Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In

Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In



Why You Should Stop Doing Crunches

It might come as a shock that a good core strengthening program should not include crunches.

Adapted with permission of VeloPress from Core Envy: A 3-Step Guide to a Strong, Sexy Core by exercise physiologist and personal trainer Allison Westfahl. Learn more at

Stop Doing Crunches!

It might come as a shock that a good core strengthening program should not include crunches! 

As an exercise physiologist, I omit crunches from my personal training programs because they don’t utilize a significant percentage of your core musculature.

While it feels like you’re working hard when you’re 70 reps into a grueling round of 100 crunches, you are predominantly working a single muscle group—the rectus abdominis (rectus). In actuality, the true “core” of the body includes countless other muscles. It’s all the core muscles that affect how well you move—and how good you look.

This brings up the issue of function versus vanity. Why wouldn’t you want to focus your gym time on developing a rockin’ rectus? Aren’t those the beach muscles that look great with a spray tan? If a well-developed rectus is what turns heads, do we really need a well-rounded core routine that works all the other muscles?

The short answer is that a high-functioning core leads to a better-looking core. 

Focusing on only a few core muscles can lead to poor posture (which makes your tummy stick out) and injuries (which will inhibit you from being able to work out). Build a solid foundation for your core with a well-rounded core routine, and you will accomplish the dual goals of looking good while being strong and pain-free.

What is a “core workout” anyway?

A good core workout works a lot more than just your ab muscles. 

When I talk about the foundation for your core, I’m not referring just to the intricate musculature beneath your abs. Your glutes and hamstrings are also involved. These muscles are traditionally categorized as “lower-body” muscles, but they serve a dual function in helping to stabilize and move the pelvis, which makes them part of the core. In fact, any muscle that is attached to either the pelvis or the spine is technically part of the core. Add to the major muscle groups all of the smaller, deeper muscles in this area, and the count of how many muscles are in the human core easily reaches into the hundreds. If your core strengthening routine is based solely on crunches, you’re neglecting 95 percent of your core musculature.

When a large percentage of your core muscles is routinely ignored, it creates a muscular imbalance in which a muscle or group of muscles becomes tight and overactive, therefore causing a neighboring or opposing muscle to become weak and underactive.

Overworking one core muscle group will weaken the others.

Core imbalances are problematic because our muscles control our joints and bones, and when a certain muscle is doing too much work, it will start to pull the bones and joints it is attached to into uncomfortable positions.

Feeling The Burn Doesn’t Mean You’re Burning Calories!

The term “burn” has been associated with exercise for a long time: Feel the burn, burn away fat, calorie burn, burning muscles . . . the list goes on and on. We all want to feel that the exercises we are doing are effective and worthwhile, and that burning sensation we get while doing a specific movement helps us feel that we are working hard, burning lots of calories, and therefore tightening the muscles that are burning. But what exactly is that burning sensation, and is it really a barometer for the effectiveness of a workout?

Contrary to popular belief, the burn that we feel in our muscles during exercise is not directly related to caloric burn or the amount of fat that is being burned. Just because you feel a burn in your abdominal muscles during a crunch, it does not mean that your body is burning fat in that area.

That sensation in your muscles is actually something else: an indication that those muscles are out of ATP, a cellular fuel your muscles burn for quick energy. That’s all it means. It doesn’t mean you’re burning a ton of calories; just that your muscles have burned all their stored ATP.

What you need to know for the purposes of fat loss is that the higher you get your heart rate, the more calories you will burn. It’s tempting to base the effectiveness of a workout on how much “burn” you feel in the muscles, but it’s the intensity and duration of the workout that will truly determine how many calories—and therefore how much fat—you are melting away.

You can’t lose much fat doing crunches!

Most traditional core exercises are not scorching a lot of calories. 

You can do crunches all day long and see no change to the fat you store around your midsection because your heart rate isn’t high enough, which means you aren’t burning calories at a significant rate. Again, it might feel as if you’re working hard because your ab muscles are burning and you can’t do more than 20 reps, but if you were to wear a heart rate monitor during crunches, it would show that your heart rate rarely gets above 90 beats per minute. When it comes to burning fat and losing weight, your heart rate is the prime indicator of success. It’s simple math: The higher your heart rate, the more calories you burn, and the more calories you burn, the more fat you lose. One pound of fat is equal to 3,500 calories, so you need to focus on exercises that will get your heart rate high enough to burn the maximum amount of calories in the shortest amount of time.

