One of the most common questions that I get asked as a Certified Personal Trainer is, “How many crunches a day should I do to see results?”
Right off the bat, I usually tell all of my clients that doing crunches is not the most effective way to strengthen your abdominal muscles1Escamilla, R. F., Lewis, C., Bell, D., Bramblet, G., Daffron, J., Lambert, S., Pecson, A., Imamura, R., Paulos, L., & Andrews, J. R. (2010). Core Muscle Activation During Swiss Ball and Traditional Abdominal Exercises. Journal of Orthopaedic & Sports Physical Therapy, 40(5), 265–276. https://doi.org/10.2519/jospt.2010.3073or improve functional core strength.
From there, we work on some more effective core exercises instead of regular crunches. One of the closest alternatives to crunches that I recommend in certain cases is the stability ball crunch. So, how many stability ball crunches should I do, you ask?
Stability ball crunches still aren’t recommended for all individuals, but this exercise can be a great beginner-friendly ab exercise for people who can safely do spinal flexion.
In this guide, we will discuss how to perform crunches on a stability ball, the benefits, how to modify stability ball crunches to add variety to your ab workout routine, and ultimately answer your question, how many stability ball crunches should I do in my gym workouts.
Let’s jump in!
How Do You Do Stability Ball Crunches?
Before we look at how many stability ball crunch reps you should do, let’s cover how to perform stability ball crunches.
Stability Ball Crunch
- Lie back on the stability ball so that your head and neck are off of the ball and your hips and knees are bridging off of the ball. Your knees should be bent to 90° and your feet should be flat on the floor hip-width apart.
- Cross your arms over your chest or place your hands behind your ears, gently cradling your head.
- Inhale, contracting your abs to lift your head and shoulder blades up while keeping your lower back and hips on the ball. Instead of thinking about curling up so that your face is looking at your feet, think about lifting your upper body with your abs as you keep your gaze pointed at the ceiling. (Think “up” not “forward.”).
- Pause and hold this lifted position, squeezing your abs and thinking about sucking in your stomach to press your belly button and lower back into the ball.
- Slowly lower your upper body back down, extending backward beyond neutral a bit before beginning the next rep.
You can also do crossover stability ball crunches by lifting up and towards the opposite leg (like a bicycle crunch).
Are Stability Ball Crunches Good for Abs?
Stability ball crunches are crunches that are indeed beginner-friendly and can help strengthen your abdominal muscles.
However, for certain populations, performing any type of crunches—even stability ball crunches—is contraindicated because of the flexion it imposes on the spine.
For example, if you suffer from osteoporosis or low bone density in your spine, or you have degenerative joint disease, spinal stenosis, or herniated discs, doing crunches can increase your risk of further damage such as causing vertebral compression fractures or exacerbating narrowing between your vertebrae.
Women who are pregnant or men who are dealing with diastasis recti2Hall, H., & Sanjaghsaz, H. (2022). Diastasis Recti Rehabilitation. PubMed; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK573063/should also avoid doing stability ball crunches because of the increased intra-abdominal pressure3Escamilla, R. F., Lewis, C., Pecson, A., Imamura, R., & Andrews, J. R. (2016). Muscle Activation Among Supine, Prone, and Side Position Exercises With and Without a Swiss Ball. Sports Health, 8(4), 372–379. https://doi.org/10.1177/1941738116653931and positioning inflicted by the crunch movement pattern.
Alternative core exercises that do not require final flexion are recommended in all of these cases.Examples include forearm planks, high planks, side planks, Pallof presses, bird dogs, dying bugs, and potentially more dynamic exercises such as medicine ball chops.
What Are the Benefits of Stability Ball Crunches?
Regular crunches involve strengthening the abs in the flexion directions because the range of motion is limited by the flat surface of the floor.
The benefit of using a stability ball for crunches is that you can drape your spine over the curve of the Swiss ball, allowing you to extend your spine and work through a wider range of motion.
Plus, due to the extension backward beyond the neutral position, the rectus abdominis abdominal muscles undergo a larger range of motion specifically for eccentric contraction (lengthening under tension).
Studies have found4Schoenfeld, B. J., Ogborn, D. I., Vigotsky, A. D., Franchi, M. V., & Krieger, J. W. (2017). Hypertrophic Effects of Concentric vs. Eccentric Muscle Actions. Journal of Strength and Conditioning Research, 31(9), 2599–2608. https://doi.org/10.1519/jsc.0000000000001983that hypertrophy (muscle growth) and strength gains seem to be most significant with the eccentric phase of an exercise.
