At Nagasaki University in Nagasaki-City, Japan, mechanical engineer Shunji Moromugi straps on a pair of what he calls "power pants" and gets to work. Holding a 16-kilogram barbell on his shoulders, he does 90 squats in 90 seconds without breaking a sweat. That's because the pants contain computerized sensors that detect what his legs are doing-deep knee bends-and tubelike artificial muscles, mounted on both sides of the knee, that expand and contract with flows of compressed air. The artificial muscles are attached to a steel brace that spans the thigh and calf; when they lengthen, they extend Moromugi's knee and help him stand more easily.

Select from the choices above to read the entire article.