If you really want to increase your burn, grab a weighted vest! 

Beginners: 3 Rounds - 30 Seconds Work | 10 Seconds Rest

Intermediate: 3 Rounds - 50 Seconds Work | 10 Seconds Rest

Advanced: 4 Rounds - 50 Seconds Work | 10 Seconds Rest

1. Mountain Climbers

Assume a press up position so your hands are directly under your chest at shoulder width apart with straight arms. Your body should form a straight line from your shoulders to your ankles. Lift your right foot off the floor and slowly raise your knee as close to your chest as you can. Return to the starting position and repeat with your left leg

2. Double High Knees

A little nod to Melissa here - Start by performing high knees like you regularly would by running in place, bringing your knees up to your chest as high as you can & making contact with your hands. After making contact between your right knee and your right hand & your left knee and your left hand. Raise your right foot up towards your left knee & make contact with your left hand. Then raise your left foot towards your right knee and make contact with your right hand. This is ONE rep. Try to land on the balls of your feet as you run and switch legs as fast as you can.

3. Jump Squats

Stand with your feet shoulder-width apart. Start by doing a regular squat, then engage your core and jump up explosively.When you land, lower your body back into the squat position to complete one rep. Land as quietly as possible, which requires control.

4. Spider Plank

Start in the plank position with your arms fully extended, and rotate one hip outward, drawing your knee up toward your elbow. Return to the starting position and repeat on the opposite side.

5. Criss Cross Jacks

Stand with feet together and take a deep breath in. As you exhale, jump feet out wide and cross arms overhead. From there, scissor legs, crossing left leg in front of right. Immediately repeat, alternating sides each time.