Oxygen consumption is an effective way to measure exertion during static muscle contraction. OSHA's preferred order from least effective to most effective abatements in the Hierarchy of Controls is: personal protective equipment; administrative procedures and policies; engineering controls; substitution and elimination The clutter-avoidance principle requires that there should be no space between components. There is good evidence that the Union Carbide disaster releasing methylisocyanategas in Bhopal India due limited alarms and controls was the worst industrial accident in modern history (1900 on). Classroom based training is a near to task performance support intervention. Redundancy should be avoided as much as possible in the design of display and controls. Both aerobic and anaerobic metabolism supply ATP to muscle cells. Fitt's law, which applies to hand, arm and foot movements, uses the Index of Difficulty, which is a ratio of double the movement amplitude divided by the size of the target width (2A/W). Shift work schedule designers need to be aware of how disrupting the natural humantendency to sleep at night and be awake during the day has on employees. The social model reframes disability, stating that the actual environment disables people by its design.