Once you've mastered the side plank, it's time to push your limits even more. This variation will seriously challenge your core, work your arms, and test your balance. If you've ever seen a strong and powerful yogi move into this shape and thought it in your wheelhouse, follow these step-by-step instructions, and prepare to amaze yourself.

• Begin in a plank position (the top of a push-up) and roll to your left side, allowing your feet to roll too, so you're balancing on the outside of your left foot and the inside of your right.
• Reach your right arm toward the ceiling and lift your waist away from the floor to make your obliques fire away. Press your left inner thigh up into your right inner thigh; this helps stabilize you even more.
• Balance your right hand and the outside edge of your right foot. Flex both feet, and lift your left arm straight in the air.
• Keeping your spine lengthened and your abs engaged, lift your left leg up as high as you can without letting your waist sink to the ground. Then slowly lower your right leg back to the starting position. This completes one rep.