Low Back Tidbits

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The spinal column consists of 33 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused), and 4 coccygeal (fused).


Injury occurs when the spine and its supporting structures cannot withstand acute or chronic forces (ie compression, distraction, shear).


The curvature of the spine is preserved in part by the ligamentum flavum, which runs between the posterior aspects of the vertebral bodies. The paraspinous musculature, which runs anterior to the spine, works to counterbalance the body's center of gravity. Normally, the anterior aspects of the spine bears most of the body's load in an upright position.


In 2006, Over 27% of adults (18 years of age and over) had low back pain in the past 3 months. Over 14% had recent neck pain.

U.S. Dept of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics, Health, United States, 2007.


75% of elite athletes have complained of back pain at some point in their careers.

Spencer CW III, Jackson DW. Back injuries in the athlete. Clin Sports Med. 1983; 2: 191-215.

Gerbino PG II, Micheli LJ. Back injuries in the young athlete. Sport Med Arthroscopy Rev. 1996; 4 : 122-131.


The incidence of symptomatic thoracic intervertebral disc herniation is rare in comparison to herniations of the lumbar or cervical areas of the spine. Of those cases occurring in thoracic region, more than 75 percent of disk herniations occur below T8. The peak is at T11-12 where there is greater spinal mobility. Central protrusions are the most common.

Okada Y, Shimizu K, Ido K, Kotani S (1997) Multiple thoracic disc herniations: case report and review of the literature. Spinal Cord, 35: 182-186.


According to McGill. relatively few low back injuries occur from a single event. He proposes a back injury most often occurs after a series of excessive loads gradually and progressively reduced tolerance to tissue failure. He further explains the injury process may not always be associated with loads of high magnitude.

ACSM (2001), ACSM's Resource Manual for Guidelines for Exercise Testing and Prescription, 4th ed, pg 117.


LBP Prognosis

Acute low-back pain (lasting less than 3 weeks) usually resolves itself without any intervention

    • 75% of individuals recover from acute low back pain within 3 weeks
    • 90% of individuals recover from low back pain within 2 months

Chronic low-back pain (symptoms lasting more than 7 weeks)

    • number one cause of disability in the United States
    • the longer an individual suffers from CLBP, the worse the prognosis

Carpenter DM, Nelson BW (1999). Low back strengthening for the prevention and treatment of low back pain. Medicine and Science in Sports and Exercise Jan; 31(1): 18-24 .


Low Back Debate

McGill condemns the use of isolated lumbar spine machines claiming the compressive forces of these devices can cause disc herniation based on a pig spine model. Nelson recommends the use of these devices and has successfully used these devices to treat chronic low back pain. See Erector Spinae Weakness. McGill suggests certain exercises and movements that flex the spine through the full range of motion be should be eliminated, although he admits several thousands of cycles under a load to full range of motion are required to produce disk herniations. It can be argued that potential injury would be prevalent in this situation not due to full range of motion, but rather due to overtraining or lack of progressive adaptation. Nelson explains the avoidance of full range of motion during exercise is a short term solution which promotes deconditioning and consequently, deterioration of the joint structures. Eric Serrano, MD, (ExRx.net medical advisor) suggests these machines can be useful in the early stages of rehabilitation. Dr. Serrano prescribes more functional movements as the patient progresses, introducing transverse / multiple plane exercises in the later stages, particularly with athletes. Also see adaptation criteria and Dr. Nelson's audio interview.

McGill Stuart (2002), Low Back Disorders, pg 55. Textbook

Nelson, B.W., O'Reilly, E., Miller, M., Hogan, M. Wegner, J.A., Kelly, C., (1995). The clinical effects of intensive, specific exercise on chronic low back pain: a controlled study of 895 consecutive patients with 1-year follow up. Orthopedics, 18(10), 971-981.

Nelson, B.W. (1993). A rational approach to the treatment of low back pain. J Musculoskel Med, 10(5), 67-82.


