 Because of the reduced postural stability of these individuals, prolonged sitting may cause them to adopt a flexed spinal posture and posteriorly tilted pelvis.Because these individuals may be unable to physically reposition without considerable assistance, their bodies can be subject to considerable positional strain and immobility, with detrimental physical repercussions.Adverse health effects include the formation of pressure ulcers, low back pain, and lumbar immobility and joint stiffness.