Final answer:
Factors that can lead to decompensation of ideal posture include bad posture, lifting heavy objects with the back, and certain medical conditions such as scoliosis or kyphosis.
Step-by-step explanation:
Factors that can lead to decompensation of ideal posture include bad posture, lifting heavy objects with the back, and certain medical conditions such as scoliosis or kyphosis. Bad posture, as shown in Figure 9.26, can create a clockwise torque around the hips that requires the back muscles to exert large forces to counteract it. Lifting objects with the back can cause muscle strain and damage to the discs and vertebrae due to the abnormally large forces created in the back muscles and spine. Medical conditions like scoliosis and kyphosis can result in abnormal or excessive curvatures of the spine, which can lead to decompensation of ideal posture.