Wheelchairs: Chairs mounted on wheels and designed to be propelled by the occupant.Man-Machine Systems: A system in which the functions of the man and the machine are interrelated and necessary for the operation of the system.Paraplegia: Severe or complete loss of motor function in the lower extremities and lower portions of the trunk. This condition is most often associated with SPINAL CORD DISEASES, although BRAIN DISEASES; PERIPHERAL NERVOUS SYSTEM DISEASES; NEUROMUSCULAR DISEASES; and MUSCULAR DISEASES may also cause bilateral leg weakness.Architectural Accessibility: Designs for approaching areas inside or outside facilities.Equipment Design: Methods of creating machines and devices.Ergometry: Any method of measuring the amount of work done by an organism, usually during PHYSICAL EXERTION. Ergometry also includes measures of power. Some instruments used in these determinations include the hand crank and the bicycle ergometer.Electric Power Supplies: Devices that control the supply of electric current for running electrical equipment.Quadriplegia: Severe or complete loss of motor function in all four limbs which may result from BRAIN DISEASES; SPINAL CORD DISEASES; PERIPHERAL NERVOUS SYSTEM DISEASES; NEUROMUSCULAR DISEASES; or rarely MUSCULAR DISEASES. The locked-in syndrome is characterized by quadriplegia in combination with cranial muscle paralysis. Consciousness is spared and the only retained voluntary motor activity may be limited eye movements. This condition is usually caused by a lesion in the upper BRAIN STEM which injures the descending cortico-spinal and cortico-bulbar tracts.Spinal Cord Injuries: Penetrating and non-penetrating injuries to the spinal cord resulting from traumatic external forces (e.g., WOUNDS, GUNSHOT; WHIPLASH INJURIES; etc.).Self-Help Devices: Devices, not affixed to the body, designed to help persons having musculoskeletal or neuromuscular disabilities to perform activities involving movement.Disabled Persons: Persons with physical or mental disabilities that affect or limit their activities of daily living and that may require special accommodations.Ischium: One of three bones that make up the coxal bone of the pelvic girdle. In tetrapods, it is the part of the pelvis that projects backward on the ventral side, and in primates, it bears the weight of the sitting animal.Pressure Ulcer: An ulceration caused by prolonged pressure on the SKIN and TISSUES when one stays in one position for a long period of time, such as lying in bed. The bony areas of the body are the most frequently affected sites which become ischemic (ISCHEMIA) under sustained and constant pressure.Walkers: Walking aids generally having two handgrips and four legs.Tennis: A game played by two or four players with rackets and an elastic ball on a level court divided by a low net.Human Engineering: The science of designing, building or equipping mechanical devices or artificial environments to the anthropometric, physiological, or psychological requirements of the people who will use them.Track and Field: Sports performed on a track, field, or arena and including running events and other competitions, such as the pole vault, shot put, etc.Basketball: A competitive team sport played on a rectangular court having a raised basket at each end.Canes: Sticks used as walking aids. The canes may have three or four prongs at the end of the shaft.Elevators and Escalators: Mechanical ascending and descending devices which convey objects and/or people.Equipment Safety: Freedom of equipment from actual or potential hazards.Shoulder: Part of the body in humans and primates where the arms connect to the trunk. The shoulder has five joints; ACROMIOCLAVICULAR joint, CORACOCLAVICULAR joint, GLENOHUMERAL joint, scapulathoracic joint, and STERNOCLAVICULAR joint.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Maintenance: The upkeep of property or equipment.Sports: Activities or games, usually involving physical effort or skill. Reasons for engagement in sports include pleasure, competition, and/or financial reward.Acceleration: An increase in the rate of speed.Robotics: The application of electronic, computerized control systems to mechanical devices designed to perform human functions. Formerly restricted to industry, but nowadays applied to artificial organs controlled by bionic (bioelectronic) devices, like automated insulin pumps and other prostheses.Musculoskeletal Physiological Processes: Biological actions and functions of the MUSCULOSKELETAL SYSTEM.Crutches: Wooden or metal staffs designed to aid a person in walking. (UMDNS,1999)Locomotion: Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.Motor Vehicles: AUTOMOBILES, trucks, buses, or similar engine-driven conveyances. (From Random House Unabridged Dictionary, 2d ed)Upper Extremity: The region of the upper limb in animals, extending from the deltoid region to the HAND, and including the ARM; AXILLA; and SHOULDER.Hemiplegia: Severe or complete loss of motor function on one side of the body. This condition is usually caused by BRAIN DISEASES that are localized to the cerebral hemisphere opposite to the side of weakness. Less frequently, BRAIN STEM lesions; cervical SPINAL CORD DISEASES; PERIPHERAL NERVOUS SYSTEM DISEASES; and other conditions may manifest as hemiplegia. The term hemiparesis (see PARESIS) refers to mild to moderate weakness involving one side of the body.Arm: The superior part of the upper extremity between the SHOULDER and the ELBOW.Activities of Daily Living: The performance of the basic activities of self care, such as dressing, ambulation, or eating.