Joints are designed to withstand pressure placed on them and provide full range of motion. A few examples of joints would be the ball-and-socket joints such as the hip; hinge joints such as the knee and elbow; and gliding joints, such as those located in the spine. To keep your joints in good shape it is important to have a healthy exercise regimen, proper nutrition, and a healthy lifestyle.
Joints are usually injured when an abnormal stress is placed on the joint. These stresses are placed by poor posture, poor joint position during a performance, or poor work ergonomics. To prevent repetitive stress injuries use these three basic principles: Lift heavy objects with the largest muscles, during activities assume several different positions, and keep joints in their neutral posture.