controls pelvic motion, and influences lumbar spine movement and stability through pelvic control. It is part of the posterior oblique system, linking the gluteus maximus on one side with the latissimus dorsi on the other side via the thoracolumbar fascia, contributing to core stability during reciprocal activities like walking and running. The gluteus maximus tends toward weakness in older adults. Gluteus Medius The gluteus medius runs from the gluteal surface of the ilium to the lateral surface of the greater trochanter. While commonly described as a hip abductor, its primary functional role is as a lateral pelvic stabilizer during single-leg stance and gait. It works with the contralateral QL to keep the pelvis level. Weakness is evidenced by a hip drop (Trendelenburg sign) or compensatory trunk sidebend during gait. The gluteus medius tends toward weakness in older adults and is a key exercise target. When the pelvis drops, the lumbar spine side bends making gluteus medius stability critical for spinal health. Hip Flexors (Iliopsoas and Rectus Femoris) The iliopsoas (fusion of iliacus and psoas) originates from the transverse processes of L1–L5, anterior vertebral bodies of T12–L5, and intervertebral discs, inserting into
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