5. Side oblique crunches
Side oblique crunches are a great way to train your obliques. Start in a side plank position for the more challenging version of the exercise. Put your hand behind your head and crunch your body to the side. When you move your head down, your torso goes up, and when you move your head back up, your torso goes down.
Do this for 50 seconds, then take a 10-second break.