Feeling a little slow on that run?  What if there was a device you strap on to your ankle that could help give you a boost?   Engineers at Stanford University, with funding from the National Science Foundation, are studying ways to improve the runners’ experience.  The team investigated two different modes of running assistance:  motor-powered and spring-based.   Eleven experienced runners strapped on this ankle exoskeleton and took to the treadmill to test the two assistance types.    The energy savings the researchers observed indicate that a runner using the powered exoskeleton could boost their speed by as much as 10 percent. The team thinks it should be possible to turn the powered skeleton into an effective untethered device to give runners a little kick to their step, without breaking a sweat.  While more research is required, the team is thrilled about how well the device has performed.