Lets face it the traditional abdominal exercise – the crunch – is a staple exercise for many from the weekend warriors to the college athletes. The crunch has been around for decades and when I typed in “crunch exercise” into Google I pulled up almost three million results with the top ones being videos of how to perform a crunch. So, naturally you would think the crunch is an effective way to exercise your abdominals. Wrong!
It has been known for years that crunches are not a very effective abdominal, or core, exercise. Furthermore, there is no need to crunch your workout away with minimal results when there are plenty of more effective and creative core exercises. So, why do you still see fellow exercisers at the gym crunching away, enticing you to do the same? One, you can feel it in your abs when you crunch properly; and two, the crunch and its predecessor the sit-up have been taught as fundamental exercises from generation to generation.
To understand why crunches are a waste of time for most, if not all, exercisers, we must address two questions first. What are your abdominal and core muscles? And what is the function of your core muscles? If you don’t want to be left in the dark about your core workout any longer, knowing and understanding the answer to these two questions is of utmost importance.
What are your core muscles?
You may hear and read “core muscles” and “abdominal muscles” used synonymously. However, it is not entirely correct to do so. Abdominal muscles are core muscles, but core muscles are not necessarily abdominal muscles. Abdominal muscles include your transverse abdominis, rectus abdominis, internal oblique, external oblique and pelvic floor muscles. Your core muscles encompass these abdominal muscles plus, the multifidus, erector spinae, latissimus dorsi, and quadratus lumborum of your back; and the gluteus maximus, abductors, and adductors of your hips. [Note: Depending on your source, what are labeled as core muscles may vary slightly.]
What are the functions of your core muscles?
Your core muscles stabilize and move your pelvis and torso. They help you maintain upright posture and balance during tasks such as reaching for your favorite jar of natural peanut butter on the top shelf. Movements these muscles are responsible for include, forward and side flexion, torso extension and rotation of your hips and torso.
How do core exercises affect core muscles?
Core exercises can be categorized as the following:
* Isometric - is when your core muscles are contracting but not lengthening or shortening – meaning, you use them to hold a position. Planks are a great example of an isometric core exercise. These isometric, or stability, exercises should be mastered first.
* Concentric and eccentric – is when one or more of your core muscles contract, or shorten, and then lengthen again. Crunches are an example of a concentric and eccentric exercise.
* Rotational – is when you rotate your toros or hips. If you only rotate your torso, you are often stabilizing your pelvis. Standing Russian twist is an example of a rotational core exercise.
Besides the mechanism of the core exercise, varying the resistance, pace, repetitions, sets and frequency also contribute to the effectiveness of the core exercise routine.
What is wrong with the crunch?
So this leads us back to, “what is wrong with the crunch?” First the crunch is not a very functional exercise. It is performed lying on your back and is a one-plane movement, which makes crunches less dynamic and, therefore, less functional in nature than many alternatives, such as kneeling superman.
Furthermore, crunches primarily target the rectus femoris muscle. Constant flexion of the spine and muscle imbalances between the rectus femoris and transverse abdominis may contribute to low-back pain or re-aggravate a previous low-back injury.
Research also shows that crunches must be performed no higher than approximately 30 degrees flexion. Otherwise your hip-flexor muscles kick in and diminish the effectiveness of the exercise and might cause further pain or back problems.
What are some effective core exercises?
Below are core exercises I would recommend including into your exercise routine in replacement of crunches. You can start with adding them one at a time. When you are ready you can combine three or four of them together to make a core circuit. Duration, repetition and sets will vary depending on your fitness level. Just remember to start slow and increase gradually.
* Planks: isometric. Watch video here . [Note: variations may include concentric/eccentric movements]
* Posterior pelvic tilts into bridges: concentric/eccentric and isometric. Watch video here .
* Single-leg balance: isometric. Watch video here .
* Russian twist: rotational
* Lunges and squats with torso rotation: rotational and isometric. Watch video here .
* Deep breathes: concentric/eccentric [Note: expand chest and ribcage as you inhale then force air out as you exhale, bearing down slightly, and repeat.]
If you just cannot give up your traditional crunches, here are some suggestions on making them less problematic and more effective.
* Perform crunches lying on an exercise ball to support your back.
* Crunch only to 30 degrees flexion. This means only curling high enough to lift your shoulder blades off the ball.
* Curl your neck, or tuck your chin, before you go into the crunch.
* Exhale into the crunch and inhale as you relax out of the crunch.
Your core is a diverse set of muscles that require a variety of dynamic exercises to keep them functioning optimally. So kick the crunches to the curb and up-grade your core workouts. You will not be disappointed in the results!
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Stop performing crunches or perform on an exercise ball
Add additional dynamic and functional core exercises to your routine
Akuthota, V., et al. (2008). Core Stability Exercise Principles. Current Sports Medicine Reports, 7 (1), 39-44.