The kneeling cable crunch is an ab exercise involving a cable machine.

Unlike most ab exercises, such as the sit-up, hanging leg raise, and ab wheel rollout, the cable ab crunch allows you to gradually add resistance to the exercise, which is vital for gaining muscle and strength.

And because it’s so effective for building muscle and strengthening your core, it’s particularly effective for increasing core stability, which can lower your injury risk and boost athletic performance. 

In this article, you’ll learn what cable crunches are, how to perform them correctly, the most common mistakes people make while performing crunches with cables, the benefits of the exercise, which muscles it works, the best cable ab crunch alternatives and variations, and more. 

What Are Cable Crunches?

The cable crunch, or “cable ab crunch,” is an ab exercise performed using a cable machine. 

To execute it, kneel facing a cable machine with the pulley set high and the rope handle attached. Hold one end of the rope in each hand in front of your head, then bring your elbows to your thighs by curling your torso and “crunching” your abdominal muscles.

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How to Do the Cable Crunch 

To learn how to perform cable crunches with proper form, split the exercise into three parts: set up, crunch, and extend.

1. Set up

Adjust the pulley on a cable machine to the highest setting and attach the rope attachment. 

While facing the cable machine, grab one end of the rope in each hand, take a step back to support the weight, then kneel on the floor (you can kneel on a pad or yoga mat for comfort if necessary).

Pull the rope down until both ends are in front of your forehead, then adjust your body so that your thighs are perpendicular to the floor and your shoulders are ahead of your hips.

2. Crunch

Without moving your arms or hips, pull your elbows to your thighs by rounding your spine. 

3. Extend

Reverse the movement and return to the starting position. 

As you extend, allow your spine to arch slightly until you feel a stretch in your abs.

Common Cable Crunch Mistakes

1. Maintaining a flat back.

The problem: Keeping a flat back during crunches with cables predominantly trains the hip flexors and minimizes how much the abs contribute, reducing the exercise’s effectiveness.

The fix: To ensure you train your abs through a full range of motion, focus on curving your spine as you crunch down, allowing your abs to fully contract, then slightly arching your back at the top of each rep.

2. Pulling with your arms.

The problem: Using arm strength instead of core strength to pull the weight down diminishes ab muscle engagement, limiting the muscle-building potential of the exercise. 

The fix: Keep your arms stationary and use your abs to pull the weight toward the floor.

3. Moving your hips

The problem: Moving your hips during cable crunches creates momentum, making the exercise less challenging and limiting the development of your abdominal muscles. Excessive hip movement can also increase your risk of “tweaking” your lower back.

The fix: Keep your hips stationary by ensuring your thighs remain perpendicular to the floor throughout the entire range of motion.

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The Benefits of Cable Crunches

1. They train your entire core. 

Cable crunches train all the muscle groups in your abdominal region, including the rectus abdominis and obliques.

2. They allow you to progressively overload your abs.

Unlike most ab exercises, the cable ab crunch allows you to increase the weight you lift as you get stronger, which is vital for maximizing muscle and strength gain.

3. They increase core stability. 

Core stability refers to the ability to control your torso during movement. A stable core is crucial for preventing back pain and improving athletic performance.

An effective way to increase core stability is to strengthen the muscles in your midsection that stabilize your spine, something cable crunches can improve

In other words, regularly doing cable crunches can make day-to-day tasks easier, decrease injury risk, and boost athletic performance. That’s why I perform them regularly and recommend people do them as part of my fitness programs for men and women, Bigger Leaner Stronger or Thinner Leaner Stronger.

(If you aren’t sure if Bigger Leaner Stronger or Thinner Leaner Stronger is right for you or if another strength training program might be a better fit for your circumstances and goals, take Legion Strength Training Quiz, and in less than a minute, you’ll know the perfect strength training program for you. Click here to check it out.)

Muscles Worked by the Cable Ab Crunch

Crunches with cables primarily train the rectus abdominis, the large muscle responsible for flexing the spine that, when well-developed and coupled with a low body fat percentage, gives you “six-pack abs.” 

They also train the obliques to a lesser degree, making the kneeling cable crunch an effective exercise for developing defined abs and a strong core

Here’s how the muscles worked by the cable ab crunch look on your body:


The Best Cable Crunch Variations and Alternatives

1. Standing Cable Crunch

The standing cable crunch is a more dynamic variation of the kneeling cable crunch. To perform it, stand in front of a cable machine with the pulley set above head height and the rope attachment secured. Step backward to support the weight and pull the rope down until the ends are in front of your face, then bring your chest towards your pelvis while keeping your hips and legs stationary.

