Ask the Professor: Are Crunches Bad for You?

Professor Erin Calderone answers this burning question about crunches.

Are crunches bad for me?

People love to categorize things as being good or bad, but when it comes to crunches, there is no absolute. The answer is far more nuanced and requires an assessment of your individual needs and goals.

Woman doing a crunch

Are crunches bad? The answer depends on your needs and goals.

Risk vs. Reward

There is no shortage of studies highlighting the potential risks of crunches, the most obvious being lower-back pain or injury, since thousands of cycles of spinal flexion (bending forward) with varying levels of compression may cause damage to your spinal disks. And indeed, researchers have crushed dozens of pig spines trying to determine this hypothetical upper limit, but the idea that your spine has a finite number of bends isn’t exactly accurate, and crushing pig spines in a laboratory isn’t quite the same as doing a few sets of crunches over the course of a week. Additionally, ample rest allows tissues to heal and become stronger, theoretically increasing the total number of bends your spine can withstand over time.

It is true, however, that habitual compression could cause your disks to bulge, pressing on nerves and causing lower-back pain and/or sciatica. And since many of us spend eight or more hours per day in a spinal-flexed position — e.g., hunched at a desk, in a car or on the couch — it makes sense that replicating that position in the gym is probably not the best idea. That being said, back pain is not relegated to habitual sitters, and research indicates that excessive training and complete lack thereof are equal predictors of back breakdown, meaning that avid exercisers rank right alongside career couch potatoes when it comes to back issues.

The trick, then, is to apply just enough stress to your body by training the entire core with a variety of movements in a progressive fashion to get results and prevent injury.

Is It Crunch Time?

When done properly, spinal flexion exercises are powerful stimulators for the rectus abdominis, so if your goal is hypertrophy and a defined six-pack, then things like crunches, pikes and twists can be included in your programming. Other candidates for dedicated flexion training are athletes who require strength and endurance in this position such as gymnasts, martial artists, CrossFitters and even ball/racket athletes. And because the fitness “law” of specificity dictates that you get better at what you train for, these athletes should include moves such as crunches as part of their all-around core conditioning.

So should you personally include crunches in your programming? Maybe. Here are some suggestions for core and abdominal training depending on your fitness and experience level.

Beginner Rx: Stabilize

Novice exercisers — and those with sensitive backs — should focus on stability training until you have built a solid base. Practice isometric exercises like planks, Bird Dogs and dead bugs regularly to build endurance in the muscles that support your spine.

Intermediate Rx: Resist and Strengthen

Intermediate exercisers with a solid base can add some dynamic movement to an isometric exercise — for example, a plank with a band row, a Pallof press or a single-arm farmer’s carry. If they support your sport or training goals, you can add some crunches and twists to your schedule, but make sure you include a variety to hit all areas of your core — for example, a standard crunch, a reverse crunch, a rotational woodchopper and a back extension.

Advanced Rx: Strength and Power

Advanced athletes who need heightened core strength should still practice all the base-level stability moves for maintenance and optimal strength but can amp the exercise difficulty to match your ability — for instance, adding a band to a Bird Dog, doing a plank walkout or adding weight to a standard crunch. Include a variety of sport-specific moves to develop power in your trunk such as medicine-ball throws and toes-to-bar cycling, and you can add power and speed to a strength move in the form of fast V-ups or high-volume clusters of band rotations. 

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