Sitting and Occupational Low Back Pain

Sitting by itself does not seem to increase the risk of low back pain or sciatica. The risk, however, increases while sitting in awkward postures, sitting for more than half of the workday, and during whole body vibrations, such as in certain vehicles and on machinery.

Eur Spine J. (2006). Association between sitting and occupational LBP.


Walking & Low Back Health

Walking may benefit low back health by imposing a rotational torque on the spine at an estimated 8° of rotation. The vertebral disk undergoes this torque along with a slight degree of compressive force from the upper body weight and contraction of the trunk muscles. The torque is impressed on the annular fibers of the intervertebral disks enhancing their rigidity.

Cailliet M (1996). Low back Pain. Soft Tissue Pain and Disability, FA Davis Company Philadelphia. 3; 153-155.


Training Frequency

Training once per week may be just as effective as training two or three sessions per week when measuring isolated lumbar strength.

Graves JE, Pollock ML, Foster D, Leggett SH, Carpenter DM, Vuoso R, Jones A (1990). Effect of training frequency and specificity on isometric lumbar extension strength. Spine;15(6):504-9.


Spondylolysis & Spondylolisthesis

  • Definition
    • Spondylo: spine
    • Lysis: dissolution
    • Listhesis: slipping or falling
  • Classifications
    • Type I (isthmic)
      • Anatomic defect in pars interarticularis.
      • Usually found in adolescents and may be a result of trauma causing a fatigue fracture.
      • The fracture usually heals and becomes stable.
    • Type II (congenital)
      • Postural elements are structurally inadequate due to developmental defects.
    • Type III (degenerative)
      • Facits and their ligamentous supporting structures have become deficient.
    • Type IV (elongated pedicles)
      • Variation of isthmic: neural arch is elongated positioning the facets more posteriorly.
    • Type V (destructive disease)
      • Any systemic bone pathology caused by metabolic, metastatic, or infectious disease


Spinal Stenosis

Condition involving any type of narrowing of the spinal canal, nerve root canals, or tunnels of intervertebral foramina. First described by Verbiest in 1954.


Piriformis syndrome

Entrapment of the sciatic nerve as it emerges from under the piriformis muscle may cause low back pain with sciatic radiation. Sciatica is usually caused by pressure on a dorsal root and/or a ventral root. Sciatica can also result from pressure on the sciatic nerve in the pelvis, gluteal region, or thigh.

The sciatic nerve is really two nerves, the tibial and common peroneal nerves. In most cases the sciatic nerve passes inferior to the piriformis muscle. In 10 to 12% of the population, the sciatic divides before entering the gluteal region and the common peroneal division passes through the piriformis. In 0.5% of the population the common peroneal division passes superior to the piriformis.

Moore KL (1985). Clinically Oriented Anatomy, Williams & Wilkins, 2.

Cailliet M (1996). Low back Pain. Soft Tissue Pain and Disability, FA Davis Company Philadelphia. 3; 153-155.


Scoliosis

Adam's TestMediolateral curve of the vertebral column.

  • Structural scoliosis
    • caused by deformity in vertebrae
  • Functional
    • caused by mechanical problem
      • examples: one short leg, muscle spasm on one side
    • disappears with forward flexion of trunk as the back becomes horizontal
    • can be treated with bracing, heel lift, or exercise
      • exercises
        • stretch concave side curve
        • strengthen convex side of curve
      • if vertebral column rotation present
        • appropriate oblique abdominal strengthening
  • Screening
    • Adam's Test
      • Viewing subject spine while standing may not reveal scoliotic curves
      • Bending forward at waist allows for easier detection
  • Refer to physician if:
    • Structural scoliosis
    • Functional scoliosis
      • deviations greater than 20 degrees
      • vertebral column rotation detected
    • Therapy in these cases are not within realm of exercise professional

Kreighbaum, E., Barthels, K.M., (1996). Biomechanics; A Qualitative Approach for Studying Human Movement, Allyn & Bacon, 4, 235.


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