Crunches: We’ve all heard of them, and most of us have probably thrown a set or two into a workout, but have you ever stopped to ponder how crunches benefit us?
As a classic core exercise, traditional crunches are a dynamic flexion movement designed to target rectus abdominis muscles, one of the four abdominal muscles commonly referred to as the "abs" running along the center of the midsection. Safe to perform and requiring only our body weight, crunches have long been hailed as a go-to core-strengthening movement, and, according to research, are more effective than using some popular ab-targeting equipment. A study conducted in 2014 by the American Council of Exercise found trainers reaped greater muscle activation with crunches than with exercises performed on ab equipment like the Ab Roller—even planks had significantly lower muscle activation than a traditional crunch.
As one of many on a long list of abdominal exercises, crunches have earned their role in fitness repertoires as an effective movement to isolate and tone the abs. Keep in mind, however, that they’re not as useful if fat burn is your goal. In fact, according to an online crunch calculator, it would take around 10 hours for a 150 pound person to burn 3,500 calories, equal to one pound.
That’s not to say we should disregard the crunch as an important element of a well-rounded fitness routine. Whether you want to get down to basics, or elevate your crunch, read on.
Meet the Expert
How to Perform the Perfect Crunch
As with any exercise, maintaining proper form and movement is essential for both injury prevention and to achieve the most from your session. Crunches require a straight alignment of the neck and spine—the challenge being to hold this position throughout the duration of the exercise.
“Clients will often complain of neck or back pain when crunching, so the first thing I set out to do is teach them how to do a crunch, or, what is known in Pilates as the Pilates curl, properly," says Alo Moves Pilates Instructor & Real Pilates® Instructor Tela Anderson.
Her three-step approach to the perfect crunch:
1. Lay on your back with your knees bent, and feet on the mat. The feet should remain a comfortable distance away from the buttocks.
2. Place one hand on top of the other and place them behind your head, with the elbows wide to the side. Inhale to prepare, and as you exhale, scoop the navel to the spine bringing your chin towards your chest (not onto the chest) and lift your upper back off the ground until the tips of the shoulder blades hover around 1-2 inches in the air.
3. Lower the body down until the tips of the shoulder blades touch the floor, then again lift the shoulder blades back up 1-2 inches off the floor, making sure to keep scooping the navel to the spine.
More of her useful tips include: ensure the elbows remain wide throughout the movements, avoid pulling on the neck (the abs should be enhanced enough to do the work), and keep the tailbone heavy on the mat to avoid lifting the glutes off the mat as the upper body rises.
For those who benefit from visualization, Founder of Xtend Barre Andrea Rogers envisions: “Imagine you have an orange resting on your neck, and avoid squishing it as you curl up and down. Curl your bottom ribs to your hips as you come up, lifting the head, neck and shoulders up before returning back down, using control rather than speed to maximize your results.”
For those of us new to exercise or specifically abdominal work, she advises combining crunches with other abdominal exercises 3-5 times a week, before building it up to a daily practice for more impact.
When to Avoid Crunches
Crunches may indeed rule as one the best exercises for strengthening our abdominal muscles, but be wary—they are not suitable for everyone. “Anyone with a lower back injury, as well as prenatal clients, should avoid this exercise,” states Rogers.
Given our abdominals and lower back form a part of the core, a group of muscles working together to stabilize and support the trunk of the body, the motion of crunching requires a degree of lower back strength. Any unwelcome strain on the lumbar region (lower back) can worsen a preexisting condition. “Exercises such as alternative leg curls/lifts, or placing a playground ball behind the lower back for support are safer modifications to strengthen your core.”
As for prenatal clients, compression of the tummy can restrict blood flow to the heart, leading to dizziness and potential dangers to your baby. During, and immediately after pregnancy, it’s best to avoid crunches altogether.
Common Crunch Mistakes
“In Pilates especially, performing crunches properly and without pain is key if you want to reap the benefits,” says Anderson.
Whether you’ve been crunching for years or are new to the mat, mistakes can arise for a few reasons, sometimes due to body misalignment, other times from failing to engage the required working muscles. “The biggest mistake I see is either pulling hard on the neck to hoist the chest off the floor which can hurt the neck over time, and also straining the front neck muscles by keeping the chin lifted as you lift off the mat,” explains Anderson.
All speed and little control is not the recipe for the perfect crunch, defeating the purpose of the exercise altogether. Aim for a steady pace throughout the movement, and stop to readjust if you feel any pain.
Mix Up Your Crunch Style
Getting bored of the traditional crunch? Spice it up with a crunch variation or two. Rogers suggests pairing a basic crunch to target the abs, with a side to side twist to work the obliques (the muscles running alongside the rectus abdominis), or performing a reverse crunch (lifting your tailbone off the mat). “Reverse crunches are a great way to target the lower abdominals and change up your traditional crunches.”
Or, up your crunch game with a few simple adjustments, as outlined by Anderson: “To increase the intensity of your crunches, you can add weights to the hands, or perform them on an incline or decline, or, you can also perform them with legs in the air.”
For a more intense and all-encompassing approach to your ab-focused workout, you can stir in other abdominal targeting exercises. “Adding movement to the lower body, as well as varying the abdominal choreography, brings our clients the maximum results when strengthening their core,” says Rogers. “Moves like scissor criss-crosses, tabletop leg lifts, and single leg extensions are used to strengthen the core far more than just performing daily crunches”. Aside from this, she points to the plank as still an effective alternative for those unable to perform crunches, or who want to add a dash of variety to the routine.
Crunches are a safe (for most) and effective abdominal move to throw into our workouts, performed using just body weight for a no-fuss, go-to exercise at any time. With proper form, alignment, and control, crunches reign as a staple exercise in putting our abdominal muscles to work. Although they’re not the optimum fat burning exercise in their own right, crunches will help strengthen the muscles in the core and are a perfect accompaniment to other ab and core-fueled exercises.