"We've seen a lot of masons with tendinitis and some with carpal tunnel syndrome," says Ju Me Wei, manager of The HealthSouth Center for Physical Therapy and Industrial Rehabilitation, located in Chicago. Back problems also are commonplace. Researchers are beginning to study the repetitive motion injuries suffered by masons, and are recommending preventive solutions. CUMULATIVE TRAUMA DISORDERS Cumulative trauma disorders (CTDs), also know as repetitive motion injuries, develop over a period of time as a result of repetitive stress, poor posture, vibration, or temperature extremes. Back pain, the most widely recognized problem is caused by repeated flexion, extension, and twisting of the trunk, as masons stoop to pick up materials and place them on the wall. Characterized by pain, soreness, and a burning sensation, tendinitis is the inflammation of a tendon and its sheath, caused by repetitive motions or strong, forceful grips. Carpal tunnel syndrome, which involves compression of the median nerve where it passes through the wrist, is characterized by pain and soreness in the hands and wrists, tingling, and numbness. The disorder can have several causes, including repetitive wrist motion, excessive wrist extension and flexion (bending the hand upward and downward), and excessive wrist twisting. ERGONOMIC SOLUTIONS The single most important recommendation to emerge from the research conducted concerns wall height and material placement in relation to the bricklayer. To minimize reaching and stooping, scaffolding should be raised frequently so the level of the wall masons are working on remains between their knees and chest. A variety of ergonomic products have been designed to help prevent or alleviate repetitive motion injuries: wrist supports, back support belts, and anti-vibration gloves.