Let me explain: Find a crack, put a rope down or get artistic with a piece of sidewalk chalk. However you create a line, start to one side of it with your legs together and knees softly bent. Keeping your legs together, jump across the line, landing softly on the balls of your feet to protect your knees and ankles.
Jump back to the other side and repeat. Count reps or time it—it's entirely up to you. Essentially, the faster you move, the more you'll burn. And if it gets too easy, you can replace the line with something taller, like a dumbbell or a shoebox. Or jump with one leg instead of two. But like any jumping move, you'll need to maintain proper form to prevent injury. And if you have knee issues, you just might want to skip this lower body blaster.