Meet the AirLegs Human Exoskeleton: a system designed to make it easier for you to run. In fact, this augments your cardio by 10%. This is a backpack mounted system and uses pneumatic cylinders which move your legs for you. The next version is expected to be even more versatile.
AirLegs simply lets you run faster. This device was tested at the Army Research Laboratories in 2013. Jason Kerestes is behind this awesome project.