Cable crunches are often done wrong. Instead of actually crunching, people bow to a statue. This will not deliver the results they want.

“The abs do not get worked this way,” I’d tell people at the gym where I worked as a personal trainer some years ago.

Cable crunches trim the abdominal area by causing the muscles to tighten and “compress.” The result is that the area “caves in” a little; creating definition and literally, a smaller waistline.

When people do cable crunches, their objective is to hit the abs hard. What many don’t realize is that instead of targeting the abdominals, they are hitting mostly the lower back by doing the cable crunches incorrectly.

You want to target the abs, not the lower back. Here are the classic mistakes that people make with the cable crunch:

Instead of crunching (curling trunk inward), people instead lower down by using their lower back, with very little crunching motion at the abs.

  •  They sit on their heels as they lower; butt atop heels. This takes load off the abs, when you should be loading the abs.
  •  Their arms yank at the rope or whatever pulling device they’re using. I use only the rope; it’s the best device for cable crunches. If you pull on the rope, you take work away from the abs.
  •  The last mistake with cable crunches is using so much weight that the person is not able to do curl in a full range of motion with the abs.

Think of the cable crunch as an inverted crunch. When you do a typical crunch, your trunk folds up and your head comes towards thighs. So when you do cable crunches, this same motion should be happening: back flexion.

Merely bobbing up and down from a lower-back pivotal point will not target the abs.

Only your lower back gets the workout. This is a common mistake with cable crunches: The person keeps back straight while bouncing up and down from the lower back.

When you perform cable crunches while sitting on your heels, this sabotages best effort at curling in the trunk and abs.

Again, think of a regular crunch. Regular ones are often performed with legs positioned up in the air, thighs vertical, and calves horizontal: a 90-degree bend. So when you do cable crunches, duplicate this position.

Thighs should form a 90-degree angle with calves. Do not sit back on legs.

To avoid getting arms involved, they must be firmly against sides of head. This way, they integrate with your head, and become part of the weight you are pulling.

Many people make the mistake of pulling the weight down with their hands, yanking with forearms and shoulders, fooling themselves into thinking their abs are doing this work.

Using too much weight will prevent you from using correct form. If the weight is heavy enough, you will not be able to curl your trunk/abs in as tightly as possible. For best results with the cable crunch, your rep range should be 20-35.

How to do a cable crunch: step-by-step.

Set weight a lot lighter than usual. For men, I recommend 100-120 pounds. For women, 80-100.

Do not assume this is too light, because when you bring proper form and 20-35 reps into the picture, this much-lighter weight will be challenging.

Use the rope for the hand device, and hold it just above the knobs or knots.

Grab rope while standing, then get to knees.

Determine where knees should be on the floor (use a mat), so that if you were to bend forward at the pelvis, your head will have room to come down without grazing the weight stack.

Set yourself up in the start-position: upper legs vertical, forming 90-degree angle with lower legs.

Maintain this angle throughout the entire cable crunch set.

While holding rope, place inside of forearms tightly against ears. Forearms should be parallel to each other.

Your back is parallel to floor in this start-position, though it should have a slight arch.

Now, without losing that 90-degree angle with your legs, curl trunk as though you want to touch elbows to thighs.

If elbows hit the floor, you are not cable crunching correctly.

However, elbows will probably not make it to your thighs. This is normal.

As long as elbows are on track to meet thighs, you know you are cable crunching properly.

As you progress into the curl, round out the back. If you keep it arched, you’ll have difficulty with form.

For cable crunches, you will be arching low back (when you uncurl), and then rounding (when you curl).

However, back pretty much stays parallel to the floor, within the range of the arching and curling.

At some point, you will not be able to go further because your abs will begin fatiguing. At this point, force a few more inches into the crunch. Then hold it there for two seconds.

Release the crunch and return to the start position, with back slightly arched. Repeat the motion for another cable crunch.

If you do this correctly, without any cheating or veering from form, your abs will start burning between 20 and 35 reps. Rest one minute, then repeat for two more sets, 2-3 times per week.

Cable crunches are the best way to get abdominal definition and take an inch off the abdominal area, in the way I explained previously.

Cable crunches will NOT burn fat. They “compress” or reduce the abdominal circumference by working the muscle. Fat loss has nothing to do with this process.

So if you have excess fat in your abs, the effects of cable crunching won’t show as much.

I’ve had overweight clients who actually developed abdominal definition from cable crunches, but the fat was still there.

However, a fatty midsection with definition looks far better than a fatty midsection with NO definition.

Lorra Garrick is a former personal trainer certified through the American Council on Exercise. At Bally Total Fitness she trained women and men of all ages for fat loss, muscle building, fitness and improved health.