Here’s one of my favorite ab moves that has stood the test of time in my arsenal of abdominal exercises. I first learned this in kickboxing back in college, but it works so well that I still do it today.

Start with your feet flat on the floor and lean back until you start to feel your abs working. Punch your right fist toward your left knee as you twist slightly to the left. Reverse to punch your left fist toward your right knee as you twist slightly to the right. Repeat 12 times. Do three sets. You’ll work your entire core, especially your obliques.

For an added burn, lift you feet off the ground so you’re balancing on your sit bones. Pick up your pace to double time–twist and punch left to right until you have to stop.