5 Oblique Exercises to Make Your Next Core Workout More Challenging (and Interesting)

If you've ever gone for a walk, reached over to grab your phone from the nightstand, or swung a stick at a piñata, then you've felt your obliques at work. They are, after all, essential muscles for everyday life, function, and movement.

In a perfect world, the whole core (a group of many muscles) should work like a symphony, says Patricia Ladis, PT, CBBA, founder of WiseBody PT and co-author of The Wise Woman's Guide to Your Healthiest Pregnancy and Birth. "The diaphragm is the conductor, starting the message for the symphony to play by activating the transversus abdominis first and then allowing the proper movers—the obliques and/or rectus abdominis muscle—to engage." For that to happen, you need to train your entire core. Unfortunately, folks tend to focus on the rectus abdominis, the outermost area of the abs responsible for the six-pack, says Jess Sims, a fitness instructor at Peloton. But there is more to your abs than just that outermost, or superficial, layer.

The obliques, for instance, which run diagonally on either side of the waist from the ribs to the hips, are important for overall body function, too. Made up of an inner and outer set, the obliques are actually the largest of the ab muscles. Their function: "to rotate, side-bend, and move the trunk, as well as to help with breathing," Ladis says. The obliques also play a roll in keeping your torso from twisting, to stabilize and, subsequently, protect your spine.

If your obliques are weak or underutilized, other parts of your body will try to compensate, potentially leading to discomfort or pain. The lower back is one area that often takes a big hit. In fact, a Journal of Physical Therapy Science study found that incorporating oblique exercises helped reduce chronic back pain, a condition that affects more than 50 percent of people in the United States.

How to Know If Your Obliques Are Strong Enough

Want to know if your obliques are up to par? Test them by doing bicycle crunches, suggests Ladis. "You should be able to curl your elbow to the outside of your bent knee, truly rotating the body. If you cannot curl past your midline then you do not have adequate control and strength in these muscles." You can also get into a side plank. "If your hips sag down, or your body twists or rotates in one direction it can mean your obliques are not working together and are weak." Improper breathing, breath holding, and ribs flaring out are also signs of oblique weakness, adds Ladis.

Whether yours are holding up their end of the bargain or not, Sims advice is that everyone incorporate exercises that target the obliques into their workout routine, but "especially if you have weakness in rotating your core or preventing it from being rotated." Luckily, there are tons of different options from Russian twists to standing side crunches that get the job done. To help shore up yours, Sims suggests these five oblique-strengtheners.

5 Oblique Exercises to Try at Home