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Back injury


Back injuries result from damage, wear, or trauma to the bones, muscles, or other tissues of the back. Common back injuries include sprains and strains, herniated disks, and fractured vertebrae. The lumbar is often the site of back pain. The area is susceptible because of its flexibility and the amount of body weight it regularly bears. It is estimated that low-back pain may affect as much as 80 to 90 percent of the general population in the United States.

Low-back pain is often the result of incorrect lifting methods and posture. Repetitive lifting, bending, and twisting motions of the torso affect both the degree of severity and frequency of low-back pain. In addition, low-back pain may also be the result of bad lifting habits. Sedentary lifestyles most often lead to weak abdominal muscles and hamstrings. This causes the stronger muscles which have remained strong to pull the body away from its optimal anatomical form. The imbalanced muscles cause people to continue to perform these repetitive actions. This results in misplaced force application within the spine, often resulting in hemorrhage of disks within the spinal column.

The muscles associated with the low back are known as the erector spinae muscle group. The actions that this muscle group cause include: sitting and standing with erect good posture, straightening the back or extending the back, arching the back, unilateral (side to side) flexion of waist, and rotation f the head in the highest aspect of this muscle group. The origins for the erector spinae muscle group are the nuchal ligament at the base of the back of the skull, ribs 3-12, thoracic and lumbar vertebrae, the thoracolumbar fascia, and the median and lateral sacral crests. The insertion is at each rib, cervical and thoracic vertebrae, and all the way up to the mastoid process.

The mechanism of injury to the low back during lifting is due to the length tension-relationship associated with muscle contraction, which means that when a muscle is fully contracted or shortened and when it is fully extended or relaxed it has the least force associated with contraction due to the least overlapping contractile molecules within the muscle fibers. When an individual is fully bent over the erector spinae muscle group is fully extended thus produces little force. Since there is little force available the gluteus maximus and hamstring muscles are initiate the standing motion when lifting objects from low places. Too rapid of back extension, or standing to an erect posture or standing with too heavy of a load can strain the erector spinae when it is at its weakest force output. This can lead to painful muscle spasms, tear tendons and ligaments in the back, and even rupture intervertebral disks (known as a herniated disk). Overall, it should be understood that the lumbar region of the erector spinae muscle group is not intended for lifting heavy weight, their main purpose is maintain proper posture. It is important to always crouch low to a load before lifting, and engage the strong extensor muscles of the lower limbs before standing erect with a load.


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