Attention cyborg wonks and lazy people: Japanese scientists at Tsukuba University have created a motorized knee that you can attach to your leg to increase your muscle power and running speed. The 11-pound kit’s weight is shared by an exoskeleton-like attachment for your leg and a power source that’s carried in a small backpack. But here’s the best part: the device is not designed with any kind of rehabilitation or handicap-assisting function in mind; it’s simply to make it easier for regular folks to run faster!

The knee assistant allows a runner to jog at a steady 4.7 miles per hour with 30 percent less muscle power than they would normally need. A sensor in the device detects the degree of flex in the knee, informing a small motor how much assistance is needed. The team who developed it is enthusiastic about an even lighter device being commercialized within three years. The question is: for what customer?

Most everyone who runs for leisure runs to build muscle and endurance in the legs, so its unclear why runners would want to increase the efficiency of their jogs only to prolong them. There is also no mention of how much the added 11 pounds cancels out the benefit of 30 percent reduction in muscular effort. But unless the NFL declares the leg eligible for league play, it’s unclear exactly who is going to benefit from this (likely expensive) device.

But the Tsukuba U. group isn’t all about superfluous robotic augmentations, and we’ll forgive them the apparent lack of constructive uses for the robotic knee because of their previous development of the Robot Suit HAL (Hybrid Assisted Limb), which is essentially a cyborg suit that helps paralyzed people learn to get around again. If for every innovation like HAL they want to create a robotic limb enhancement with no obvious use beyond recreation, we won’t hold a grudge.