Core Stiffness: What It Is and Why It’s Important

Core Stiffness: What It Is and Why It’s Important

Core Stiffness – You hear a lot about core training these days. No wonder! Firing up your core muscles helps you get a stronger midsection and greater protection against injury. Having strong core muscles gives you better control over the way your body moves.

Your core is smack dab in the middle of your body where it’s perfectly positioned to impact the movements your upper and lower body make. If you play sports, core training will improve your performance, and even if you don’t, a strong core will help you carry out the functional movements you do on a daily basis more efficiently and with less likelihood of injury.

The Muscles that Make Up Your Core

Your core is made up of a surprisingly large number of muscles. The major muscles include the transversus abdominis, internal and external obliques, multifidus, rectus abdominis, obliques, erector spinae, the pelvic floor muscles, and the diaphragm. The minor muscles are the gluteus maximus, latissimus dorsi, and trapezius. These muscles work together to stabilize the spine, thorax, and pelvis, whether you’re standing, sitting, or moving around.

Not to mention, a healthy posture is dependent on strong core muscles. Strong core muscles are even important for breathing and preventing bowel and bladder movements when they aren’t convenient. Don’t forget, the core includes the muscles in the pelvic floor, the ones you need to be strong to prevent stress urinary incontinence, a common problem in women after menopause.

Core Strength and Core Stiffness

What you hear less about is the concept of “core stiffness” and how to build it, since that’s what you need for maximal functional performance and protection against injury. A measure of core stiffness is how easily your trunk can resist movement. A stiff core is also the protector of the delicate tissues in your spine – and we all know how vital a healthy spine is. So, what’s the best way to get a healthy degree of core stiffness?

We know that exercises like squats and deadlifts activate the core muscles to some degree. Then there are focused abdominal exercises, like sit-ups, crunches, twists, and oblique crunches. These exercises engage the core – but are they the most effective? Not according to a study published in the Strength Conditioning Journal. These exercises are dynamic, total body exercises that also happen to work the core. The researchers in this study found that isometric core exercises are MORE effective for building core stiffness than traditional, dynamic exercises. In the study, they compared dynamic movements, including ab twists and sit-ups, with isometric exercises that target the core – and the isometric moves were more beneficial for enhancing core stiffness.

What are these isometric exercises? Planks are a good example. Planks are an isometric move that effectively targets all of the muscles in your core. The isometric moves were more effective short-term as well as 6 weeks out in developing a strong, stiff core. Based on this study, some of the best isometric exercises for developing core firmness are planks, side planks, and moves like bird dogs where you engage your core muscles for a sustained period of time. The reason dynamic ab and core exercises aren’t as effective as they don’t activate your core muscles long enough to build maximal stiffness.

How Strong and Stiff is Your Core?

How’s your own core strength and stiffness? It’s impossible to have a core that’s too strong. The core muscles act like a girdle encasing your mid-section and protecting against injury. Keep in mind, lower back pain is the most common orthopedic problem that physicians treat. While general strength training that focuses on compound exercises helps to strengthen the muscles that support the spine, studies show that core training using isometric core moves is more effective for treating back pain.

And YOUR core strength? A rough indicator is how long you can hold a plank without dropping to your knees or letting your hips sag. The average, fit individual can hold a plank for 60 seconds or longer. If you can hold one for more than 90 seconds, you’re doing well!

A sign that your core muscles are not up to par is experiencing repeated episodes of back pain. Most lower back pain arises from muscle imbalances in the core region. Sitting too much tightens the hip flexors and lengthens the glutes. Assume the sitting position too much and you’ll end up with weak glute muscles and overly tight hip flexors – a recipe for back pain and stiffness.

Sometimes, we make the problem worse by overemphasizing abdominal exercises that primarily work the hip flexors, like sit-ups and crunches. When you focus too much on abdominal strengthening over balanced core training, the strong abdominals pull your body forward and out of alignment. In turn, this places a heavier load on your spine. If you have back pain, place more emphasis on isometric core exercises that don’t involve flexion.

How to Develop Core Stiffness

Compound exercises, like the push-up, deadlift, and squat, are good for your core, don’t skip them. But also throw in some isometric exercises to get that “core of steel.” As mentioned, standard planks, side planks, and bird dogs are among the most effective exercises for strengthening and hardening your core. Glute bridges are another isometric exercise that works core musculature as well as strengthens the glutes, muscles that often weaken due to too much sitting. For more of a challenge, hold a glute bridge and lift one leg off the floor. Then switch to the other side. With so many plank variations, you’ll never get bored!

The Bottom Line

Too often we’re so focused on building muscle definition and burning fat that we forget how important core strength is for developing power when we do a variety of moves and the role it plays in injury prevention. Don’t forget that your core contributes to your posture as well. Bad posture is another sign of weak core muscles. So, now you know why core strengthening is vital and why some of the core training should be isometric. A strong, stiff core will improve every aspect of your training and your life.



American Council on Exercise. “Muscles of the Core”
J Strength Cond Res. 2015 Jun;29(6):1515-26. doi: 10.1519/JSC.0000000000000740.
Strength Conditioning Journal. 38(4): 50-65. 2016.
J Phys Ther Sci. 2015 Mar; 27(3): 619–622.
Mayo Clinic. “Core Exercises: Why You Should Strengthen Your Core Muscles”


Related Articles By Cathe:

The 3 Most Common Posture Problems and How They Jeopardize Your Health

Signs You Have Weak Core Muscles and How to Power Up Your Core

How Strong is Your Core?

Strengthening Your Core: Are Isolation or Integrative Exercises More Effective

Hate Planks? Here’s Why You Should Do Them Anyway


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