Are Planks Better Than Crunches for Abdominal Development?

image of Cathe Friedrich doing a planks to strengthen her core in Fit Split Boxing & Boot Camp

For years, crunches have been the “go to” ab exercise. If you wanted ab definition, you did more crunches, or so we thought. Yet we now know that crunches alone aren’t enough to get abs to “pop.” Even the best defined abdominal muscles won’t show if you have a thick layer of fat covering them. In fact, if your body fat percentage is higher than 20%, you won’t have substantial ab definition no matter how well developed your ab musculature is. The first order of business, of course, is to lose body fat and then work on strengthening and hypertrophying the abdominal muscles. That’s when you’ll get the ab definition you’re looking for.

Even if you have a low enough body fat percentage for your abs to show, crunches aren’t the only exercise that work the abs. Planks and their variations also work the abdominal muscles as well as a variety of other muscles that make up your core. In fact, planks are growing in popularity as an alternative way to work the abs. Are planks actually better than crunches for developing abs?

Crunches versus Planks: Which is Best?

First, what is the difference between these two exercises? The main distinction between crunches and planks is that planks are an isometric exercise, one where you hold a position against gravity until the muscles fatigue without actually shortening the muscles. In contrast, when you do crunches, your spine flexes and muscles that make up your abs actively contract. Crunches primarily work the external abdominal muscles, the rectus abdominus, and the external obliques. In contrast, planks work multiple muscle groups, including the internal obliques, the deep transverse abdominus, and the stabilizing muscles in your hips and back. Even your shoulders get in on the action when you hold a plank or one of its many variations.

No doubt, you’re working MORE muscles when you do planks and you’re targeting important ones that stabilize your spine and protect you against back injury. In contrast, crunches force your spine to flex, and for people with spinal issues, this is risky. So, crunches place stress on your spine while planks strengthen the stabilizing muscles that support your spine and help keep your back healthy. So, one is more back and spine-friendly than the other.

Ab Hypertrophy

But, what about the issue of ab development? Not all experts agree that planks alone are enough to build ab definition. Dr. Wayne Wescott who co-wrote the American Council on Exercise’s Guide to Youth Strength Training believes that planks don’t work the abdominal muscles to the point where they truly fatigue. You have to hold a plank too long to exhaust the muscles enough to hypertrophy them or make them stronger.

Crunches don’t work as many muscle groups as planks but they hit the external rectus abdominus muscles and the external obliques hard, the ones that give your abs definition when they’re developed. Plus, the crunch is an isotonic movement that involves the shortening of the muscles against gravity. Why is this important?

In general, isotonic exercises are more effective for muscle hypertrophy than isometric ones. So, crunches should still be part of your routine but shouldn’t be the only exercise you do to target your abs. It’s also important to vary your crunches. EMG studies show that the bicycle crunch is particularly effective at activating the external ab muscles. Plus, it’s a dynamic exercise that burns more calories than a standard crunch.

How about an exercise ball? Doing crunches on an exercise ball changes the angle at which you work your superficial ab muscles. When you’re recovering between strength-training exercises, do a set of standing crunches to work your abs and keep your heart rate up. Of course, you’ll want to balance things out with reverse crunches as well. Give your abs some variety! They’ll love you for it and thank you by growing more defined.

You Still Need Planks!

Although planks aren’t the BEST for hypertrophying your superficial ab muscles, they are vital for strengthening the other muscles in your core region. Using planks to strengthen your entire core, particularly your back, will help protect against injury when you do other abdominal exercises and when you do everyday activities, like bending over to pick something up or lifting something heavy. Abdominal crunches alone won’t do that.

Plus, planks are a safer exercise for your back than crunches since you aren’t flexing your spine. Yes, you can get injured doing planks, especially if you have shoulder issues, but the risk is lower of hurting your back unless you use terrible form. You can also make up for some of the shortcomings of planks by doing more advanced versions. Start by mastering a standard plank. Once you can hold the position for a minute, try more advanced versions. The list of plank variations is extensive but ones to try include side planks, walk-out planks, and reach-through planks. Increase the balance challenge by doing one-arm and one-leg planks. A more advanced variation is the bird dog plank.

An ACE Fitness study measured EMG activity of the abdominal musculature and found the exercises that activated the muscles most were (in order):

·       Bicycle maneuver

·       Captain’s chair

·       Crunches on exercise ball

·       Vertical leg crunch

·       Torso Track

·       Long arm crunch

·       Reverse crunch

·       Crunch with heel push

·       Ab Roller

·       Hover

·       Traditional crunch

·       Exercise tubing pull

·       Ab Rocker


The Bottom Line

As you can see, there are lots of exercises that work your abs! The most effective ways to get your abdominal muscles to show is to use a multi-pronged approach. Do a variety of planks and crunches, assuming you’re orthopedically sound and don’t have back problems. Then, mix it up and do variations of planks to change the stimulus you place on your muscles. Do sets of ab rollouts, a proven activator of the rectus abdominus muscles, and hanging leg raises. Don’t let your abs get complacent!

Add some fat-burning cardio, including moderate-intensity cardio and high-intensity interval sessions. Also, don’t forget about nutrition. Even the best-developed abs won’t show if your body fat percentage is too high. You may already have abs in hiding and just need to lower your body fat percentage enough for them to show.



ACE Fitness. “Reality Check: Are Planks Really the Best Core Exercise?”
ACE Fitness. “American Council on Exercise (ACE)-sponsored Study Reveals Best and Worst Abdominal Exercises”


Related Articles by Cathe:

Signs You Have Weak Core Muscles and How to Power Up Your Core

Abdominal Exercises: Are You Doing Too Many Reps?

Ab Training: Can the Quest to Get Defined Abdominals Lead to Back Pain?

Flabby Abs? It Could Be Bad Posture. Find Out What to Do About It


Related Cathe Friedrich Workout DVDs:

Abs/Core Workout DVDs



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