Low back injuries are very common in settings where frequent lifting occurs. Lifters experience small continual mechanical and neuromuscular perturbations because moving a load provides a constant disturbance to the lifter's balance and equilibrium (Gra-ham etal.,2011a; Oddsson etal.,1999).
When you lift a weight in wrong posture, it produces the effects of compressive stress, shear stress, and bending moment on the intervertebral disc, mostly between the fourth and fifth lumbar vertebrae.
But Most of the stress when lifting and bending is absorbed by the lower back. To take some pressure away from the spine, your abdominal and back muscles contract to give added support.
For example, when you lift a load, your abdomen and back muscles help
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The neck (cervical) and low back (lumbar) regions have a slight concave curve, and the thoracic and sacral regions have a gentle convex curve. The curves work like a coiled spring to absorb shock, maintain balance, and allow range of motion throughout the spinal column.
The muscles and correct posture maintain the natural spinal curves. Good posture involves training your body to stand, walk, sit, and lie so that the least amount of strain is placed on the spine during movement or weight-bearing activities.
The two main muscle groups that affect the spine are extensors and flexors. The extensor muscles enable us to stand up and lift objects. The flexor muscles include the abdominal muscles. These muscles enable us to flex, or bend forward, and are important in lifting and controlling the arch in the lower back. The back muscles stabilize your spine. Something as common as poor muscle tone or a large belly can pull your entire body out of alignment. Misalignment puts incredible strain on the spine
The main function of the lumbar spine is to bear the weight of the body. The five lumbar vertebrae are numbered L1 to L5. These vertebrae are much larger in size to absorb the stress of lifting and carrying heavy
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For example, high levels of lumbar flexion have been associated with increased ligamentous and lumbar disc loading, and elevated anterior shear forces (Adams and Dolan 1996, Arjmand et al 2011, McGill 1997, Potvin et al 1991). The lumbar posture adopted during lifting and lowering also influences the morphology, geometry and muscle activation levels of the erector spinae. A change in lumbar curvature can alter fascicle obliquity, lever arm distance, and the length-tension relationships of the erector spinae (McGill et al 2000, Raschke and Chaffin 1996, Singh et al 2011, Tveit et al 1994). These factors influence the ability of erector spinae to resist moments and exert forces (McGill et al 2000, Tveit et al