Therefore, you should be able to achieve faster gains in ab strength and definition with stability ball crunches vs regular crunches on the floor.
Note that muscle definition in the abs (“six-pack abs”) will only be visually apparent at a low enough body fat percentage, but you can build muscle in your abs even if it is covered by body fat.
Another benefit of doing crunches on a stability ball instead of the floor is that the stability ball has a tendency to want to roll around and it isn’t stable and flat like the floor.
This means that balancing your trunk and stabilizing your pelvis off the ball requires greater activation5Sasaki, S., Tsuda, E., Yamamoto, Y., Maeda, S., Kimura, Y., Fujita, Y., & Ishibashi, Y. (2019). Core-Muscle Training and Neuromuscular Control of the Lower Limb and Trunk. Journal of Athletic Training, 54(9), 959–969. https://doi.org/10.4085/1062-6050-113-17of the internal and external obliques, deep transversus abdominis and other deep core muscles, the pelvic floor muscles, and deep back/core muscles like the psoas, multifidus group, and quadratus lumborum.
This makes stability ball crunches in much more functional exercise than regular crunches or sit-ups on the floor.
In order to effectively optimize the functional strength of your core muscles, you need to train the core to not only permit—but also restrict and stabilize against—lateral flexion (side bending) and rotation.
The moving nature of the stability ball forces these stabilizing core muscles to control and restrict unnecessary twisting and rotation of your trunk during yoga ball crunches so that you can just flex and extend the spine without any accessory motions.
The primary muscles worked by stability ball crunches are the abs—which include the rectus abdominis, internal and external obliques, and transversus abdominis.
This is the “six-pack muscle“ that runs up the center of your torso and is involved in the flexion of the trunk.
The core motions discussed above (lateral flexion and rotation) are primarily controlled and supported by the obliques6Oliva-Lozano, J. M., & Muyor, J. M. (2020). Core Muscle Activity during Physical Fitness Exercises: A Systematic Review. International Journal of Environmental Research and Public Health, 17(12), 4306. https://doi.org/10.3390/ijerph17124306, the abdominal muscles that run along the sides of your torso.
Therefore, these muscles worked by stability ball crunches are not prime movers in the sense that they are directly helping you crunch up and down as much as they are contracting isometrically to stabilize your core so that you can perform crunches on the unstable ball.
Stability ball crossover crunches work the rectus abdominis muscle like regular stability ball crunches, but the crossing-over movement also activates the obliques more directly.
Thus, one of the benefits of this variation of stability ball crunches is that it is an excellent functional core exercise because it trains your abs to work together across several planes of motion, which replicates real-life applications.
This ab exercise incorporates some transverse plane motion, frontal plane motion, and sagittal plane motion.
How Many Stability Ball Crunches Should I Do A Day?
As with any strength training exercise, the number of stability ball crunches you should do depends on your fitness level, training goals, and the other workouts and exercises you are performing for the muscles worked by stability ball crunches.
Here are a couple of guidelines for how many stability ball crunches you should do:
How Many Stability Ball Crunches Should I Do If I Am A Beginner?
For beginners, a good starting place is two sets of 10 to 12 reps. Build up to three sets of 10 to 20 reps.
How Many Stability Ball Crunches Should I Do to Build Strength?
If you are advanced and have strong abdominal muscles, add resistance by doing cable machine stability ball crunches, holding a weight plate, or using resistance bands.7Sundstrup, E., Jakobsen, M. D., Andersen, C. H., Jay, K., & Andersen, L. L. (2012). Swiss ball abdominal crunch with added elastic resistance is an effective alternative to training machines. International Journal of Sports Physical Therapy, 7(4), 372–380. https://pubmed.ncbi.nlm.nih.gov/22893857/
Perform 3-5 sets of 6-12 reps to build strength and muscle.
It’s better to add more resistance and perform fewer stability ball crunch reps per set to increase ab strength and build muscle.
However, make sure you can safely handle the weight and you’re not straining your abs, hip flexors, or spine.
How Many Stability Ball Crunches Should I Do to Build Muscle Endurance?
The number of stability ball crunches you should do for muscle endurance depends on numerous factors, but a good general recommendation is to perform 3-5 sets of 15 or more reps.
With any strength goal or fitness level, try to perform a variety of core exercises so that you have a well-rounded core strengthening routine.
For more great workout ideas, check out some other stability ball exercises here.
