Cross jacks are an excellent way to get your heart rate up, but this variation of jumping jacks really rocks your inner thighs, making it an awesome toning exercise, too!

Here's how to do it — no need for equipment, a gym, or even much space in your home. Get ready to sweat!

• Stand with your feet shoulder-width apart and extend your arms straight out to either side with palms facing down. This is the starting position.
• Jump and cross your right arm over your left and your right foot over your left. Jump back to the starting position, then cross with the opposite arm and foot. This counts as one rep.
• Continue alternating sides and repeating this movement until you complete 25 reps. Be sure to keep up the pace and don't allow too much time for recovery between jumps — this way you'll be sure to keep up your heart rate and engage your whole body.