University of Michigan researchers have made a robot that runs. Her name is MABEL. It's the only robot, they say, that can run like a human. From the University's site:
Its weight is distributed like a person's. It has a heavier torso and light, flexible legs with springs that act like tendons. MABEL is in the air for 40 percent of each stride, "like a real runner," Grizzle said. Other running robots are almost speed-walking. Their so-called flight phase when both feet are off the ground lasts for less than 10 percent of each step.
"We envision some extraordinary potential applications for legged robot research: exoskeletons that enable wheelchair-bound people to walk again or that give rescuers super-human abilities, and powered prosthetic limbs that behave like their biological counterparts," said developer Hurst, who is now an assistant professor in the Department of Mechanical, Industrial and Manufacturing Engineering at Oregon State University.