The 3 Best Core Exercises: The Most Efficient, Effective, and Easily Modified

Most often when you see “ab-slimming exercises” advertised, the claim is that the moves will slim the stomach by targeting the muscles there: your abs. But contrary to what many people believe, developing strong abs will not slim your stomach.

In other words, “ab-slimming exercises” are not possible.

What a strong core will do, though — no matter your current size or fitness level — is strengthen your back, improve your balance, better your posture, assist in avoiding injury, and help you be an overall fitter person. As the name implies, your core is at the center of your body, and it arguably encompasses the most important set of muscles you have.

So, if you’re ready to work your core for a better back, improved posture, and all the other real benefits, great! But here’s one other thing to keep in mind: not all core exercises are alike. We’ve all done our fair share of crunches and sit-ups, but let’s be honest, they’re not super effective. Plus, do any of us have all day to dedicate to core exercises?

You need something more effective and more efficient — ab moves that will get the job done with a limited number of reps.

So, without further ado, here are the only three core exercises you’ll ever need:

1. The Bicycle

We’re starting with a challenging and effective move that’s still fairly easy to master. Plus, you can modify it to accommodate your fitness level. As you improve and notice more strength in your core, increase the difficulty of the move so you can continue to challenge yourself and see results.

Equipment Needed:

• An exercise mat

How to Do It:

1. Start by lying on your back on the mat with your knees and feet lifted off the ground at a ninety-degree angle.
2. Lace your hands behind your head to cradle your neck and head, but do not pull on your neck and head. Allow your elbows to fall out to the sides.
3. Start by raising your shoulders and upper back up off the mat and leaning slightly to the left. At the same time, bring your left knee toward your chest, so your left knee and your right elbow come together.
4. Do the same with the other side by bringing your right knee and your left elbow together.

How Many to Do:

Connecting your left knee and right elbow once and your right knee and left elbow once equals one rep. Said another way: left plus right equals one. Build up to 3 sets of 10 to 15 reps. Rest between sets.

How to Make It Harder:

• To challenge yourself even more, when you reach the peak of one crunch (with elbow at opposite knee), stay there. You can either hold for a 5-count or do 5 extra “mini crunches” at this contracted position.
• Another way to increase difficulty is to extend your legs beyond ninety-degrees. The straighter and lower your “free” leg is, the harder this move will be.

2. The Russian Twist

An oldie but a goodie — a real goodie. This move will strengthen the obliques for a strong core that you’ll actually be able to feel when you move. It’s also an essential move for strengthening the muscles near your spine and alleviating back pain. Again, this move can be modified to fit your fitness level.

Equipment Needed:

• An exercise mat
• Weights (optional)

How to Do It:

1. Start seated with knees bent at roughly a ninety-degree angle and feet flat on the mat.
2. Lean your upper body back so it’s at a roughly 45-degree angle with the floor.
3. Bend your elbows and hold them out in front of your body or cross them in front of your chest if you prefer.
4. Start moving only your trunk to the left. Keep your core tight and contracted, and make sure you aren’t just moving your shoulders and head. You should be rotating your entire top half to the left (as far as you can safely go), and your bottom half should remain frozen.
5. Return to center position, and repeat to the right.

How Many to Do:

A twist to the left and a twist to the right counts as one rep. Said another way: left plus right equals one. Build up to 3 sets of 8 to 12 reps. Rest between sets.

How to Make It Harder:

• To challenge yourself, raise your feet up instead of resting them on the mat while you twist.
• You can also try holding a weight in both hands near your chest and twisting with it. A medicine ball or bumper plate will work best.

3. The Towel Plank and Knee-In

This one’s a favorite of boot camp instructors the world over because it’s hard. Not only are you improving the strength of your core by forcing the lower abdominals, obliques, and lats to extend and pull, you’re also strengthening your glutes, quads, and hamstrings.

This movement is the definition of a full core exercise. According to the Mayo Clinic, a core exercise is one that works the muscles of the abdomen, pelvis, hips, and lower back so they can all work in harmony. And again, once you master this move, there are lots of ways to play around with it so you’re always challenged.

Equipment Needed:

• An old hand or kitchen towel
• A sleek floor surface, like wood, laminate, or relatively smooth tile
• Athletic shoes (no bare feet or socks on this one)

How to Do It:

1. Fold your towel so there’s enough room for you to place both your feet on it. Set the towel on your slick floor surface, and stand on it, hip-distance apart.
2. Now, crouch down or bend at the waist and slowly walk your hands out in front of you so you end in high plank position. If you’re unsure of the proper way to do a plank, check out this video. Your wrists, elbows, and shoulders should all be aligned at a ninety-degree angle with the floor, and your neck and back should be as flat and in-line with your hips and legs as possible. Knees should be straight.
3. Stabilize your hands in plank position and contract your abs and glutes. Now, slowly pull your bottom half toward your chest by pulling your feet across the floor with the towel. Your feet should stay on the towel the entire time.
4. Once you’ve brought your legs up to a crouching position, slowly slide your feet back to the high plank position.
5. Your hands should remain static in plank position the whole time. Your feet should stay on the towel the whole time. Keep your neck and head parallel with the floor.

How Many to Do:

Legs to chest and back is one rep. Build up your endurance to 3 sets of 10 to 15 reps. Rest between sets.

How to Make It Easier and Harder:

• If high plank is too difficult for you, you can stay in low plank (with elbows and forearms on the ground). You can also bring in just one leg at a time (you’ll need two towels).
• If you’d like to challenge yourself, try bringing your legs to the side instead of pulling them directly to your chest. Do your 10 to 15 reps on just one side only before resting and switching to the other.

The True Benefits of Core Exercises

Remember that a tight core isn’t all about looks. Sure, most of us want a flat tummy for aesthetic reasons, but having a strong core can also better your balance, banish back pain, prevent injury, and improve your posture.

The key is to not waste your time and energy on ab workouts that aren’t effective. With the three core exercises above, that’s not a concern. The bicycle, the Russian twist, and the towel plank knee-in are fundamental moves that will immediately start helping you achieve and maintain that strong core you’ve always wanted.

Becca Borawski Jenkins

Becca earned her MFA in Cinema-Television Production at USC’s famed film school, and her first career was as a music editor. Becca found her way to career number two through martial arts. She trained in BJJ and muay Thai and worked with professional MMA fighters, building websites, organizing fight promotions, and producing videos.

In 2005, she became a student at CrossFit Los Angeles where she met WLC co-founders Andy Petranek and Michael Stanwyck. In only a couple years, she became CrossFit Level III Certified, left her entertainment career, and dedicated herself full time to coaching, serving as the Program Director of CFLA and founder of the CFLA CrossFit Kids program. After seven years as a music editor and then eight years as fitness instructor, Becca segued to her current career — full-time editor and writer.