The main difference between the standing and kneeling cable crunch is that the standing variation demands significantly more stabilization from your entire body. It’s also a great option for individuals who have knee discomfort or prefer a standing position for their exercises.

2. Seated Cable Crunch

Because you perform the seated cable crunch on a bench, many find it more stable than the standing or kneeling versions. This can help you develop a better mind-muscle connection since you can think less about stability and concentrate on the muscles you want to train. 

Sitting on a bench also limits hip movement, which can help those who find it challenging to keep their hips stationary during the exercise, and it can be more comfortable for those with knee issues who find kneeling painful.

3. Machine Crunch

The machine crunch is a cable crunch alternative involving an ab crunch machine. The main benefits of using the crunch machine are that it removes any instability, encourages you to use your abs rather than your hips to crunch the weight down, and places minimal strain on your back and neck, making it a good option for beginners or those with previous injuries.

4. Weighted Sit-up

Adding resistance to the regular sit-up by holding a weight plate or dumbbell enables you to progressively overload your abs without a specific machine. As such, the weighted sit-up is a viable alternative for those with minimal equipment (if you train at home or while traveling, for example).

That said, holding a weight can be awkward, so I only recommend the weighted sit-up if you have no other options. 

5. Bodyweight Crunch

Bodyweight crunches are easy to learn, require no equipment and little space, and help you build a foundation of core strength, making them ideal for beginners. However, one of the limitations of the bodyweight crunch is the inability to add extra weight.

This means that once you can comfortably perform about 30 reps per set, its potential for building muscle and increasing strength diminishes. At that point, you would need to perform more advanced crunch alternatives (like those outlined above) to continue progressing.

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FAQ #1: Are cable crunches effective?

Cable ab crunches are highly effective for strengthening the abdominal muscles, making them an excellent addition to any strength training routine.

Unlike traditional crunches, cable crunches use a cable machine, which provides constant resistance throughout the entire range of motion. You can adjust this resistance to match your fitness level, allowing you to progressively overload your abs, which is vital for muscle and strength gain.

Moreover, because cable crunches allow you to strengthen your entire core, they can greatly improve your core stability, which can make everyday tasks easier, decrease the odds you’ll injure your spine, and boost athletic performance.

FAQ #2: Do cable crunches make your waist thicker?

Training your abs with cable crunches builds your abdominal and oblique muscles, which might raise concerns about increasing waist size. 

However, it’s highly unlikely that cable crunches will add inches to your waistline. While this exercise develops your abs and obliques, your core muscles typically don’t grow to the extent that would significantly enlarge your waist.

The only way your waist could become appreciably thicker while following a strength training program that includes cable ab crunches is if you also regularly eat more calories than you burn, causing you to gain fat.

Also noteworthy is that ab exercises alone can’t reduce your waist size. 

To make your waistline noticeably slimmer, you must eat fewer calories than you burn daily, otherwise known as a “calorie deficit.”

If you eat in a calorie deficit and perform ab exercises, such as cable crunches, you’ll lose fat, shrink your waist, and develop more prominent abs, which together will give you the “6-pack abs” many people want. 

FAQ #3: Are cable crunches bad for your back?

In recent years, some scientists have suggested that crunch-type exercises may cause tightness in the hip flexors and lower-back muscles. This tightness “tilts” your pelvis forward into anterior pelvic tilt and, in doing so, increases your risk of lower back pain.

There are several reasons to doubt this stance, though. 

First, evidence doesn’t strongly support the idea that anterior pelvic tilt causes back pain. 

Research indicates that individuals with and without lower back pain often have similar spine curvature and pelvic tilt angles. In some cases, studies have found that people with lower back issues may have a less pronounced curve in their lower back compared to those without such problems. 

Furthermore, there’s no consistent evidence linking changes in pelvic tilt or the angle of the lower back to the development of lower back pain.

Second, studies don’t substantiate the belief that tight hip flexors contribute significantly to pelvic tilt or curvature of the lower back.

And third, only a couple of studies have made this link. Until more robust research confirms their findings, it’s sensible to approach these claims with caution.

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