The higher your heart rate, the more calories you burn, and the more calories you burn, the more fat you lose.

How will you know which types of workouts are maximizing your fat loss? In 2005, the Journal of Sports Sciences published a study that outlined an equation to predict the number of calories burned per hour based on your average heart rate. We can apply this equation to different types of sculpting and cardio routines to determine which ones deliver the best results. As the oft-used adage goes: Don’t work harder, work smarter.

Let’s take the old crunches-based core routine as a starting point for caloric burn. If we assume an average heart rate of 90 beats per minute (which is the heart rate most of my clients exhibit while doing crunches), a 40-year-old female who weighs 160 pounds will burn approximately 195 calories in an hour. You could burn that many calories in 20 minutes by doing a moderate jog. Plus, when was the last time you did crunches for an hour? Most of us can last about 1 minute, which translates into 3.25 calories burned— that’s less than the calorie content of a breath mint. This is one of the myriad reasons why you won’t see standard crunches in my Core Envy sculpting routines. Instead, I’ve focused on exercises that recruit more of the muscles in the core, therefore burning off calories faster by elevating your heart rate. Keep in mind, however, that in order to truly maximize the fat burn around your belly, these sculpting workouts need to be paired with cardio. Sculpting routines alone cannot ensure optimal caloric burn.

You have to lose it all.

We all store fat in different areas of our bodies; women with pear-shaped bodies tend to store more in the hips and thighs, while women with apple-shaped bodies store more in the abdomen and upper arms. When you want to reduce fat in a specific area of your body, it would seem reasonable to do exercises that work the muscles in that region. So if you want less fat on your thighs, you do lunges; if you want less fat on your arms, you do biceps curls; and if you want to burn off that spare tire, you do core exercises. Seems perfectly logical, doesn’t it? Unfortunately, this approach to fat reduction is simply false. The reason we can’t microtarget fat areas is that fat is stored primarily in the form of triglycerides. These triglycerides might tend to collect more in certain areas (such as the abdomen or thighs), but that doesn’t mean the muscles of that area are using those specific triglycerides for fuel.

When we need energy to move, our body will call upon the stored energy in our fat cells and convert that energy into fuel that our muscles can use. Just because we have fat cells in our stomach doesn’t mean our body will choose those particular fat cells to convert to energy when we’re doing core exercises. In short, the fat cells in our stomach don’t “belong” to the muscles of the stomach. The body will pull energy from fat cells in many different areas of the body and will use that fuel to help power whatever activity we are doing. For this reason, the key to burning fat as quickly as possible is to choose activities that burn the highest number of calories, in turn eliminating the highest amount of fat. In the next chapter, we will look at which types of workouts are the most effective for burning fat calories, and we’ll examine why manipulating your heart rate is the key to losing belly fat.

Work your whole core!

Most core exercises, especially any exercise that includes “crunch”, are not, in fact, going to create the sleek, toned belly you want. So why should we do core exercises at all?

Since doing high-intensity cardio burns fat more effectively than crunches, why shouldn’t we just do cardio all day long and ditch the brutal core routines?

Here’s why:

Working the core in a functional, progressive manner will give you nice, lean muscles that will be on display once that layer of fat is burned off by doing cardio and cleaning up your diet.

You don’t want to spend months burning off that spare tire to reveal, well, nothing underneath.

While core exercises are not the most effective way to burn subcutaneous and visceral fat off your belly, they are the answer to toning the muscles underneath. As stated earlier, spot-reducing fat from your body is not realistic, but spot-toning your muscles most certainly is. For example, you can absolutely make the muscles in your legs stronger and more toned by doing lunges and squats; this maxim holds true for any muscle in the body. Putting repetitive stress on a muscle causes positive adaptations in those muscle fibers that range from improved cardiovascular efficiency to increased bone density and neuromuscular control. The bottom line is that if you put repetitive stress on your core muscles by doing the sculpting exercises in this book, you will improve the strength, power, endurance, and coordination of those muscles.

All of these benefits are just lovely side effects of sculpting a gorgeous, enviable core!

[velopress cta=”See more!” align=”center” title=”Buy the Book”]