Have you ever done a Frogger? In one fell swoop, you'll strengthen your core and tone up your glutes. This plank-to-squat move seems simple, but you'll feel it as you do your 30-second bursts. Here's how it works, in two steps:

• Begin in a plank position with your hands underneath your shoulders, body in one straight line. Jump your feet to the outside of your hands, coming into a deep squat and keeping your hands on the floor.
• Jump your feet back to a plank.

Related: How to Build Up to a Burpee [1]