Take your abs workout to the next level! By adding a foam roller, you'll force your core to work harder to help balance your body on the unstable surface.
Try this marching crunch exercise: Lie on the roller (it should line the length of your spine), with your knees bent, feet flat on the floor. Clasp your hands behind your head, elbows out [as shown]. Lift your head and shoulders off the roller, and slowly try to lift your right foot slightly off the floor. Step it back down and switch to the left. Continue marching your feet, alternating legs each time, for a total of 10 reps.
Tip: Try to keep your pelvic floor muscles engaged the entire time. The easiest way to do? Imagine that you really need to pee but have to hold it in.
Click here for another challenging core exercise called 90 90 butterfly.