The idea makes sense: You're moving your legs, working your muscles, but since you're in water, you're doing so without the pounding of a regular run, whether that be on a treadmill or the road, with the added benefit of increased resistance from the water. Still, Hydrophysio's aquatic treadmill looks a bit over-the-top. Not to mention that it would give the less dedicated among us too much opportunity to back out and think of something else to do while waiting for the machine to fill up with fluid. Now, if it doubled as a jacuzzi, so you could finish your workout, grab some Gatorade, and then return a few minutes later to find it warm and bubbling, that would be something. One bonus: It works for rehabbing your pets, too. So, you know, you could walk your dog, in the water, without going outside. Because that's what technology's for. —Gregory Mone
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.