Crunches vs. Planks – Which Are Best for Your Core?

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This is a question asked a lot and for good reason. Both exercises work muscles in the core, but one is a clear winner when it comes to building a solid core. But first, let’s take a look at each one separately.


When people think of crunches, they think of building a strong six-pack … and it will do that (provided your body fat percentage is low enough for them to show through). But doing crunches the normal way involves placing excess pressure on the weakest part of your back … the lower part, by flexing it forward.  A better style of crunch is with your spine straight (neutral) instead of bent forward (flexed). According to how the spine is built, it was never meant to be flexed, but kept in the neutral straight position. So the next time you do crunches, do them with your back straight from your shoulder to your butt.

How to Properly Do Sit-Ups and Crunches

Sit ups and crunches are two common core exercises that are often done incorrectly. Doing these exercises incorrectly can aggravate injuries or cause new ones. If you do them incorrectly, you’re also limiting or completely eliminating their effectiveness. You may think you’ve been doing crunches and sit ups correctly because you’ve been doing them the same way for years, but it’s never too late to correct your form. Below you’ll learn proper technique for doing both exercises, and you’ll learn what muscle groups each exercise targets.

Sit Ups

Sit ups are a classic exercise that you’ve probably been doing since primary school. If you played organized sports in a recreation league or through the school system, you’ve probably done your fair share of sit ups. Maybe you did sit ups while one of your parents did theirs. Chances are good that you’ve done sit ups before, but have you been doing them with proper form? Whether you have done sit ups or not, you will learn the proper technique for them now.

Sit ups target your core abdominal muscles, but they also work other muscles in your body. Sit ups activate abdominal muscles, and a variety of stabilizer muscles from your neck, through your chest, abdominal area, back, and in your upper legs. Since you use so many muscles when performing sit ups, it’s even more important to know how to do them properly.

To begin a sit up you will need to lay on your back with your knees bent and your feet on the floor. Your knees will be bent at about a 90-degree angle. To begin with, you will hold your arms straight out. They will be off of the floor and parallel to your body. Once you can do sit ups in this position, you will position your arms across your chest. After you master doing them with your arms across your chest, you will place your hands near your ears like you’re cupping them but you won’t be touching your ears. Most people have either done sit ups with hands behind your head, or you have seen someone else do this, but this can lead to neck strain and it’s not worth the risk.

Once you have the correct position, you will pull your upper body up into a sitting position. As you lift yourself up using your abdominal muscles and other stabilizer muscles, you will need to exhale your breath. Concentrate on contracting your abdominal muscles as you lift your body up, and it’s important that you lift yourself up in a smooth motion. You will leave your feet on the floor and knees will remain bent. Change your arm position to the position that makes it the most difficult for you, but allows you to keep proper form. Perform several sets of sit ups, resting between each set, for the best results.


Crunches are also a classic exercise, and many people have advocated that they take the place of the traditional sit up. Crunches are a great abdominal exercise, however, they use fewer muscles than a sit up, and should only replace sit ups in the case of back, hip, or other injuries that can be aggravated by a full sit up. Crunches target your abdominal muscles only, but many people believe they target abdominal muscles better than sit ups. Ideally, crunches and sit ups will both have their place in your exercise routine, but you’ll have to see what works best for you.

To perform a proper crunch, you will begin by laying on the floor with your knees bent at a 90-degree angle, just as you would for a sit up. Place your hands near your ears like you’re cupping them instead of locking your hands behind your head. Lift yourself head and upper body up in a smooth motion while exhaling your breath, and concentrate on squeezing your abdominal muscles as you perform the crunch. Unlike a sit up, you will keep the movement short, and you will only be activating your core muscles rather than using additional stabilizer muscles. While performing a crunch you will only be lifting your upper body up in a short, compact motion. You will keep your feet on the floor while performing your crunch. It may not seem like much motion, but if you concentrate on contracting your abdominal muscles while doing your crunch, you will be performing an excellent abdominal exercise.

Both sit ups and crunches are great abdominal exercises. Sit ups work more muscles, but may not be an option for some people. Crunches are perfect for strictly targeting abdominal muscles. No matter which exercise you choose, you can be sure that you’re now doing it correctly, using perfect form.


Planks on the other hand are meant to be done with the spine in the neutral position. Because planks are an isometric exercise where the angle of the joint does not change appreciably, they work most of the the heavy hitters of the core muscles – abs, obliques and erector spinea. However some other secondary core muscles are also worked including the deltoids, trapezius, rhomboids, in addition to the glutes and hamstrings.

By contracting your ab muscles, which draws them closer to your spine, you develop the abs, but you are also developing muscles that support your spine. So not only do you end up with a nice six-pack, but an overall better developed physique to frame your six-pack.

So to answer the question “Which is best for your core, crunches or planks?” planks win hands down. And the two main reasons are because they keep your spine straight and work more of the muscles that make up your core. Crunches will help develop the front of your core – the abs – but often at the expense of spine instability due to the flexing.

Plank Tips

When planking, keep these tips in mind:

• Keep your shoulders directly above your elbows when front planking
• Keep your hips in a straight line with your shoulders once in place
• Pull in your glutes and quadriceps
• Keep your hips high during the side plank to work the external obliques

If you have always done crunches, try planks instead and notice how your body responds.

4 Variations on the Classic Plank to Strengthen Your Core

The plank is an excellent bodyweight exercise for building core strength. If you have not tried it before, it may sound very simplistic. You lie face down on the floor as if you are going to do some push-ups. Instead of supporting yourself with the palms of your hands, you do it with your forearms.

Place your forearms on the floor where your elbows make 90 degrees angles. Supporting yourself with your forearms and your toes, keep your body perfectly straight from your ankles through your head. Suck your belly button towards your spine. Hold for 30 seconds.

The action of keeping your legs stiff and compressing your stomach muscles is not as easy as it sounds. If you really want to crank up the fat-burning and six packs abs creating ability of the plank, try the following variations on the traditional exercise. (Perform several repetitions each.)

Push-Up Plank

Begin in the classic plank starting position. Perform a push-up and stop at the top. Remember to keep your legs, spine and head in a straight line. Your palms should be face down on the floor directly under your shoulders. Since this is easier to do than a traditional plank and other variations, hold for 60 seconds, or as long as you can.

Hell Raisers

These are also known as plank up-downs. They combine the push-up plank with the traditional plank. Begin in the normal plank position. Then push up onto the palm of your left hand, then your right. Return to the starting position, in reverse order. Perform sets of 10.

Plank Jacks

Imagine a combination of jumping jacks and planks. That is exactly what you’re going to be doing. Get down in the traditional plank position. Except this time, bring your hands together in front of your face and interlace your fingers. Push up off of your toes, spread your legs in the air and land on your toes again. Aim for a width 6 to 8 inches outside of each of your shoulders. Bounce up off of your toes again, returning to the starting position. Practice sets of 10.

Side Plank

Perform a regular plank. Then rotate your body to the right so that you are only leaning on your right forearm. Swing your hand in under your body for support, keeping your elbow directly under your shoulder. Repeat on your left side. Your hips will have a tendency to drop to the floor. Pull them skyward, keeping the classic, rigid, straight body position from your toes to your head. Hold for 30 seconds.

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