Description:Let's face it, crunches are overrated. There are plenty of other exercises that work your abdominals while training the muscles in your back. When the front and back of your torso work together, it's a win-win situation for your core. This variation of the quadruped (named such since you're on all fours - get it?) also targets the obliques. Do 15 reps on each side to make set. Aim to do at least two sets to three sets.