Strains and sprains are the leading cause of workplace injuries and illnesses, and the back and shoulders are the parts of the body most affected. Many of these injuries are part of a class of injuries known as “musculoskeletal disorders” or “MSDs.” This term is used in scientific literature to refer collectively to a group of injuries and illnesses that affect the musculoskeletal system; there is no single diagnosis for MSDs. MSD is an injury or disorder of the muscles, nerves, tendons, joints, cartilage, or spinal disks. They do not include disorders caused by slips, trips, falls, motor vehicle accidents, or similar accidents. Strains and sprains that result from repetitive motions are prevented or controlled through ergonomics. Ergonomics is the science of fitting working conditions to the people who have to do the work through the design of equipment and safety procedures.