(b) Stand up using just your right leg. Once you’ve managed this, jump (from one leg, landing on two) back into plank position and repeat on the other side. Do 3 reps on each leg.

SpaceX's Grasshopper, intended to be a reusable rocket, recently tripled its previous mark of 263 feet by going up to 840 feet. It then lands in the spot it took off from. Standard rockets are ...

What goes up, must come down. And sometimes, the trip back to Earth is just as important as the flight itself. That’s what SpaceX proved recently when its 10-story Grasshopper rocket flew nearly ...