The cost of low back pain totals more than $100 billion every year in the United States. Staggering, right? Especially when you consider that the solution is often completely free. Core stability exercises -- like planks and bird dogs -- can significantly decrease low back pain, a new meta-analysis in the prestigious journal PLOS One confirms. They're also a great way to strengthen your core and sculpt six-pack abs.



One of our favorite core stability exercises is the side plank with rotation. Watch the video below to see how it's done:



To perform the exercise, lift your body into a side plank, and then rotate your torso as you reach underneath your body with your free arm. “The rotation adds a whole other dimension of stability and range of motion to the side plank. When you reach under, you’re going to want to fall over, so you have to lock in your core and really engage your obliques,” says Jeremy Frisch, U.S.A.W., owner of Achieve Performance Training and creator of the 24-Hour Arms Workout, now available on Men’s Health Personal Trainer. (Click here to try the online diet and fitness tool free for 30 days!)